Bidirectional modulation of TCA cycle metabolites and anaplerosis by metformin and its combination with SGLT2i.

BACKGROUND: Metformin and sodium-glucose-cotransporter-2 inhibitors (SGLT2i) are cornerstone therapies for managing hyperglycemia in diabetes. However, their detailed impacts on metabolic processes, particularly within the citric acid (TCA) cycle and its anaplerotic pathways, remain unclear. This study investigates the tissue-specific metabolic effects of metformin, both as a monotherapy and in combination with SGLT2i, on the TCA cycle and associated anaplerotic reactions in both mice and humans. METHODS: Metformin-specific metabolic changes were initially identified by comparing metformin-treated diabetic mice (MET) with vehicle-treated db/db mice (VG). These findings were then assessed in two human cohorts (KORA and QBB) and a longitudinal KORA study of metformin-naïve patients with Type 2 Diabetes (T2D). We also compared MET with db/db mice on combination therapy (SGLT2i + MET). Metabolic profiling analyzed 716 metabolites from plasma, liver, and kidney tissues post-treatment, using linear regression and Bonferroni correction for statistical analysis, complemented by pathway analyses to explore the pathophysiological implications. RESULTS: Metformin monotherapy significantly upregulated TCA cycle intermediates such as malate, fumarate, and α-ketoglutarate (α-KG) in plasma, and anaplerotic substrates including hepatic glutamate and renal 2-hydroxyglutarate (2-HG) in diabetic mice. Downregulated hepatic taurine was also observed. The addition of SGLT2i, however, reversed these effects, such as downregulating circulating malate and α-KG, and hepatic glutamate and renal 2-HG, but upregulated hepatic taurine. In human T2D patients on metformin therapy, significant systemic alterations in metabolites were observed, including increased malate but decreased citrulline. The bidirectional modulation of TCA cycle intermediates in mice influenced key anaplerotic pathways linked to glutaminolysis, tumorigenesis, immune regulation, and antioxidative responses. CONCLUSION: This study elucidates the specific metabolic consequences of metformin and SGLT2i on the TCA cycle, reflecting potential impacts on the immune system. Metformin shows promise for its anti-inflammatory properties, while the addition of SGLT2i may provide liver protection in conditions like metabolic dysfunction-associated steatotic liver disease (MASLD). These observations underscore the importance of personalized treatment strategies.

Gemtuzumab ozogamicin plus midostaurin in combination with standard '7 + 3' induction therapy in newly diagnosed AML: Results from the SAL-MODULE phase I study.

We conducted a phase I trial in newly diagnosed acute myeloid leukaemia (AML) to investigate the combination of two novel targeted agents, gemtuzumab ozogamicin (GO) and midostaurin, with intensive chemotherapy in FLT3-mutated AML and CBF leukaemia. Three dose levels of midostaurin and one to three sequential doses of 3 mg/m2 GO in combination with '7 + 3' induction were evaluated. Based on safety findings in 12 patients, our results show that 3 mg/m2 GO on Days 1 + 4 and 100 mg midostaurin on Days 8-21 can be safely combined with IC in newly diagnosed AML.

Time from diagnosis to treatment has no impact on survival in newly diagnosed acute myeloid leukemia treated with venetoclax-based regimens.

In newly diagnosed acute myeloid leukemia, immediate initiation of treatment is standard of care. However, deferral of antileukemic therapy may be indicated to assess comorbidities or pre-therapeutic risk factors. We explored the impact of time from diagnosis to treatment on outcomes in newly diagnosed acute myeloid leukemia undergoing venetoclax-based therapy in two distinct cohorts. By querying the Study Alliance Leukemia database and the global health network TriNetX, we identified 138 and 717 patients respectively with an average age of 76 and 72 years who received venetoclax-based firstline therapy. When comparing patients who started treatment earlier or later than 10 days after initial diagnosis, no significant difference in median overall survival was observed - neither in the SAL cohort (7.7 vs. 9.6 months, p=.42) nor in the TriNetX cohort (7.5 vs. 7.2 months, p=.41). Similarly, severe infections, bleeding, and thromboembolic events were equally observed between early and later treatments, both in the overall patient groups and specific subgroups (age ≥75 years or leukocytes ≥20x109/L). This retrospective analysis indicates that delaying the start of venetoclax-based therapy in newly diagnosed acute myeloid leukemia might be a safe option for selected patients, provided that close clinical monitoring is performed.

