The unconventional prefoldin RPB5 interactor mediates the gravitropic response by modulating cytoskeleton organization and auxin transport in Arabidopsis.

Gravity-induced root curvature involves the asymmetric distribution of the phytohormone auxin. This response depends on the concerted activities of the auxin transporters such as PIN-FORMED (PIN) proteins for auxin efflux and AUXIN RESISTANT 1 (AUX1) for auxin influx. However, how the auxin gradient is established remains elusive. Here we identified a new mutant with a short root, strong auxin distribution in the lateral root cap and an impaired gravitropic response. The causal gene encoded an Arabidopsis homolog of the human unconventional prefoldin RPB5 interactor (URI). AtURI interacted with prefoldin 2 (PFD2) and PFD6, two ß-type PFD members that modulate actin and tubulin patterning in roots. The auxin reporter DR5rev :GFP showed that asymmetric auxin redistribution after gravistimulation is disordered in aturi-1 root tips. Treatment with the endomembrane protein trafficking inhibitor brefeldin A indicated that recycling of the auxin transporter PIN2 is disrupted in aturi-1 roots as well as in pfd mutants. We propose that AtURI cooperates with PFDs to recycle PIN2 and modulate auxin distribution.

Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE8 and CATALASE3 Function in Abscisic Acid-Mediated Signaling and H2O2 Homeostasis in Stomatal Guard Cells under Drought Stress.

Drought is a major threat to plant growth and crop productivity. Calcium-dependent protein kinases (CDPKs, CPKs) are believed to play important roles in plant responses to drought stress. Here, we report that Arabidopsis thaliana CPK8 functions in abscisic acid (ABA)- and Ca(2+)-mediated plant responses to drought stress. The cpk8 mutant was more sensitive to drought stress than wild-type plants, while the transgenic plants overexpressing CPK8 showed enhanced tolerance to drought stress compared with wild-type plants. ABA-, H2O2-, and Ca(2+)-induced stomatal closing were impaired in cpk8 mutants. Arabidopsis CATALASE3 (CAT3) was identified as a CPK8-interacting protein, confirmed by yeast two-hybrid, coimmunoprecipitation, and bimolecular fluorescence complementation assays. CPK8 can phosphorylate CAT3 at Ser-261 and regulate its activity. Both cpk8 and cat3 plants showed lower catalase activity and higher accumulation of H2O2 compared with wild-type plants. The cat3 mutant displayed a similar drought stress-sensitive phenotype as cpk8 mutant. Moreover, ABA and Ca(2+) inhibition of inward K(+) currents were diminished in guard cells of cpk8 and cat3 mutants. Together, these results demonstrated that CPK8 functions in ABA-mediated stomatal regulation in responses to drought stress through regulation of CAT3 activity.

The role of Arabidopsis Actin-Related Protein 3 in amyloplast sedimentation and polar auxin transport in root gravitropism.

Gravitropism is vital for shaping directional plant growth in response to the forces of gravity. Signals perceived in the gravity-sensing cells can be converted into biochemical signals and transmitted. Sedimentation of amyloplasts in the columella cells triggers asymmetric auxin redistribution in root tips, leading to downward root growth. The actin cytoskeleton is thought to play an important role in root gravitropism, although the molecular mechanism has not been resolved. DISTORTED1 (DIS1) encodes the ARP3 subunit of the Arabidopsis Actin-Related Protein 2/3 (ARP2/3) complex, and the ARP3/DIS1 mutant dis1-1 showed delayed root curvature after gravity stimulation. Microrheological analysis revealed that the high apparent viscosity within dis1-1 central columella cells is closely associated with abnormal movement trajectories of amyloplasts. Analysis using a sensitive auxin input reporter DII-VENUS showed that asymmetric auxin redistribution was reduced in the root tips of dis1-1, and the actin-disrupting drug Latrunculin B increased the asymmetric auxin redistribution. An uptake assay using the membrane-selective dye FM4-64 indicated that endocytosis was decelerated in dis1-1 root epidermal cells. Treatment and wash-out with Brefeldin A, which inhibits protein transport from the endoplasmic reticulum to the Golgi apparatus, showed that cycling of the auxin-transporter PIN-FORMED (PIN) proteins to the plasma membrane was also suppressed in dis1-1 roots. The results reveal that ARP3/DIS1 acts in root gravitropism by affecting amyloplast sedimentation and PIN-mediated polar auxin transport through regulation of PIN protein trafficking.

