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MDGA (MAM domain containing glycosylphosphatidylinositol anchor) family proteins were previously identified as synaptic suppressive factors. However, various genetic manipulations have yielded often irreconcilable results, precluding precise evaluation of MDGA functions. Here, we found that, in cultured hippocampal neurons, conditional deletion of MDGA1 and MDGA2 causes specific alterations in synapse numbers, basal synaptic transmission, and synaptic strength at GABAergic and glutamatergic synapses, respectively. Moreover, MDGA2 deletion enhanced both N-methyl-D-aspartate (NMDA) receptor- and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated postsynaptic responses. Strikingly, ablation of both MDGA1 and MDGA2 abolished the effect of deleting individual MDGAs that is abrogated by chronic blockade of synaptic activity. Molecular replacement experiments further showed that MDGA1 requires the meprin/A5 protein/PTPmu (MAM) domain, whereas MDGA2 acts via neuroligin-dependent and/or MAM domain-dependent pathways to regulate distinct postsynaptic properties. Together, our data demonstrate that MDGA paralogs act as unique negative regulators of activity-dependent postsynaptic organization at distinct synapse types, and cooperatively contribute to adjustment of excitation-inhibition balance.
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Hipocampo , Sinapsis , Transmisión Sináptica , Animales , Sinapsis/metabolismo , Ratones , Hipocampo/metabolismo , Hipocampo/citología , Transmisión Sináptica/fisiología , Neuronas/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Ratones Noqueados , Receptores AMPA/metabolismo , Receptores AMPA/genética , Moléculas de Adhesión Celular Neuronal/metabolismo , Moléculas de Adhesión Celular Neuronal/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Células CultivadasRESUMEN
AIM: To evaluate the efficacy and safety of dapagliflozin versus placebo as an add-on in patients with type 2 diabetes who did not achieve adequate glycaemic control with evogliptin and metformin combination. PATIENTS AND METHODS: In this multicentre, randomized, double-blind, placebo-controlled Phase 3 trial, patients with glycated haemoglobin (HbA1c) levels ≥7.0% (≥53 mmol/mol) and ≤10.5% (≤91 mmol/mol) who had received stable-dose metformin (≥1000 mg) and evogliptin (5 mg) for at least 8 weeks were randomized to receive dapagliflozin 10 mg or placebo once daily for 24 weeks. Participants continued treatment with metformin and evogliptin. The primary endpoint was change in HbA1c level after 24 weeks of treatment from baseline level. RESULTS: In total, 198 patients were randomized, and 195 patients were included in the efficacy analyses (dapagliflozin: 96, placebo: 99). At Week 24, dapagliflozin significantly reduced HbA1c levels. The least squares mean difference in HbA1c level change from baseline after 24 weeks of treatment was -0.70% (-7.7 mmol/mol) (p < 0.0001). The proportion of participants achieving HbA1c <7.0% (≥53 mmol/mol) was higher in the dapagliflozin group than in the placebo group. Compared to placebo, dapagliflozin significantly reduced fasting plasma glucose, mean daily glucose, 2-h postprandial plasma glucose, fasting insulin, uric acid and gamma-glutamyl transferase levels, homeostatic model assessment for insulin resistance index, body weight, hepatic steatosis index, and albuminuria. Adiponectin level significantly increased from baseline level after 24 weeks of dapagliflozin treatment. Adverse event rates were similar in the two groups. CONCLUSION: Dapagliflozin add-on to evogliptin plus metformin improved glycaemic control and was well tolerated by the target patients.
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AIM: To evaluate the long-term safety and efficacy of enavogliflozin 0.3 mg/day added to metformin in patients with type 2 diabetes mellitus. MATERIALS AND METHODS: After 24 weeks of a randomized, double-blind treatment period with enavogliflozin 0.3 mg/day (n = 101) or dapagliflozin 10 mg/day (n = 99) added to metformin, all patients received enavogliflozin 0.3 mg/day plus metformin for an additional 28 weeks during the open-label extension period. RESULTS: Eighty-two patients continued enavogliflozin (maintenance group), and 77 were switched from dapagliflozin to enavogliflozin (switch group). All adverse drug reactions (ADR) were mild in severity. In the maintenance group, ADRs (cystitis and vaginal infection) were reported in two patients (2.44%) during 52 weeks. In the switch group, ADR (hypoglycaemia) was reported in one patient (1.30%) during a 28-week open-label extension period. At week 52, glycated haemoglobin and fasting plasma glucose were significantly lower than at the baseline, by 0.85% and 29.08 mg/dl, respectively, in the maintenance group (p < .0001 for both), and by 0.81% and 32.77 mg/dl, respectively, in the switch group (p < .0001 for both). At week 52, 68.92% of patients from the maintenance group and 64.29% from the switch group achieved glycated haemoglobin <7%. A significant increase in the urine glucose-creatinine ratio was observed at week 52, by 58.81 g/g and 63.77 g/g in the maintenance and switch groups, respectively (p < .0001). CONCLUSIONS: Enavogliflozin added to metformin was tolerated well for up to 52 weeks and provided continual glycaemic control in type 2 diabetes mellitus, along with a significant increase in the urine glucose-creatinine ratio.