Role of the soluble epoxide hydrolase in keratinocyte proliferation and sensitivity of skin to inflammatory stimuli.

The lipid content of skin plays a determinant role in its barrier function with a particularly important role attributed to linoleic acid and its derivatives. Here we explored the consequences of interfering with the soluble epoxide hydrolase (sEH) on skin homeostasis. sEH; which converts fatty acid epoxides generated by cytochrome P450 enzymes to their corresponding diols, was largely restricted to the epidermis which was enriched in sEH-generated diols. Global deletion of the sEH increased levels of epoxides, including the linoleic acid-derived epoxide; 12,13-epoxyoctadecenoic acid (12,13-EpOME), and increased basal keratinocyte proliferation. sEH deletion (sEH-/- mice) resulted in thicker differentiated spinous and corneocyte layers compared to wild-type mice, a hyperkeratosis phenotype that was reproduced in wild-type mice treated with a sEH inhibitor. sEH deletion made the skin sensitive to inflammation and sEH-/- mice developed thicker imiquimod-induced psoriasis plaques than the control group and were more prone to inflammation triggered by mechanical stress with pronounced infiltration and activation of neutrophils as well as vascular leak and increased 12,13-EpOME and leukotriene (LT) B4 levels. Topical treatment of LTB4 antagonist after stripping successfully inhibited inflammation and neutrophil infiltration both in wild type and sEH-/- skin. While 12,13-EpoME had no effect on the trans-endothelial migration of neutrophils, like LTB4, it effectively induced neutrophil adhesion and activation. These observations indicate that while the increased accumulation of neutrophils in sEH-deficient skin could be attributed to the increase in LTB4 levels, both 12,13-EpOME and LTB4 contribute to neutrophil activation. Our observations identify a protective role of the sEH in the skin and should be taken into account when designing future clinical trials with sEH inhibitors.

Disrupted Binding of Cystathionine γ-Lyase to p53 Promotes Endothelial Senescence.

BACKGROUND: Advanced age is unequivocally linked to the development of cardiovascular disease; however, the mechanisms resulting in reduced endothelial cell regeneration remain poorly understood. Here, we investigated novel mechanisms involved in endothelial cell senescence that impact endothelial cell transcription and vascular repair after injury. METHODS: Native endothelial cells were isolated from young (20±3.4 years) and aged (80±2.3 years) individuals and subjected to molecular analyses to assess global transcriptional and metabolic changes. In vitro studies were conducted using primary human and murine endothelial cells. A murine aortic re-endothelialization model was used to examine endothelial cell regenerative capacity in vivo. RESULTS: RNA sequencing of native endothelial cells revealed that aging resulted in p53-mediated reprogramming to express senescence-associated genes and suppress glycolysis. Reduced glucose uptake and ATP contributed to attenuated assembly of the telomerase complex, which was required for endothelial cell proliferation. Enhanced p53 activity in aging was linked to its acetylation on K120 due to enhanced activity of the acetyltransferase MOZ (monocytic leukemic zinc finger). Mechanistically, p53 acetylation and translocation were, at least partially, attributed to the loss of the vasoprotective enzyme, CSE (cystathionine γ-lyase). CSE physically anchored p53 in the cytosol to prevent its nuclear translocation and CSE absence inhibited AKT (Protein kinase B)-mediated MOZ phosphorylation, which in turn increased MOZ activity and subsequently p53 acetylation. In mice, the endothelial cell-specific deletion of CSE activated p53, induced premature endothelial senescence, and arrested vascular repair after injury. In contrast, the adeno-associated virus 9-mediated re-expression of an active CSE mutant retained p53 in the cytosol, maintained endothelial glucose metabolism and proliferation, and prevented endothelial cell senescence. Adenoviral overexpression of CSE in native endothelial cells from aged individuals maintained low p53 activity and reactivated telomerase to revert endothelial cell senescence. CONCLUSIONS: Aging-associated impairment of vascular repair is partly determined by the vasoprotective enzyme CSE.