CD8(+) T cell-mediated cytotoxicity toward Schwann cells promotes diabetic peripheral neuropathy.

BACKGROUND: Damage to Schwann cells has been reported in the development of diabetic peripheral neuropathy (DPN), but how Schwann cells are damaged has not been elucidated. METHODS: The highly expressed proteins in the PBMC of DPN patients were identified through MALDI-TOF/TOF and SELDI protein chip technology. The expression levels of CXCR3 were detected by qPCR and flow cytometric analysis. Transwell migration assay was to investigate the migration of CD8(+) T cells. Western-blot analysis was to detect the levels of p38 MAP kinases pathway related proteins and TNF-α, FasL, and PDL1. RESULTS: Two highly expressed proteins, CXCR3 and p38, were identified. Under high glucose conditions, CXCR3 was elevated in CD8(+) T cells via the activation of p38 MAP kinases. Moreover, CXCL9, CXCL10, and CXCL11 expression were induced in Schwann cells, leading to the recruitment and infiltration of CD8(+) T cells into DPN tissues. Further study demonstrated that Schwann cells promoted activation of CD8(+) T cells and induced expression of TNF-α, FasL, and PDL1 on CD8(+) T cells, in return, CD8(+) T cells induced obvious apoptosis of Schwann cells. CONCLUSION: Our study indicates that CD8(+) T cells mediate cytotoxicity toward Schwann cells and play an important role in the development of DPN.

Self-Assembled Corrole/Chitosan Photothermal Nanoparticles for Accelerating Infected Diabetic Wound Healing.

Microvascular dysfunction caused by hyperglycemia leads to slow healing of diabetic wounds and significantly increases the risk of bacterial infection. The misuse of antibiotics can also lead to bacterial resistance, making the management of diabetic wounds more challenging. Thus, developing new antibacterial agents or strategies to overcome antibiotic resistance is highly pursued. Herein, novel supramolecular photothermal nanoparticles (MCC/CS NPs), assembled from mono-carboxyl corrole (MCC) and chitosan via hydrogen bonding and π-π stacking, are developed and used for treating bacterial wound infection. The MCC molecules possess good photothermal performance and the chitosan with inherent bioactivity can exert moderate antibacterial effects. The aggregation of MCC in MCC/CS NPs induced by chitosan-templated self-assembly further quenches molecular fluorescence and realizes an extraordinary photothermal conversion efficiency of 66.4%. Moreover, the highly positively charged MCC/CS NPs can selectively target bacteria via electrostatic interactions. Under near-infrared laser irradiation, the MCC/CS NPs achieve potent photothermal and inherent antimicrobial synergistic effects against Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) in vitro. Furthermore, the bacteria-infected diabetic wound model confirms that the MCC/CS NPs can effectively kill drug-resistant bacteria, accelerate wound healing and angiogenesis, and show good biocompatibility, representing a novel and efficient photothermal antibacterial nanoplatform.

Engineered MOF-Enzyme Nanocomposites for Tumor Microenvironment-Activated Photodynamic Therapy with Self-Luminescence and Oxygen Self-Supply.

Photodynamic therapy (PDT) is a promising strategy for cancer treatment. However, its efficiency is hindered by three key parameters, namely, limited penetration depth of external light, tumor hypoxia, and self-aggregation of photosensitizers. Herein, we fabricated a novel "all-in-one" chemiluminescence-PDT nanosystem through the integration of an oxygen-supplying protein (hemoglobin, Hb) and a luminescent donor (luminol, Lum) in hierarchically engineered mesoporous porphyrinic metal-organic framework (MOF) nanoparticles. Mechanistically, the in situ chemiluminescence of Lum is activated by the high concentration of H2O2 in 4T1 cancer cells and further catalyzed by Hb and then absorbed by the porphyrin ligands in MOF nanoparticles through chemiluminescence resonance energy transfer. The excited porphyrins then sensitize oxygen supplied by Hb to produce sufficient reactive oxygen species that kill cancer cells. The MOF-based nanocomposite demonstrates excellent anticancer activity both in vitro and in vivo, with eventually a 68.1% tumor inhibition rate after intravenous injections without external light irradiation. This self-illuminating, oxygen-self-supplying nanosystem integrates all essential components of PDT into one simple nanoplatform, demonstrating great potential for the selective phototherapy of deep-seated cancer.