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Compuestos de Bencidrilo , Diabetes Mellitus Tipo 2 , Glucósidos , Hipoglucemiantes , Metformina , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Compuestos de Bencidrilo/efectos adversos , Compuestos de Bencidrilo/uso terapéutico , Benzofuranos , Glucemia , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/complicaciones , Método Doble Ciego , Quimioterapia Combinada , Glucósidos/efectos adversos , Glucósidos/uso terapéutico , Glucósidos/administración & dosificación , Hemoglobina Glucada/análisis , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/uso terapéutico , Hipoglucemiantes/administración & dosificación , Metformina/efectos adversos , Metformina/uso terapéutico , Metformina/administración & dosificación , Inhibidores del Cotransportador de Sodio-Glucosa 2/efectos adversos , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Inhibidores del Cotransportador de Sodio-Glucosa 2/administración & dosificación , Resultado del TratamientoRESUMEN
AIM: To evaluate the efficacy and safety of gemigliptin and dapagliflozin dual add-on therapy (GEMI + DAPA) to metformin in type 2 diabetes (T2D) patients who had inadequate glycaemic control on metformin alone, compared with a single add-on of either gemigliptin (GEMI) or dapagliflozin (DAPA) to metformin. MATERIALS AND METHODS: In this randomized, double-blind, double-dummy, active-controlled, parallel-group, phase 3 study, 469 T2D patients treated with a stable dose of metformin for 8 weeks or longer were randomized to receive GEMI + DAPA (n = 157) and either GEMI (n = 156) or DAPA (n = 156). The primary endpoint was change in HbA1c levels from baseline at week 24. RESULTS: Baseline characteristics including body mass index and T2D duration were similar among groups. At week 24, the least square mean changes in HbA1c from baseline were -1.34% with GEMI + DAPA, -0.90% with GEMI (difference between GEMI + DAPA vs. GEMI -0.44% [95% confidence interval {CI}: -0.58% to -0.31%], P < .01) and -0.78% with DAPA (difference between GEMI + DAPA vs. DAPA -0.56% [95% CI: -0.69% to -0.42%], P < .01). Both upper CIs were less than 0, demonstrating the superiority of GEMI + DAPA for lowering HbA1c. The rates of responders achieving HbA1c less than 7% and less than 6.5% were greater with GEMI + DAPA (84.9%, 56.6%) than with GEMI (55.3%, 32.2%) and DAPA (49.3%, 15.3%). The incidence rate of adverse events was similar across groups, with low incidence rates of hypoglycaemia, urinary tract infection and genital infection. CONCLUSIONS: These results suggest that the addition of GEMI + DAPA to metformin as triple combination therapy was effective, safe and well-tolerated, especially for T2D patients who experienced poor glycaemic control on metformin alone.
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Compuestos de Bencidrilo , Diabetes Mellitus Tipo 2 , Quimioterapia Combinada , Glucósidos , Hemoglobina Glucada , Hipoglucemiantes , Metformina , Piperidonas , Pirimidinas , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/sangre , Glucósidos/uso terapéutico , Glucósidos/administración & dosificación , Glucósidos/efectos adversos , Metformina/uso terapéutico , Metformina/administración & dosificación , Compuestos de Bencidrilo/uso terapéutico , Femenino , Masculino , Persona de Mediana Edad , Método Doble Ciego , Hemoglobina Glucada/análisis , Hemoglobina Glucada/efectos de los fármacos , Hipoglucemiantes/uso terapéutico , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/efectos adversos , Anciano , Piperidonas/uso terapéutico , Piperidonas/administración & dosificación , Piperidonas/efectos adversos , Pirimidinas/uso terapéutico , Pirimidinas/administración & dosificación , Pirimidinas/efectos adversos , Glucemia/efectos de los fármacos , Glucemia/análisis , Glucemia/metabolismo , Control Glucémico/métodos , Adulto , Resultado del Tratamiento , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemia/prevención & control , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéuticoRESUMEN
AIMS: To evaluate the long-term safety and efficacy of enavogliflozin monotherapy (0.3 mg/day) in individuals with type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: Following a 24-week randomized, double-blind treatment period with enavogliflozin 0.3 mg/day (n = 77) or placebo (n = 69), consenting participants received enavogliflozin 0.3 mg/day for an additional 28 weeks during an open-label extension (OLE) period. The safety and efficacy of enavogliflozin were assessed at Week 52. RESULTS: A total of 37 participants continued enavogliflozin (maintenance group), and 26 participants switched from placebo to enavogliflozin (switch group). No additional adverse drug reactions related to enavogliflozin were observed during the OLE period. At Week 52, glycated haemoglobin (HbA1c) and fasting plasma glucose were significantly lower than at the baseline, by 0.9% and 24.9 mg/dL, respectively, in the maintenance group (p < 0.0001 for both), and by 0.7% and 18.0 mg/dL, respectively, in the switch group (p < 0.0001 and p = 0.002). The proportions of participants reaching HbA1c 7.0% (53 mmol/mol) at Week 52 were 69.4% in the maintenance group and 65.4% in the switch group. A significant increase in urine glucose-to-creatinine ratio was observed at Week 52, by 84.9 g/g and 67.1 g/g in the maintenance and switch groups, respectively (p < 0.0001 for both). Body weight in both groups decreased significantly (p < 0.0001) from baseline to Week 52, by 3.5 kg and 3.8 kg in the maintenance and switch groups, respectively. CONCLUSIONS: Enavogliflozin 0.3 mg monotherapy provides long-term glycaemic control in T2DM and is safe and well tolerated during a 52-week treatment period.