Inhibition of fatty acid oxidation enables heart regeneration in adult mice.

Postnatal maturation of cardiomyocytes is characterized by a metabolic switch from glycolysis to fatty acid oxidation, chromatin reconfiguration and exit from the cell cycle, instating a barrier for adult heart regeneration1,2. Here, to explore whether metabolic reprogramming can overcome this barrier and enable heart regeneration, we abrogate fatty acid oxidation in cardiomyocytes by inactivation of Cpt1b. We find that disablement of fatty acid oxidation in cardiomyocytes improves resistance to hypoxia and stimulates cardiomyocyte proliferation, allowing heart regeneration after ischaemia-reperfusion injury. Metabolic studies reveal profound changes in energy metabolism and accumulation of α-ketoglutarate in Cpt1b-mutant cardiomyocytes, leading to activation of the α-ketoglutarate-dependent lysine demethylase KDM5 (ref. 3). Activated KDM5 demethylates broad H3K4me3 domains in genes that drive cardiomyocyte maturation, lowering their transcription levels and shifting cardiomyocytes into a less mature state, thereby promoting proliferation. We conclude that metabolic maturation shapes the epigenetic landscape of cardiomyocytes, creating a roadblock for further cell divisions. Reversal of this process allows repair of damaged hearts.

ADPGK-AS1 long noncoding RNA switches macrophage metabolic and phenotypic state to promote lung cancer growth.

Long noncoding RNAs (lncRNAs) influence the transcription of gene networks in many cell types, but their role in tumor-associated macrophages (TAMs) is still largely unknown. We found that the lncRNA ADPGK-AS1 was substantially upregulated in artificially induced M2-like human macrophages, macrophages exposed to lung cancer cells in vitro, and TAMs from human lung cancer tissue. ADPGK-AS1 is partly located within mitochondria and binds to the mitochondrial ribosomal protein MRPL35. Overexpression of ADPGK-AS1 in macrophages upregulates the tricarboxylic acid cycle and promotes mitochondrial fission, suggesting a phenotypic switch toward an M2-like, tumor-promoting cytokine release profile. Macrophage-specific knockdown of ADPGK-AS1 induces a metabolic and phenotypic switch (as judged by cytokine profile and production of reactive oxygen species) to a pro-inflammatory tumor-suppressive M1-like state, inhibiting lung tumor growth in vitro in tumor cell-macrophage cocultures, ex vivo in human tumor precision-cut lung slices, and in vivo in mice. Silencing ADPGK-AS1 in TAMs may thus offer a novel therapeutic strategy for lung cancer.

A transient increase of HIF-1α during the G1 phase (G1-HIF) ensures cell survival under nutritional stress.

The family of hypoxia-inducible transcription factors (HIF) is activated to adapt cells to low oxygen conditions, but is also known to regulate some biological processes under normoxic conditions. Here we show that HIF-1α protein levels transiently increase during the G1 phase of the cell cycle (designated as G1-HIF) in an AMP-activated protein kinase (AMPK)-dependent manner. The transient elimination of G1-HIF by a degron system revealed its contribution to cell survival under unfavorable metabolic conditions. Indeed, G1-HIF plays a key role in the cell cycle-dependent expression of genes encoding metabolic regulators and the maintenance of mTOR activity under conditions of nutrient deprivation. Accordingly, transient elimination of G1-HIF led to a significant reduction in the concentration of key proteinogenic amino acids and carbohydrates. These data indicate that G1-HIF acts as a cell cycle-dependent surveillance factor that prevents the onset of starvation-induced apoptosis.