Efficient oral insulin delivery enabled by transferrin-coated acid-resistant metal-organic framework nanoparticles.

Oral protein delivery is considered a cutting-edge technology to improve patients' quality of life, offering superior patient compliance and convenience compared with injections. However, oral protein formulation has stagnated because of the instability and inefficient penetration of protein in the gastrointestinal tract. Here, we used acid-resistant metal-organic framework nanoparticles (UiO-68-NH2) to encapsulate sufficient insulin and decorated the exterior with targeting proteins (transferrin) to realize highly efficient oral insulin delivery. The UiO-68-NH2 nanocarrier with proper pore size achieved high insulin loading while protecting insulin from acid and enzymatic degradation. Through receptor-mediated transcellular pathway, the transferrin-coated nanoparticles realized efficient transport across the intestinal epithelium and controlled insulin release under physiological conditions, leading to a notable hypoglycemic effect and a high oral bioavailability of 29.6%. Our work demonstrates that functional metal-organic framework nanoparticles can protect proteins from the gastric environment and overcome the intestinal barrier, thus providing the possibility for oral biomacromolecule delivery.

Stimuli-responsive charge-reversal MOF@polymer hybrid nanocomposites for enhanced co-delivery of chemotherapeutics towards combination therapy of multidrug-resistant cancer.

Combination chemotherapy is a promising strategy for cancer treatment in clinics especially when multidrug-resistant cancer is emerging. One significant challenge remains in achieving sufficient multi-drug delivery into tumor cells to maximize the synergetic therapeutic effect, as it is hard to concentrate drugs in drug-resistant cancer. Therefore herein, metal-organic framework (MOF)-based polymer-coated hybrid nanoparticles (NPs) were devised and constructed for the co-delivery of doxorubicin and cisplatin to enhance combination therapy of multidrug-resistant cancer. The MOF@polymer nanocarrier combined the merits of high multi-drug loading capacity, physiological stability, and tumor microenvironment pH-responsiveness, facilitating simultaneous delivery of drugs into cancer cells and making the most of synergistic antitumor effect. Remarkably, this hybrid nanocarrier maintains a negative surface charge during circulation to guarantee a stable and prolonged process in vivo, and then exposes inner positive MOF after degradation of the outer polymer in the acidic tumor microenvironment to promote multi-drug release, cellular internalization, nuclear localization, and tumor penetration. In vitro and in vivo studies with drug-resistant MCF-7/ADR cancer suggested that the nanocarrier could achieve increased accumulation of drugs in solid tumors, remarkable tumor elimination results as well as minimized side effects, indicating an improved efficacy and safety of combination chemotherapy. MOF@polymer hybrid nanocarriers provide new insights into the development of stimuli-responsive co-delivery systems of multiple drugs.

Biomimetic nanoparticles: U937 cell membranes based core-shell nanosystems for targeted atherosclerosis therapy.

Atherosclerosis (AS), with its intricate pathogenesis, is primarily responsible for the development and progression of cardiovascular diseases. Although drug development has made some achievements in AS therapy, limited targeting ability and rapid blood clearance remain great challenges for achieving superior clinical outcomes. Herein, ginsenoside (Re)- and catalase (CAT)-coloaded porous poly(lactic-coglycolic acid) (PLGA) nanoparticles (NPs) were prepared and then surface modified with U937 cell membranes (UCMs) to yield a dual targeted model and multimechanism treatment biomimetic nanosystem (Cat/Re@PLGA@UCM). The nanoparticles consisted of a core-shell spherical morphology with a favorable size of 112.7 ± 0.4 nm. Furthermore, UCM assisted the nanosystem in escaping macrophage phagocytosis and targeting atherosclerotic plaques. Meanwhile, loading with catalase might not only exhibit favorable antioxidant effects but also enable H2O2-responsive drug release ability. The Cat/Re@PLGA@UCM NPs also exhibited outstanding ROS scavenging properties, downregulating ICAM-1, TNF-α and IL-1ß, while preventing angiogenesis to attenuate the progression of AS. Moreover, the nanodrugs displayed 2.7-fold greater efficiency in reducing the atherosclerotic area in ApoE-/- mouse models compared to free Re. Our nanoformulation also displayed excellent biosafety in response to long-term administration. Overall, our study demonstrated the superiority of UCM-coated stimuli-responsive nanodrugs for effective and safe AS therapy.