RESUMEN
AIMS: To evaluate the efficacy and safety of a novel sodium-glucose cotransporter 2 inhibitor, enavogliflozin 0.3 mg monotherapy, in Korean people with type 2 diabetes mellitus (T2DM) inadequately controlled with diet and exercise. MATERIALS AND METHODS: This study was a randomized, double-blind, placebo-controlled trial conducted in 23 hospitals. Individuals with haemoglobin A1c (HbA1c) of 7.0%-10.0% after at least 8 weeks of diet and exercise modification were randomized to receive enavogliflozin 0.3 mg (n = 83) or placebo (n = 84) for 24 weeks. The primary outcome was a change in HbA1c at week 24 from baseline. Secondary outcomes included the proportion of participants achieving HbA1c <7.0%, change in fasting glucose, body weight and lipid levels. Adverse events were investigated throughout the study. RESULTS: At week 24, the placebo-adjusted mean change in HbA1c from baseline in the enavogliflozin group was -0.99% (95% confidence interval -1.24%, -0.74%). The proportions of patients achieving HbA1c <7.0% (71% vs. 24%) at week 24 was significantly higher in the enavogliflozin group (p < .0001). Placebo-adjusted mean changes in fasting plasma glucose (-40.1 mg/dl) and body weight (-2.5 kg) at week 24 were statistically significant (p < .0001). In addition, a significant decrease in blood pressure, low-density lipoprotein cholesterol, triglyceride, and homeostasis model assessment of insulin resistance were observed, along with a significant increase in high-density lipoprotein cholesterol. No significant increase in treatment-related adverse events was observed for enavogliflozin. CONCLUSIONS: Monotherapy with enavogliflozin 0.3 mg improved glycaemic control in people with T2DM. Enavogliflozin therapy also exerted beneficial effects on body weight, blood pressure and lipid profile.
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Diabetes Mellitus Tipo 2 , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Humanos , Glucemia , Peso Corporal , Colesterol , Método Doble Ciego , Hemoglobina Glucada , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/uso terapéutico , Lípidos , República de Corea/epidemiología , Inhibidores del Cotransportador de Sodio-Glucosa 2/efectos adversos , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Resultado del TratamientoRESUMEN
Neurexins (Nrxns) and LAR-RPTPs (leukocyte common antigen-related protein tyrosine phosphatases) are presynaptic adhesion proteins responsible for organizing presynaptic machineries through interactions with nonoverlapping extracellular ligands. Here, we report that two members of the LAR-RPTP family, PTPσ and PTPδ, are required for the presynaptogenic activity of Nrxns. Intriguingly, Nrxn1 and PTPσ require distinct sets of intracellular proteins for the assembly of specific presynaptic terminals. In addition, Nrxn1α showed robust heparan sulfate (HS)-dependent, high-affinity interactions with Ig domains of PTPσ that were regulated by the splicing status of PTPσ. Furthermore, Nrxn1α WT, but not a Nrxn1α mutant lacking HS moieties (Nrxn1α ΔHS), inhibited postsynapse-inducing activity of PTPσ at excitatory, but not inhibitory, synapses. Similarly, cis expression of Nrxn1α WT, but not Nrxn1α ΔHS, suppressed the PTPσ-mediated maintenance of excitatory postsynaptic specializations in mouse cultured hippocampal neurons. Lastly, genetics analyses using male or female Drosophila Dlar and Dnrx mutant larvae identified epistatic interactions that control synapse formation and synaptic transmission at neuromuscular junctions. Our results suggest a novel synaptogenesis model whereby different presynaptic adhesion molecules combine with distinct regulatory codes to orchestrate specific synaptic adhesion pathways.SIGNIFICANCE STATEMENT We provide evidence supporting the physical interactions of neurexins with leukocyte common-antigen related receptor tyrosine phosphatases (LAR-RPTPs). The availability of heparan sulfates and alternative splicing of LAR-RPTPs regulate the binding affinity of these interactions. A set of intracellular presynaptic proteins is involved in common for Nrxn- and LAR-RPTP-mediated presynaptic assembly. PTPσ triggers glutamatergic and GABAergic postsynaptic differentiation in an alternative splicing-dependent manner, whereas Nrxn1α induces GABAergic postsynaptic differentiation in an alternative splicing-independent manner. Strikingly, Nrxn1α inhibits the glutamatergic postsynapse-inducing activity of PTPσ, suggesting that PTPσ and Nrxn1α might control recruitment of a different pool of postsynaptic machinery. Drosophila orthologs of Nrxns and LAR-RPTPs mediate epistatic interactions in controlling synapse structure and strength at neuromuscular junctions, underscoring the physiological significance in vivo.
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Proteínas de Unión al Calcio/fisiología , Antígenos Comunes de Leucocito/fisiología , Moléculas de Adhesión de Célula Nerviosa/fisiología , Animales , Proteínas de Unión al Calcio/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster , Potenciales Postsinápticos Excitadores/fisiología , Espacio Extracelular/metabolismo , Femenino , Células HEK293 , Humanos , Larva , Masculino , Ratones , Conformación Molecular , Moléculas de Adhesión de Célula Nerviosa/metabolismo , Embarazo , Terminales Presinápticos/metabolismo , Ratas , Proteínas Tirosina Fosfatasas Similares a Receptores/genética , Transmisión Sináptica/fisiologíaRESUMEN
Leukocyte common antigen-receptor protein tyrosine phosphatases (LAR-RPTPs) are hub proteins that organize excitatory and inhibitory synapse development through binding to various extracellular ligands. Here, we report that knockdown (KD) of the LAR-RPTP family member PTPσ reduced excitatory synapse number and transmission in cultured rat hippocampal neurons, whereas KD of PTPδ produced comparable decreases at inhibitory synapses, in both cases without altering expression levels of interacting proteins. An extensive series of rescue experiments revealed that extracellular interactions of PTPσ with Slitrks are important for excitatory synapse development. These experiments further showed that the intracellular D2 domain of PTPσ is required for induction of heterologous synapse formation by Slitrk1 or TrkC, suggesting that interaction of LAR-RPTPs with distinct intracellular presynaptic proteins, drives presynaptic machinery assembly. Consistent with this, double-KD of liprin-α2 and -α3 or KD of PTPσ substrates (N-cadherin and p250RhoGAP) in neurons inhibited Slitrk6-induced, PTPσ-mediated heterologous synapse formation activity. We propose a synaptogenesis model in presynaptic neurons involving LAR-RPTP-organized retrograde signaling cascades, in which both extracellular and intracellular mechanisms are critical in orchestrating distinct synapse types.SIGNIFICANCE STATEMENT In this study, we sought to test the unproven hypothesis that PTPσ and PTPδ are required for excitatory and inhibitory synapse formation/transmission, respectively, in cultured hippocampal neurons, using knockdown-based loss-of-function analyses. We further performed extensive structure-function analyses, focusing on PTPσ-mediated actions, to address the mechanisms of presynaptic assembly at excitatory synaptic sites. Using interdisciplinary approaches, we systematically applied a varied set of PTPσ deletion variants, point mutants, and splice variants to demonstrate that both extracellular and intracellular mechanisms are involved in organizing presynaptic assembly. Strikingly, extracellular interactions of PTPσ with heparan sulfates and Slitrks, intracellular interactions of PTPσ with liprin-α and its associated proteins through the D2 domain, as well as distinct substrates are all critical.