UBTF tandem duplications are rare but recurrent alterations in adult AML and associated with younger age, myelodysplasia, and inferior outcome.

Tandem-duplication mutations of the UBTF gene (UBTF-TDs) coding for the upstream binding transcription factor have recently been described in pediatric patients with acute myeloid leukemia (AML) and were found to be associated with particular genetics (trisomy 8 (+8), FLT3-internal tandem duplications (FLT3-ITD), WT1-mutations) and inferior outcome. Due to limited knowledge on UBTF-TDs in adult AML, we screened 4247 newly diagnosed adult AML and higher-risk myelodysplastic syndrome (MDS) patients using high-resolution fragment analysis. UBTF-TDs were overall rare (n = 52/4247; 1.2%), but significantly enriched in younger patients (median age 41 years) and associated with MDS-related morphology as well as significantly lower hemoglobin and platelet levels. Patients with UBTF-TDs had significantly higher rates of +8 (34% vs. 9%), WT1 (52% vs. 7%) and FLT3-ITD (50% vs. 20.8%) co-mutations, whereas UBTF-TDs were mutually exclusive with several class-defining lesions such as mutant NPM1, in-frame CEBPAbZIP mutations as well as t(8;21). Based on the high-variant allele frequency found and the fact that all relapsed patients analyzed (n = 5) retained the UBTF-TD mutation, UBTF-TDs represent early clonal events and are stable over the disease course. In univariate analysis, UBTF-TDs did not represent a significant factor for overall or relapse-free survival in the entire cohort. However, in patients under 50 years of age, who represent the majority of UBTF-mutant patients, UBTF-TDs were an independent prognostic factor for inferior event-free (EFS), relapse-free (RFS) and overall survival (OS), which was confirmed by multivariable analyses including established risk factors such as age and ELN2022 genetic risk groups (EFS [HR: 2.20; 95% CI 1.52-3.17, p < 0.001], RFS [HR: 1.59; 95% CI 1.02-2.46, p = 0.039] and OS [HR: 1.64; 95% CI 1.08-2.49, p = 0.020]). In summary, UBTF-TDs appear to represent a novel class-defining lesion not only in pediatric AML but also younger adults and are associated with myelodysplasia and inferior outcome in these patients.

Impact of trisomy 19 on outcome according to genetic makeup in patients with acute myeloid leukemia.

We retrospectively studied 97 acute myeloid leukemia patients with trisomy 19 (median age at diagnosis 57 years; range, 17- 83 years) treated between 2001 and 2019 within two multicenter study groups. Trisomy 19 occurred alone in ten (10.5%) patients, with additional abnormalities being present in non-complex karyotypes in eight (8%) patients and in complex karyotypes in 79 (82%) patients. Altogether, karyotypes characterized by trisomies only were present in 27 (28%) patients. Data on response and outcome of intensively treated patients were available for 92 cases. The median follow-up was 6.4 years (95% confidence interval [95% CI]: 2.9-9.0 years). The complete remission (CR) rate after induction therapy was 52% (48 patients); the early death rate was 10% (n=9). Notably, patients with trisomy 19 as the sole abnormality had a CR rate of 89%. Allogeneic hematopoietic stem cell transplantation (allo-HCT) was performed in 34 (35%) patients (CR, n=19; active disease, n=15). Five-year relapse-free and overall survival rates were 26% (95% CI: 16-43%) and 20% (95% CI: 13-31%), respectively. Overall survival rates were significantly higher in patients with trisomy 19 as the sole abnormality or within karyotypes characterized by trisomies only (P=0.05). An Andersen-Gill model including allo-HCT as a time-dependent covariable on overall survival revealed that trisomy 19 as the sole abnormality or within karyotypes characterized by trisomies only was a favorable factor (hazard ratio [HR]=0.47; P=0.021); higher age at diagnosis had an adverse impact (10 years difference; HR=1.29; P=0.002), whereas allo-HCT did not have a beneficial impact (odds ratio=1.45; P=0.21). In our cohort, patients with trisomy 19 as the sole abnormality or within karyotypes characterized by trisomies only had a high CR rate and better clinical outcome.