Ultrasound Stimulation of Prefrontal Cortex Improves Lipopolysaccharide-Induced Depressive-Like Behaviors in Mice.

Increasing evidence indicates that inflammatory responses may influence brain neurochemical pathways, inducing depressive-like behaviors. Ultrasound stimulation (US) is a promising non-invasive treatment for neuropsychiatric diseases. We investigated whether US can suppress inflammation and improve depressive-like behaviors. Mice were intraperitoneally injected with lipopolysaccharide to induce depressive-like behaviors. Ultrasound wave was delivered into the prefrontal cortex (PFC) for 30 min. Depressive- and anxiety-like behaviors were evaluated through the forced swimming test (FST), tail suspension test (TST), and elevated plus maze (EPM). Biochemical analyses were performed to assess the expression of inflammatory cytokines in the PFC and serum. The results indicated that US of the PFC significantly improved depressive-like behaviors in the TST (p < 0.05) and FST (p < 0.05). Anxiety-like behaviors also improved in the EPM (p < 0.05). Furthermore, the lipopolysaccharide-mediated upregulation of IL-6, IL-1ß, and TNF-α in the PFC was significantly reduced (p < 0.05) by US. In addition, no tissue damage was observed. Overall, US of PFC can effectively improve lipopolysaccharide-induced depressive-like behaviors, possibly through the downregulation of inflammatory cytokines in the PFC. US may be a safe and promising tool for improvement of depression.

A multifunctional theranostics nanosystem featuring self-assembly of alcohol-abuse drug and photosensitizers for synergistic cancer therapy.

Conventional treatments for cancer, such as chemotherapy, surgical resection, and radiotherapy, have shown limited therapeutic efficacy, with severe side effects, lack of targeting and drug resistance for monotherapies, which limit their clinical application. Therefore, combinatorial strategies have been widely investigated in the battle against cancer. Herein, we fabricated a dual-targeted nanoscale drug delivery system based on EpCAM aptamer- and lactic acid-modified low-polyamidoamine dendrimers to co-deliver the FDA-approved agent disulfiram and photosensitizer indocyanine green, combining the imaging and therapeutic functions in a single platform. The multifunctional nanoparticles with uniform size had high drug-loading payload, sustained release, as well as excellent photothermal conversion. The integrated nanoplatform showed a superior synergistic effect in vitro and possessed precise spatial delivery to HepG2 cells with the dual-targeting nanocarrier. Intriguingly, a robust anticancer response of chemo-phototherapy was achieved; chemotherapy combined with the efficacy of phototherapy to cause cellular apoptosis of HepG2 cells (>35%) and inhibit the regrowth of damaged cells. Furthermore, the theranostic nanosystem displayed fluorescence imaging in vivo, attributed to its splendid accumulation in the tumor site, and it provided exceptional tumor inhibition rate against liver cancer cells (>76%). Overall, our research presents a promising multifunctional theranostic nanoplatform for the development of synergistic therapeutics for tumors in further applications.

Arabidopsis calcium-dependent protein kinase CPK10 functions in abscisic acid- and Ca2+-mediated stomatal regulation in response to drought stress.