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Neurogénesis/fisiología , Proteínas Tirosina Fosfatasas Clase 2 Similares a Receptores/metabolismo , Sinapsis/fisiología , Transmisión Sináptica/fisiología , Animales , Humanos , Neuronas/fisiología , Ratas , Transducción de Señal/fisiologíaRESUMEN
Parkinson's disease (PD) is characterized by slow, progressive degeneration of dopaminergic neurons in the substantia nigra. The cause of neuronal death in PD is largely unknown, but several genetic loci, including leucine-rich repeat kinase 2 (LRRK2), have been identified. LRRK2 has guanosine triphosphatase (GTPase) and kinase activities, and mutations in LRRK2 are the major cause of autosomal-dominant familial PD. Histone deacetylases (HDACs) remove acetyl groups from lysine residues on histone tails, promoting transcriptional repression via condensation of chromatin. Here, we demonstrate that LRRK2 binds to and directly phosphorylates HDAC3 at Ser-424, thereby stimulating HDAC activity. Specifically, LRRK2 promoted the deacetylation of Lys-5 and Lys-12 on histone H4, causing repression of gene transcription. Moreover, LRRK2 stimulated nuclear translocation of HDAC3 via the phoshorylation of karyopherin subunit α2 and α6. HDAC3 phosphorylation and its nuclear translocation were increased in response to 6-hydroxydopamine (6-OHDA) treatment. LRRK2 also inhibited myocyte-specific enhancer factor 2D activity, which is required for neuronal survival. LRRK2 ultimately promoted 6-OHDA-induced cell death via positive modulation of HDAC3. These findings suggest that LRRK2 affects epigenetic histone modification and neuronal survival by facilitating HDAC3 activity and regulating its localization.
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Encéfalo/patología , Neuronas Dopaminérgicas/patología , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/metabolismo , Neuritas/patología , Neuroblastoma/patología , Acetilación , Animales , Encéfalo/metabolismo , Supervivencia Celular , Células Cultivadas , Neuronas Dopaminérgicas/metabolismo , Embrión de Mamíferos/metabolismo , Embrión de Mamíferos/patología , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Células HEK293 , Histona Desacetilasas/genética , Humanos , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , Ratones , Ratones Noqueados , Ratones Transgénicos , Neuritas/metabolismo , Neuroblastoma/metabolismo , Fosforilación , RatasRESUMEN
AIM: To evaluate the efficacy and safety of ipragliflozin vs placebo as add-on therapy to metformin and sitagliptin in Korean patients with type 2 diabetes mellitus (T2DM). METHODS: This double-blind, placebo-controlled, multi-centre, phase III study was conducted in Korea in 2015 to 2017. Patients were randomized to receive either ipragliflozin 50 mg/day or placebo once daily for 24 weeks in addition to metformin and sitagliptin. The primary endpoint was the change in glycated haemoglobin (HbA1c) from baseline to end of treatment (EOT). RESULTS: In total, 143 patients were randomized and 139 were included in efficacy analyses (ipragliflozin: 73, placebo: 66). Baseline mean (SD) HbA1c levels were 7.90 (0.69)% for ipragliflozin add-on and 7.92 (0.79)% for placebo. The corresponding mean (SD) changes from baseline to EOT were -0.79 (0.59)% and 0.03 (0.84)%, respectively, in favour of ipragliflozin (adjusted mean difference -0.83% [95% CI -1.07 to -0.59]; P < .0001). More ipragliflozin-treated patients than placebo-treated patients achieved HbA1c target levels of <7.0% (44.4% vs 12.1%) and < 6.5% (12.5% vs 1.5%) at EOT (P < .05 for both). Fasting plasma glucose, fasting serum insulin, body weight and homeostatic model assessment of insulin resistance decreased significantly at EOT, in favour of ipragliflozin (adjusted mean difference -1.64 mmol/L, -1.50 µU/mL, -1.72 kg, and -0.99, respectively; P < .05 for all). Adverse event rates were similar between groups (ipragliflozin: 51.4%; placebo: 50.0%). No previously unreported safety concerns were noted. CONCLUSIONS: Ipragliflozin as add-on to metformin and sitagliptin significantly improved glycaemic variables and demonstrated a good safety profile in Korean patients with inadequately controlled T2DM.