Characteristics and outcome of patients with acute myeloid leukemia and trisomy 4.

We retrospectively studied 125 patients with acute myeloid leukemia and trisomy 4 (median age at diagnosis, 58 years; range, 16-77 years) treated between 2000 and 2019 within a multicenter study. Trisomy 4 was the sole abnormality in 28 (22%) patients and additional abnormalities were present in 97 (78%) patients. Twenty-two (22%) and 15 (15%) of 101 tested patients harbored NPM1 and FLT3-ITD mutations. Two (3%) of 72 tested patients had double CEBPA mutations. Data on response to intensive anthracycline-based induction therapy were available for 119 patients. Complete remission was achieved in 67% (n=80) and the early death rate was 5% (n=6). Notably, patients with trisomy 4 as sole abnormality had a complete remission rate of 89%. Allogeneic hematopoietic cell transplantation was performed in 40 (34%) patients, of whom 19 were transplanted in first complete remission. The median follow-up of the intensively treated cohort was 5.76 years (95% confidence interval [95% CI]: 2.99-7.61 years). The 5-year overall survival and relapse-free survival rates were 30% (95% CI: 22-41%) and 27% (95% CI: 18-41%), respectively. An Andersen-Gill regression model on overall survival revealed that favorable-risk according to the European LeukemiaNet classification (hazard ratio [HR]=0.34; P=0.006) and trisomy 4 as sole abnormality (HR=0.41; P=0.01) were favorable factors, whereas age with a difference of 10 years (HR=1.15; P=0.11), female gender (HR=0.74; P=0.20) and allogeneic hematopoietic cell transplantation (HR=0.64; P=0.14) did not have an significant impact. In our cohort, patients with trisomy 4 as their sole abnormality had a high complete remission rate and favorable clinical outcome. Allogeneic hematopoietic cell transplantation did not seem to improve overall survival.

Sustained Endurance Training Leads to Metabolomic Adaptation.

Endurance training induces several adaptations in substrate metabolism, especially in relation to glycogen conservation. The study aimed to investigate differences in the metabolism of lipids, lipid-like substances, and amino acids between highly trained and untrained subjects using targeted metabolomics. Depending on their maximum relative oxygen uptake (VO2max), subjects were categorized as either endurance-trained (ET) or untrained (UT). Resting blood was taken and plasma isolated. It was screened for changes of 345 metabolites, including amino acids and biogenic amines, acylcarnitines, glycerophosphocholines (GPCs), sphingolipids, hexoses, bile acids, and polyunsaturated fatty acids (PUFAs) by using liquid chromatography coupled to tandem mass spectrometry. Acylcarnitine (C14:1, down in ET) and five GPCs (lysoPC a C18:2, up in ET; PC aa C42:0, up in ET; PC ae C38:2, up in ET; PC aa C38:5, down in ET; lysoPC a C26:0, down in ET) were differently regulated in ET compared to UT. TCDCA was down-regulated in athletes, while for three ratios of bile acids CA/CDCA, CA/(GCA+TCA), and DCA/(GDCA+TDCA) an up-regulation was found. TXB2 and 5,6-EET were down-regulated in the ET group and 18S-HEPE, a PUFA, showed higher levels in 18S-HEPE in endurance-trained subjects. For PC ae C38:2, TCDCA, and the ratio of cholic acid to chenodeoxycholic acid, an association with VO2max was found. Numerous phospholipids, acylcarnitines, glycerophosphocholines, bile acids, and PUFAs are present in varying concentrations at rest in ET. These results might represent an adaptation of lipid metabolism and account for the lowered cardiovascular risk profile of endurance athletes.