Plant calcium-dependent protein kinases (CDPKs) may function as calcium sensors and play important roles in the regulation of plant growth and development and in plant responses to biotic and abiotic stresses. The Arabidopsis (Arabidopsis thaliana) genome encodes 34 CDPKs, and most of them have not been functionally characterized. Here, we report the functional characterization of CPK10 in Arabidopsis response to drought stress. The cpk10 mutant, a T-DNA insertion mutant for the Arabidopsis CPK10 gene, showed a much more sensitive phenotype to drought stress compared with wild-type plants, while the CPK10 overexpression lines displayed enhanced tolerance to drought stress. Induction of stomatal closure and inhibition of stomatal opening by abscisic acid (ABA) and Ca(2+) were impaired in the cpk10 mutants. Using yeast two-hybrid methods, a heat shock protein, HSP1, was identified as a CPK10-interacting protein. The interaction between CPK10 and HSP1 was further confirmed by pull-down and bimolecular fluorescence complementation assays. The HSP1 knockout mutant (hsp1) plants showed a similar sensitive phenotype under drought stress as the cpk10 mutant plants and were similarly less sensitive to ABA and Ca(2+) in regulation of stomatal movements. Electrophysiological experiments showed that ABA and Ca(2+) inhibition of the inward K(+) currents in stomatal guard cells were impaired in the cpk10 and hsp1 mutants. All presented data demonstrate that CPK10, possibly by interacting with HSP1, plays important roles in ABA- and Ca(2+)-mediated regulation of stomatal movements.

Association of two polymorphisms within and near SOCS3 gene with obesity in three nationalities in Xinjiang province of China.

AIM: SOCS3 gene plays an important role in the pathogenesis of obesity in animal models, but the data from human studies are relatively limited. To address this issue, a genetic association analysis on nationalities with different genetic background living in the similar environmental conditions was performed. METHODS: Two thousand seven hundred eleven subjects were randomly recruited from the Kazakh, Uygur and Han nationalities in Xinjiang of China. SNP polymorphisms rs4969168 and rs9892622 within or near the SOCS3 gene were genotyped using TaqMan-MGB™ assay. Association study between the two polymorphisms and obesity-related traits (body mass index [BMI]; waist-to-hip ratio [WHR]; weight; height, waist, and hip measurements) was conducted. RESULTS: Significant association was found between rs4969168 and the obesity-related traits, including BMI (25.32 ± 3.49 kg/m(2) for AA, 24.60 ± 3.70 kg/m(2) for AG, 24.39 ± 3.42 kg/m(2) for GG, P=0.042), weight (65.58 ± 11.42 kg for AA, 63.50 ± 11.30 kg for AG, 62.00 ± 10.78 kg for GG, P=0.011) in the Han nationality, but not in the Kazakh or Uygur nationalities. Rs9892622 was significantly associated with BMI, WHR, and WAIST in the Uygur males. Rs9892622 was also associated with BMI in Kazakh males. Linear regression analysis verified the above findings. However, neither of the two polymorphisms was associated with obesity-related traits in the total population. CONCLUSION: The polymorphism rs4969168 within or near the SOCS3 gene has a significant effect in the Han nationality, while rs9892622 was associated with obesity in Uygur and Kazakh nationalities in Xinjiang of China.

Effects of beraprost sodium, a prostaglandin I(2) analog, on high glucose-induced proliferation and oxidative stress in a rat glomerular mesangial cell line.

To investigate the effects of beraprost sodium on the proliferation and oxidative stress of glomerular mesangial cells under high glucose conditions, a rat mesangial cell line (rat mesangial cells; RMCs) was treated with beraprost sodium in the presence of high glucose concentrations. Proliferation rates of mesangial cells were detected by MTT assays and BrdU incorporation analyses. Levels of reactive oxygen species (ROS) were detected by DCFH-DA probes. The mRNA expression levels of CuZnSOD, MnSOD, catalase (CAT), glutathione peroxidase (Gpx), and collagen IV were detected by RT-PCR, and the protein levels of antioxidants (i.e. CuZnSOD, CAT, and MnSOD) and collagen IV were detected by Western blot. Beraprost sodium treatment significantly decreased the proliferation and ROS levels of RMCs cultured in high glucose conditions in a dose-dependent manner (p < 0.05). Beraprost sodium treatment decreased the mRNA and protein levels of CuZnSOD, CAT, and collagen IV in cells under high glucose conditions, while it increased MnSOD protein levels in cells under normal glucose conditions. Therefore, beraprost sodium inhibits high glucose-induced cellular proliferation and the generation of ROS, and it improves the antioxidant capacities of rat glomerular mesangial cells.

Accelerating transdermal delivery of insulin by ginsenoside nanoparticles with unique permeability.