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Diabetes Mellitus Tipo 2/tratamiento farmacológico , Glucósidos/administración & dosificación , Metformina/administración & dosificación , Fosfato de Sitagliptina/administración & dosificación , Tiofenos/administración & dosificación , Adulto , Anciano , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/sangre , Método Doble Ciego , Quimioterapia Combinada , Femenino , Glucósidos/efectos adversos , Hemoglobina Glucada/efectos de los fármacos , Hemoglobina Glucada/metabolismo , Humanos , Masculino , Metformina/efectos adversos , Persona de Mediana Edad , República de Corea , Fosfato de Sitagliptina/efectos adversos , Tiofenos/efectos adversos , Resultado del Tratamiento , Adulto JovenRESUMEN
UNLABELLED: Neurotrophin-3 (NT-3) is a secreted neurotrophic factor that binds neurotrophin receptor tyrosine kinase C (TrkC), which in turn binds to presynaptic protein tyrosine phosphatase σ (PTPσ) to govern excitatory synapse development. However, whether and how NT-3 cooperates with the TrkC-PTPσ synaptic adhesion pathway and TrkC-mediated intracellular signaling pathways in rat cultured neurons has remained unclear. Here, we report that NT-3 enhances TrkC binding affinity for PTPσ. Strikingly, NT-3 treatment bidirectionally regulates the synaptogenic activity of TrkC: at concentrations of 10-25 ng/ml, NT-3 further enhanced the increase in synapse density induced by TrkC overexpression, whereas at higher concentrations, NT-3 abrogated TrkC-induced increases in synapse density. Semiquantitative immunoblotting and optogenetics-based imaging showed that 25 ng/ml NT-3 or light stimulation at a power that produced a comparable level of NT-3 (6.25 µW) activated only extracellular signal-regulated kinase (ERK) and Akt, whereas 100 ng/ml NT-3 (light intensity, 25 µW) further triggered the activation of phospholipase C-γ1 and CREB independently of PTPσ. Notably, disruption of TrkC intracellular signaling pathways, extracellular ligand binding, or kinase activity by point mutations compromised TrkC-induced increases in synapse density. Furthermore, only sparse, but not global, TrkC knock-down in cultured rat neurons significantly decreased synapse density, suggesting that intercellular differences in TrkC expression level are critical for its synapse-promoting action. Together, our data demonstrate that NT-3 is a key factor in excitatory synapse development that may direct higher-order assembly of the TrkC/PTPσ complex and activate distinct intracellular signaling cascades in a concentration-dependent manner to promote competition-based synapse development processes. SIGNIFICANCE STATEMENT: In this study, we present several lines of experimental evidences to support the conclusion that neurotrophin-3 (NT-3) modulates the synaptic adhesion pathway involving neurotrophin receptor tyrosine kinase C (TrkC) and presynaptic protein tyrosine phosphatase σ (PTPσ) in a bidirectional manner at excitatory synapses. NT-3 acts in concentration-independent manner to facilitate TrkC-mediated presynaptic differentiation, whereas it acts in a concentration-dependent manner to exert differential effects on TrkC-mediated organization of postsynaptic development. We further investigated TrkC extracellular ligand binding, intracellular signaling pathways, and kinase activity in NT-3-induced synapse development. Last, we found that interneuronal differences in TrkC levels regulate the synapse number. Overall, these results suggest that NT-3 functions as a positive modulator of synaptogenesis involving TrkC and PTPσ.
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Neurotrofina 3/metabolismo , Receptor trkC/metabolismo , Proteínas Tirosina Fosfatasas Clase 2 Similares a Receptores/metabolismo , Sinapsis/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Hipocampo , Neuronas/fisiología , Unión Proteica , Ratas , Proteínas Tirosina Fosfatasas Clase 2 Similares a Receptores/genética , Transducción de Señal/efectos de los fármacos , Sinapsis/fisiologíaRESUMEN
BACKGROUND: Gemigliptin is a new dipeptidyl peptidase-IV inhibitor. We investigated the efficacy and safety of initial combination therapy with gemigliptin and metformin compared with monotherapy with either drug in patients with type 2 diabetes (T2D). METHODS: A total of 433 T2D patients with a glycosylated haemoglobin (HbA1c) level of 7.5% to 11.0% and a fasting plasma glucose (FPG) concentration <270 mg/dL were randomly assigned to 3 groups: (1) gemigliptin 50 mg qd + metformin 1000 to 2000 mg qd (titrated individually), (2) gemigliptin 50 mg qd, or (3) metformin 1000 to 2000 mg qd. The primary end-point was the change in HbA1c level after 24 weeks. Secondary end-points were the changes in FPG, insulin, proinsulin and C-peptide levels. The percentages of responders who achieved an HbA1c level <7% (or <6.5%) were compared between treatment groups. RESULTS: Baseline HbA1c levels were 8.7% in all groups. The mean changes in HbA1c level from baseline to week 24 were -2.06%, -1.24% and -1.47% in the combination, gemigliptin monotherapy and metformin monotherapy groups, respectively. The 95% confidence intervals for between-group differences in HbA1c changes were -1.02 to -0.63 in the combination group vs the gemigliptin group and -0.82 to -0.41 vs the metformin group, which confirmed the superiority of combination therapy. A significantly higher percentage of patients in the combination therapy group reached the target HbA1c level <7% (or <6.5%) compared with the monotherapy groups. No severe side effects were observed. CONCLUSIONS: In T2D patients, the initial combination of gemigliptin and metformin had superior efficacy without safety concerns compared with monotherapy with either drug.