Role of the soluble epoxide hydrolase in the hair follicle stem cell homeostasis and hair growth.

Polyunsaturated fatty acids (PUFAs) are used as traditional remedies to treat hair loss, but the mechanisms underlying their beneficial effects are not well understood. Here, we explored the role of PUFA metabolites generated by the cytochrome P450/soluble epoxide hydrolase (sEH) pathway in the regulation of the hair follicle cycle. Histological analysis of the skin from wild-type and sEH-/- mice revealed that sEH deletion delayed telogen to anagen transition, and the associated activation of hair follicle stem cells. Interestingly, EdU labeling during the late anagen stage revealed that hair matrix cells from sEH-/- mice proliferated at a greater rate which translated into increased hair growth. Similar effects were observed in in vitro studies using hair follicle explants, where a sEH inhibitor was also able to augment whisker growth in follicles from wild-type mice. sEH activity in the dorsal skin was not constant but altered with the cell cycle, having the most prominent effects on levels of the linoleic acid derivatives 12,13-epoxyoctadecenoic acid (12,13-EpOME), and 12,13-dihydroxyoctadecenoic acid (12,13-DiHOME). Fitting with this, the sEH substrate 12,13-EpOME significantly increased hair shaft growth in isolated anagen stage hair follicles, while its diol; 12,13-DiHOME, had no effect. RNA sequencing of isolated hair matrix cells implicated altered Wnt signaling in the changes associated with sEH deletion. Taken together, our data indicate that the activity of the sEH in hair follicle changes during the hair follicle cycle and impacts on two stem cell populations, i.e., hair follicle stem cells and matrix cells to affect telogen to anagen transition and hair growth.

Point Mutations in the FLT3-ITD Region Are Rare but Recurrent Alterations in Adult AML and Associated With Concomitant KMT2A-PTD.

FLT3-ITD mutations are common druggable alterations in patients with acute myeloid leukemia (AML) and associated with poor prognosis. Beside typical ITD mutations, point mutations and deletions in the juxtamembrane domain (JMD) have been observed. However, due to the low frequency of these alterations, there is only limited information on molecular and clinical associations. To evaluate the prognostic impact of non-ITD mutations in the FLT3 JMD region, we analyzed a large cohort of 1,539 adult AML patients treated in different protocols of the Study Alliance Leukemia, using next-generation sequencing. Non-ITD point mutations and deletions within the FLT3 JMD were identified with a prevalence of ~1.23% (n = 19). Both FLT3-ITD and non-ITD mutations were associated with a higher rate of NPM1 (42%-61%; p < 0.001) and DNMT3A mutations (37%-43%; p < 0.001), as well as an increased percentage of peripheral blood (54%-65%) and bone marrow blast cells (74%; p < 0.001), compared to FLT3-wild-type patients. Most significantly, AML patients with FLT3 non-ITD mutations had a higher rate of concomitant KMT2A-PTD mutations (37.5%; p < 0.001) as compared to FLT3-ITD (7%) or FLT3-wild-type cases (4.5%). In a multivariable analysis, FLT3 non-ITD mutations were not an independent prognostic factor. However, patients with dual FLT3 non-ITD and KMT2A-PTD mutations showed a trend for inferior outcome, which points at a functional interaction in this subset of AML.

Phosphatidylserine Synthase PTDSS1 Shapes the Tumor Lipidome to Maintain Tumor-Promoting Inflammation.