Diabetes is a metabolic disease caused by insufficient insulin secretion, action or resistance, in which insulin plays an irreplaceable role in the its treatment. However, traditional administration of insulin requires continuous subcutaneous injections, which is accompanied by inevitable pain, local tissue necrosis and hypoglycemia. Herein, a green and safe nanoformulation with unique permeability composed of insulin and ginsenosides is developed for transdermal delivery to reduce above-mentioned side effects. The ginsenosides are self-assembled to form shells to protect insulin from hydrolysis and improve the stability of nanoparticles. The nanoparticles can temporarily permeate into cells in 5 min and promptly excrete from the cell for deeper penetration. The insulin permeation is related to the disorder of stratum corneum lipids caused by ginsenosides. The skin acting as drug depot mantains the nanoparticles released continuously, therefore the body keeps euglycemic for 48 h. Encouraged by its long-lasting and effective transdermal therapy, ginsenosides-based nano-system is expected to deliver other less permeable drugs like proteins and peptides and benefit those who are with chronic diseases that need long-term medication.

Mechanistic study of endogenous skin lesions in diabetic rats.

Pathological and physiological changes in dermal tissue in a rat model of diabetes mellitus (DM) were investigated. Sixteen male 8-week-old Sprague-Dawley rats were randomized into two groups of eight, the DM group (Group DM) and the normal control group (Group (NC) normal control). Group DM rats were injected with streptozotocin (STZ) intraperitoneally at a dose of 65 mg/kg body weight. Group NC rats were injected with the same volume of citric acid buffer. All rats were sacrificed 12 weeks later. The impact of exposure to (AGE) advanced glycation end products-modified human serum albumin (AGE-HSA) on epidermal cells and ECV304 cells was evaluated in cell culture experiments. The diabetic rats exhibited changes in skin tissue, including a decrease in thickness, disappearance of the multilayer epithelium structure, degeneration of collagen fibres and an increase in the infiltration of inflammatory cells, in addition to a significant increase in skin glucose and AGEs. Moreover, diabetic rats had increased plasma glycosylated protein (GSP) and malondialdehyde (MDA) and decreased plasma glutathione (GSH). The percentage of epidermal cells in S phase was similar between the two group rats; however, there was a marked decrease in the G2/M phase in Group DM. Additionally, exposure of ECV304 cells to AGE-HSA led to a time-dependent and dose-dependent increase in apoptosis. Therefore, the high glucose in the skin tissue, coupled with the accumulation of toxic substances such as AGEs, promote the dysfunction of dermal cells and/or the matrix. This may be a significant mechanism of diabetes-induced early-stage endogenous skin damage.

Co-delivery of Sorafenib and CRISPR/Cas9 Based on Targeted Core-Shell Hollow Mesoporous Organosilica Nanoparticles for Synergistic HCC Therapy.

The rapid development of CRISPR/Cas9 systems has opened up tantalizing prospects to sensitize cancers to chemotherapy using efficient targeted genome editing, but safety concerns and possible off-target effects of viral vectors remain a major obstacle for clinical application. Thus, the construction of novel nonviral tumor-targeting nanodelivery systems has great potential for the safe application of CRISPR/Cas9 systems for gene-chemo-combination therapy. Here, we report a polyamidoamine-aptamer-coated hollow mesoporous silica nanoparticle for the co-delivery of sorafenib and CRISPR/Cas9. The core-shell nanoparticles had good stability, enabled ultrahigh drug loading, targeted delivery, and controlled-release of the gene-drug combination. The nanocomplex showed >60% EGFR-editing efficiency without off-target effects in all nine similar sites, regulating the EGFR-PI3K-Akt pathway to inhibit angiogenesis, and exhibited a synergistic effect on cell proliferation. Importantly, the co-delivery nanosystem achieved efficient EGFR gene therapy and caused 85% tumor inhibition in a mouse model. Furthermore, the nanocomplex showed high accumulation at the tumor site in vivo and exhibited good safety with no damage to major organs. Due to these properties, the nanocomplex provides a versatile delivery approach for efficient co-loading of gene-drug combinations, allowing for precise gene editing and synergistic inhibition of tumor growth without apparent side effects on normal tissues.

High glucose stimulates cell proliferation and Collagen IV production in rat mesangial cells through inhibiting AMPK-KATP signaling.