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Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Hipoglucemiantes/uso terapéutico , Metformina/uso terapéutico , Piperidonas/uso terapéutico , Pirimidinas/uso terapéutico , Adulto , Anciano , Glucemia/metabolismo , Péptido C/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Método Doble Ciego , Quimioterapia Combinada , Ayuno , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Hipoglucemia/inducido químicamente , Insulina/metabolismo , Masculino , Persona de Mediana Edad , Proinsulina/metabolismo , República de Corea , Tailandia , Resultado del TratamientoRESUMEN
AIMS: To evaluate the efficacy and safety of evogliptin, a newly developed dipeptidyl peptidase-4 inhibitor, in patients with type 2 diabetes (T2D) inadequately controlled by diet and exercise. MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled, parallel-group, multicentre, phase III study, 160 patients with T2D were assigned to either evogliptin 5 mg or placebo for 24 weeks. The primary endpoint was the mean change in glycated haemoglobin (HbA1c) from baseline to week 24. RESULTS: The mean baseline HbA1c levels were similar in the evogliptin and the placebo groups (7.20% ± 0.56% vs 7.20% ± 0.63%, respectively). At week 24, evogliptin significantly reduced HbA1c levels from baseline compared with placebo (-0.23% vs 0.05%, respectively, P < .0001). Additionally, the proportion of patients achieving HbA1c <6.5% was significantly higher in the evogliptin group than in the placebo group (33.3% vs 15.2%; P = .008). The overall incidence of adverse events, including hypoglycaemia, was similar in the 2 groups. CONCLUSIONS: In this 24-week study, once-daily evogliptin monotherapy significantly improved glycaemic control and was well tolerated in patients with T2D.
Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Hemoglobina Glucada/análisis , Hiperglucemia/prevención & control , Hipoglucemia/prevención & control , Piperazinas/uso terapéutico , Anciano , Glucemia/análisis , Terapia Combinada/efectos adversos , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/terapia , Dieta para Diabéticos , Inhibidores de la Dipeptidil-Peptidasa IV/efectos adversos , Método Doble Ciego , Ejercicio Físico , Femenino , Humanos , Hipoglucemia/inducido químicamente , Resistencia a la Insulina , Perdida de Seguimiento , Masculino , Persona de Mediana Edad , Pacientes Desistentes del Tratamiento , Educación del Paciente como Asunto , Piperazinas/efectos adversosRESUMEN
AIMS: This trial consisted of a 24-week multicentre, randomized, double-blind, double-dummy, active-controlled study and a 52-week open label extension study to assess the efficacy and safety of evogliptin, a novel dipeptidyl peptidase-4 inhibitor, compared to sitagliptin in patients with type 2 diabetes who have inadequate glycaemic control with metformin alone. METHODS: Adult patients with type 2 diabetes mellitus (N = 222) with HbA1c 6.5% to 11% who were receiving stable doses of metformin (≥1000 mg/d) were randomized 1:1 to add-on evogliptin 5 mg (N = 112) or sitagliptin 100 mg (N = 110) once daily for 24 weeks. The primary efficacy analysis consisted of a comparison of the change from baseline HbA1c at week 24. Non-inferiority was concluded if the upper limit of the 2-sided 95% confidence interval for the HbA1c difference between treatments was <0.35%. RESULTS: Mean changes in HbA1c following addition of evogliptin or sitagliptin were -0.59% and -0.65%, respectively. The between-group difference was 0.06% (2-sided 95% confidence interval, -0.10 to 0.22), demonstrating non-inferiority. After the 52-week treatment, evogliptin caused a persistently decreased level of HbA1c (-0.44% ± 0.65%, P < .0001). In general, both treatments were well tolerated, with incidences and types of adverse events comparable between the two groups. Hypoglycaemic events, mostly mild, were reported in 0.9% of patients treated with evogliptin and in 2.8% of patients treated with sitagliptin for 24 weeks. CONCLUSIONS: Evogliptin 5 mg added to metformin therapy effectively improved glycaemic control and was non-inferior to sitagliptin and well tolerated in patients with type 2 diabetes mellitus that was inadequately controlled by metformin alone.
Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Hiperglucemia/prevención & control , Hipoglucemia/prevención & control , Piperazinas/uso terapéutico , Fosfato de Sitagliptina/uso terapéutico , Anciano , Diabetes Mellitus Tipo 2/sangre , Inhibidores de la Dipeptidil-Peptidasa IV/efectos adversos , Monitoreo de Drogas , Resistencia a Medicamentos , Quimioterapia Combinada/efectos adversos , Femenino , Estudios de Seguimiento , Hemoglobina Glucada/análisis , Humanos , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/uso terapéutico , Incidencia , Masculino , Metformina/efectos adversos , Metformina/uso terapéutico , Persona de Mediana Edad , Piperazinas/efectos adversos , República de Corea/epidemiología , Fosfato de Sitagliptina/efectos adversosRESUMEN
AIMS: To assess the efficacy and safety of gemigliptin, a dipeptidyl peptidase-4 inhibitor, added to metformin and sulphonylurea in patients with type 2 diabetes (T2DM). MATERIALS AND METHODS: We conducted a randomized, double-blind, placebo-controlled trial in 219 Korean patients inadequately controlled with metformin and glimepiride. Participants were randomized to gemigliptin 50 mg once daily or placebo added to metformin and glimepiride. The primary endpoint was change in glycated haemoglobin (HbA1c) level from baseline to week 24. RESULTS: The baseline HbA1c was 8.2% in both groups. The addition of gemigliptin to metformin and glimepiride significantly reduced HbA1c levels at week 24 compared with placebo (between-group difference in adjusted mean change -0.87%, 95% confidence interval [CI] -1.09% to -0.64%). Fasting plasma glucose level was also significantly reduced with gemigliptin (-0.93 mmol/L, 95% CI -1.50 to -0.35 mmol/L), and a higher proportion of participants achieved an HbA1c level of <7% (39.3% vs 5.5%; P <.001) in the gemigliptin group than in the placebo group. Total cholesterol and LDL cholesterol were modestly but significantly reduced in the gemigliptin group compared with the placebo group (-0.21 mmol/L, 95% CI -0.38 to -0.03 mmol/L for total cholesterol, -0.18 mmol/L, 95% CI -0.34 to -0.01 mmol/L for LDL cholesterol). The incidence of hypoglycaemia was 9.4% in the gemigliptin group and 2.7% in the placebo group. CONCLUSIONS: Gemigliptin significantly improved glycaemic control in patients with T2DM inadequately controlled with metformin and sulphonylurea. The incidence of hypoglycaemia was higher with gemigliptin than with placebo, which highlights the importance of optimal dose adjustment for sulphonylurea.
Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Resistencia a Medicamentos , Hiperglucemia/prevención & control , Hipoglucemia/prevención & control , Piperidonas/uso terapéutico , Pirimidinas/uso terapéutico , Anciano , Diabetes Mellitus Tipo 2/sangre , Inhibidores de la Dipeptidil-Peptidasa IV/efectos adversos , Método Doble Ciego , Monitoreo de Drogas , Quimioterapia Combinada/efectos adversos , Femenino , Hemoglobina Glucada/análisis , Humanos , Hipoglucemia/inducido químicamente , Hipoglucemia/epidemiología , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/uso terapéutico , Incidencia , Masculino , Metformina/efectos adversos , Metformina/uso terapéutico , Persona de Mediana Edad , Piperidonas/efectos adversos , Pirimidinas/efectos adversos , República de Corea/epidemiología , Riesgo , Compuestos de Sulfonilurea/efectos adversos , Compuestos de Sulfonilurea/uso terapéuticoRESUMEN
OBJECTIVE: To determine the effect of probucol on urine albumin excretion in type 2 diabetes mellitus patients with albuminuria using angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. APPROACH AND RESULTS: This was a 16-week, phase II, randomized, placebo-controlled, parallel-group study in type 2 diabetes mellitus patients with a urinary albumin/creatinine ratio of ≥300 mg/g using angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, conducted in 17 tertiary referral hospitals. Eligible patients were randomized to probucol 250 mg/d (n=44), probucol 500 mg/d (n=41), and placebo (n=41) groups in a ratio of 1:1:1 after block randomization procedures, keeping the treatment assignment blinded to the investigators, patients, and study assistants. The primary end point was change in the geometric mean of urinary albumin/creatinine ratio from baseline to week 16 (ClinicalTrials.gov identifier NCT01726816). The study was started on November 8, 2012, and completed on March 24, 2014. The least squares mean change±SE from baseline in urinary albumin/creatinine ratio at week 16 was -7.2±639.5 mg/g in the probucol 250 mg/d group (n=43; P=0.2077 versus placebo group), 9.3±587.4 mg/g in the probucol 500 mg/d group (n=40; P=0.1975 versus placebo group), and 259.0±969.1 mg/g in the placebo group (n=41). Although the majority of subjects were on statins, probucol treatment significantly lowered total cholesterol and low-density lipoprotein cholesterol levels. QT prolongation occurred in one and two subjects in control and probucol 250 mg/d groups, respectively. CONCLUSIONS: Four months of probucol up to 500 mg/d failed to reduce urinary albumin excretion.
Asunto(s)
Albuminuria/tratamiento farmacológico , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Anticolesterolemiantes/uso terapéutico , Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/tratamiento farmacológico , Dislipidemias/tratamiento farmacológico , Riñón/efectos de los fármacos , Probucol/uso terapéutico , Sistema Renina-Angiotensina/efectos de los fármacos , Adulto , Anciano , Albuminuria/diagnóstico , Albuminuria/etiología , Albuminuria/fisiopatología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/efectos adversos , Inhibidores de la Enzima Convertidora de Angiotensina/efectos adversos , Anticolesterolemiantes/efectos adversos , Biomarcadores/sangre , LDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/diagnóstico , Nefropatías Diabéticas/diagnóstico , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/fisiopatología , Método Doble Ciego , Dislipidemias/sangre , Dislipidemias/complicaciones , Dislipidemias/diagnóstico , Femenino , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Riñón/fisiopatología , Lipoproteínas LDL/sangre , Masculino , Persona de Mediana Edad , Probucol/efectos adversos , República de Corea , Centros de Atención Terciaria , Factores de Tiempo , Resultado del TratamientoRESUMEN
This study examined whether the existing duration of type-2 diabetes influenced patient responses to progressive resistance training. Twenty-six women with type-2 diabetes were stratified into short- (3 ± 2 years; n = 12) or long-standing (10 ± 3 years; n = 14) disease groups. Patients participated in a high daily or high weekly frequency elastic band resistance training program that consisted of 2 daily sessions, 5 d·wk for 12 weeks. Glucose control, body composition, and physical function were evaluated pre- and posttraining. No significant diabetes duration × training interactions were detected for blood markers of glucose control (p > 0.05); however, there were significant main effects of training driven by comparable improvements in both cohorts (hemoglobin A1c, -13 to 18%; fasting glucose, -23 to 31%; postprandial glucose, -36 to 40%; insulin, -34 to 40%; C-peptide, -38 to 51%; p ≤ 0.05). Anthropometrics and body composition were also favorably modified in both the groups after training (weight, -5 to 9%; body mass index, -6 to 9%; waist-to-hip ratio, -3 to 5%; percent fat, -14 to 20%; p ≤ 0.05). Likewise, indices of physical function improved in both the groups after training (bicep curl repetitions, +15-33%; sit-and-stand repetitions, +45-47%; p ≤ 0.05). A few exceptions were noted in which patients with long-standing disease demonstrated greater pre-to-post gains (p ≤ 0.05) in grip strength (+11-13%) and peak exercise time (+19%) and load (+21%) during graded exercise, whereas those with shorter disease duration did not. Overall, these data suggest that patients with a long history of diabetes respond positively to resistance training and in a manner comparable to their recently diagnosed counterparts. Therefore, current inactivity in patients with long-standing disease should not deter from beginning an exercise program.