PURPOSE: The present study investigated the putative mechanisms underlying effects of KATP channel on high glucose (HG)-induced mesangial cell proliferation and tissue inhibitors of metalloproteinases (TIMP)-2 and Collagen IV production. METHODS: Rat mesangial cells were subjected to whole cell patch clamp to record the KATP channel currents under high glucose (HG, 30 mM) condition. Cell proliferation was measured using a CCK-8 assay. The production of TIMP-2 and Collagen IV and AMP-activated protein kinase (AMPK)-signaling pathway activity was assessed by ELISA and Western blotting, respectively. AMPK agonist (AICAR) was used to analyze the role of this kinase. The expression of KATP subunit (Kir6.1, Kir6.2, SUR1, SUR2A and SUR2B) was examined using quantitative real-time PCR (RT-PCR). RESULTS: We found that HG was significant decreases in the expression of Kir6.1, SUB2A and SUB2B, three subunits of KATP, TIMP-2 production, KATP channel activity and AMPK activity, while it promoted the cell proliferation and Collagen IV production in rat mesangial cells. Pretreatment with KATP selective opener (diazoxide, DZX) significantly inhibited HG-induced mesangial cell proliferation, Collagen IV production and decrease in KATP channel activity in rat mesangial cells, which were reversed by pretreatment of 5-hydroxydecanoate, a selective inhibitor of KATP. Moreover, AICAR pretreatment inhibited HG-induced decrease in KATP channel activity. CONCLUSIONS: Taken together, activating AMPK-KATP signaling may protect against HG-induced mesangial cell proliferation and Collagen IV production, and, thereby, provides new insights into the molecular mechanisms underlying early diabetic nephropathy (DN).

Receptor for advanced glycation end as drug targets in diabetes-induced skin lesion.

The involvement of the receptor for advanced glycation end (RAGE) in different diseases has been reviewed in great detail, previously, but the effects of diabetic drugs on RAGE-induced skin lesion during long course diabetes remains poorly understood. In the present study, we have shown that RAGE was overexpressed in both diabetic rats and human keratinocytes (HaCaT cells). Cell cycle arrest and apoptosis as well as alternations of relative protein levels were also found in diabetic rats and HaCaT cells with overexpression of RAGE that were rectified by metformin (Met) treatment. Moreover, overexpression of RAGE was also found to induce secretions of TNF-α, IL-1ß, IL-6, ICAM-1 and COX-2 in HaCaT cells, and Met treatment corrected these inflammatory factor secretions. In addition, treatment with Met markedly reduced RAGE overexpression-induced p38 and NF-κB activation. Taken together, the findings of the present study have demonstrated, for the first time that Met protects HaCaT cells against diabetes-induced injuries and inflammatory responses through inhibiting activated RAGE.

Transplantation of betatrophin-expressing adipose-derived mesenchymal stem cells induces ß-cell proliferation in diabetic mice.

Recent progress in regenerative medicine has suggested that mesenchymal stem cell (MSC)-based therapy is a novel potential cure for diabetes. Betatrophin is a newly identified hormone that can increase the production and expansion of insulin-secreting ß-cells when administered to mice. In this study, we evaluated the effect of betatrophin overexpression by human adipose-derived MSCs (ADMSCs) by in vitro experiments, as well as following their transplantation into a mice with streptozotocin (STZ)-induced diabetes. The overexpression of betatrophin did not affect the ADMSCs in terms of proliferation, differentiation and morphology. However, the co-culture of human islets with ADMSCs overexpressing betatrophin (ADMSCs-BET) induced islet proliferation, ß-cell specific transcription factor expression, and the islet production of insulin under the stimulation of glucose or KCl and Arg. In addition, ADMSCs-BET enhanced the anti-inflammatory and anti-apoptotic effects of the co-cultured islets compared with ADMSCs cultured alone. In mice with STZ-induced diabetes, the transplantation of ADMSCs-BET ameliorated the hyperglycemia and weight loss associated with STZ-induced diabetes; ADMSCs-BET also significantly enhanced the ratio of ß-cells per islet compared to the transplantation of ADMSCs alone. Thus, our study demonstrates a novel strategy for inducing ß-cell regeneration. ADMSCs-BET may replace insulin injections by increasing the number of endogenous insulin-producing cells in patients with diabetes. This combined strategy of ADMSC transplantation and gene therapy may prove to be a useful therapy for the treatment of diabetes.