Asunto(s)
Glucemia/metabolismo , Composición Corporal/fisiología , Diabetes Mellitus Tipo 2/terapia , Ejercicio Físico/fisiología , Entrenamiento de Fuerza/métodos , Anciano , Antropometría , Biomarcadores/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Impedancia Eléctrica , Prueba de Esfuerzo , Femenino , Hemodinámica/fisiología , Humanos , Persona de Mediana Edad , Factores de TiempoRESUMEN
LAR-RPTPs are evolutionarily conserved presynaptic cell-adhesion molecules that orchestrate multifarious synaptic adhesion pathways. Extensive alternative splicing of LAR-RPTP mRNAs may produce innumerable LAR-RPTP isoforms that act as regulatory "codes" for determining the identity and strength of specific synapse signaling. However, no direct evidence for this hypothesis exists. Here, using targeted RNA sequencing, we detected LAR-RPTP mRNAs in diverse cell types across adult male mouse brain areas. We found pronounced cell-type-specific patterns of two microexons, meA and meB, in Ptprd mRNAs. Moreover, diverse neural circuits targeting the same neuronal populations were dictated by the expression of different Ptprd variants with distinct inclusion patterns of microexons. Furthermore, conditional ablation of Ptprd meA+ variants at presynaptic loci of distinct hippocampal circuits impaired distinct modes of synaptic transmission and objection-location memory. Activity-triggered alterations of the presynaptic Ptprd meA code in subicular neurons mediates NMDA receptor-mediated postsynaptic responses in CA1 neurons and objection-location memory. Our data provide the evidence of cell-type- and/or circuit-specific expression patterns in vivo and physiological functions of LAR-RPTP microexons that are dynamically regulated.
Asunto(s)
Sinapsis , Transmisión Sináptica , Ratones , Animales , Masculino , Transmisión Sináptica/fisiología , Sinapsis/metabolismo , Transducción de Señal , Neuronas/metabolismo , Moléculas de Adhesión Celular/metabolismo , Proteínas Tirosina Fosfatasas Clase 2 Similares a Receptores/metabolismo , ARN Mensajero/metabolismoRESUMEN
Background: This study assessed the efficacy and safety of triple therapy with pioglitazone 15 mg add-on versus placebo in patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin and dapagliflozin. Methods: In this multicenter, double-blind, randomized, phase 3 study, patients with T2DM with an inadequate response to treatment with metformin (≥1,000 mg/day) plus dapagliflozin (10 mg/day) were randomized to receive additional pioglitazone 15 mg/day (n=125) or placebo (n=125) for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin (HbA1c) levels from baseline to week 24 (ClinicalTrials.gov identifier: NCT05101135). Results: At week 24, the adjusted mean change from baseline in HbA1c level compared with placebo was significantly greater with pioglitazone treatment (-0.47%; 95% confidence interval, -0.61 to -0.33; P<0.0001). A greater proportion of patients achieved HbA1c <7% or <6.5% at week 24 with pioglitazone compared to placebo as add-on to 10 mg dapagliflozin and metformin (56.8% vs. 28% for HbA1c <7%, and 23.2% vs. 9.6% for HbA1c <6.5%; P<0.0001 for all). The addition of pioglitazone also significantly improved triglyceride, highdensity lipoprotein cholesterol levels, and homeostatic model assessment of insulin resistance levels, while placebo did not. The incidence of treatment-emergent adverse events was similar between the groups, and the incidence of fluid retention-related side effects by pioglitazone was low (1.5%). Conclusion: Triple therapy with the addition of 15 mg/day of pioglitazone to dapagliflozin plus metformin was well tolerated and produced significant improvements in HbA1c in patients with T2DM inadequately controlled with dapagliflozin plus metformin.
RESUMEN
Background: Guidelines for switching to triple combination therapy directly after monotherapy failure are limited. This study investigated the efficacy, long-term sustainability, and safety of either mono or dual add-on therapy using alogliptin and pioglitazone for patients with type 2 diabetes mellitus (T2DM) who did not achieve their target glycemic range with metformin monotherapy. Methods: The Practical Evidence of Antidiabetic Combination Therapy in Korea (PEAK) was a multicenter, placebo-controlled, double-blind, randomized trial. A total of 214 participants were randomized to receive alogliptin+pioglitazone (Alo+Pio group, n=70), alogliptin (Alo group, n=75), or pioglitazone (Pio group, n=69). The primary outcome was the difference in glycosylated hemoglobin (HbA1c) levels between the three groups at baseline to 24 weeks. For durability, the achievement of HbA1c levels <7% and <6.5% was compared in each group. The number of adverse events was investigated for safety. Results: After 24 weeks of treatment, the change of HbA1c in the Alo+Pio, Alo, and Pio groups were -1.38%±0.08%, -1.03%±0.08%, and -0.84%±0.08%, respectively. The Alo+Pio group had significantly lower HbA1c levels than the other groups (P=0.0063, P<0.0001) and had a higher proportion of patients with target HbA1c achievement. In addition, insulin sensitivity and ß-cell function, lipid profiles, and other metabolic indicators were also improved. There were no significant safety issues in patients treated with triple combination therapy. Conclusion: Early combination triple therapy showed better efficacy and durability than the single add-on (dual) therapy. Therefore, combination therapy with metformin, alogliptin, and pioglitazone is a valuable early treatment option for T2DM poorly controlled with metformin monotherapy.