An altered lipidome in tumors may affect not only tumor cells themselves but also their microenvironment. In this study, a lipidomics screen reveals increased amounts of phosphatidylserine (PS), particularly ether-PS (ePS), in murine mammary tumors compared with normal tissue. PS was produced by phosphatidylserine synthase 1 (PTDSS1), and depletion of Ptdss1 from tumor cells in mice reduced ePS levels accompanied by stunted tumor growth and decreased tumor-associated macrophage (TAM) abundance. Ptdss1-deficient tumor cells exposed less PS during apoptosis, which was recognized by the PS receptor MERTK. Mammary tumors in macrophage-specific Mertk-/- mice showed similarly suppressed growth and reduced TAM infiltration. Transcriptomic profiles of TAMs from Ptdss1-knockdown tumors and Mertk-/- TAMs revealed that macrophage proliferation was reduced when the Ptdss1/Mertk pathway was targeted. Moreover, PTDSS1 expression correlated positively with TAM abundance but negatively with breast carcinoma patient survival. PTDSS1 thus may be a target to modify tumor-promoting inflammation. SIGNIFICANCE: This study shows that inhibiting the production of ether-phosphatidylserine by targeting phosphatidylserine synthase PTDSS1 limits tumor-associated macrophage expansion and breast tumor growth.

G-protein-coupled receptor P2Y10 facilitates chemokine-induced CD4 T cell migration through autocrine/paracrine mediators.

G-protein-coupled receptors (GPCRs), especially chemokine receptors, play a central role in the regulation of T cell migration. Various GPCRs are upregulated in activated CD4 T cells, including P2Y10, a putative lysophospholipid receptor that is officially still considered an orphan GPCR, i.e., a receptor with unknown endogenous ligand. Here we show that in mice lacking P2Y10 in the CD4 T cell compartment, the severity of experimental autoimmune encephalomyelitis and cutaneous contact hypersensitivity is reduced. P2Y10-deficient CD4 T cells show normal activation, proliferation and differentiation, but reduced chemokine-induced migration, polarization, and RhoA activation upon in vitro stimulation. Mechanistically, CD4 T cells release the putative P2Y10 ligands lysophosphatidylserine and ATP upon chemokine exposure, and these mediators induce P2Y10-dependent RhoA activation in an autocrine/paracrine fashion. ATP degradation impairs RhoA activation and migration in control CD4 T cells, but not in P2Y10-deficient CD4 T cells. Importantly, the P2Y10 pathway appears to be conserved in human T cells. Taken together, P2Y10 mediates RhoA activation in CD4 T cells in response to auto-/paracrine-acting mediators such as LysoPS and ATP, thereby facilitating chemokine-induced migration and, consecutively, T cell-mediated diseases.

Repression of Osmr and Fgfr1 by miR-1/133a prevents cardiomyocyte dedifferentiation and cell cycle entry in the adult heart.

Dedifferentiation of cardiomyocytes is part of the survival program in the remodeling myocardium and may be essential for enabling cardiomyocyte proliferation. In addition to transcriptional processes, non-coding RNAs play important functions for the control of cell cycle regulation in cardiomyocytes and cardiac regeneration. Here, we demonstrate that suppression of FGFR1 and OSMR by miR-1/133a is instrumental to prevent cardiomyocyte dedifferentiation and cell cycle entry in the adult heart. Concomitant inactivation of both miR-1/133a clusters in adult cardiomyocytes activates expression of cell cycle regulators, induces a switch from fatty acid to glycolytic metabolism, and changes expression of extracellular matrix genes. Inhibition of FGFR and OSMR pathways prevents most effects of miR-1/133a inactivation. Short-term miR-1/133a depletion protects cardiomyocytes against ischemia, while extended loss of miR-1/133a causes heart failure. Our results demonstrate a crucial role of miR-1/133a­mediated suppression of Osmr and Ffgfr1 in maintaining the postmitotic differentiated state of cardiomyocytes.

The Consequences of Soluble Epoxide Hydrolase Deletion on Tumorigenesis and Metastasis in a Mouse Model of Breast Cancer.

Epoxides and diols of polyunsaturated fatty acids (PUFAs) are bioactive and can influence processes such as tumor cell proliferation and angiogenesis. Studies with inhibitors of the soluble epoxide hydrolase (sEH) in animals overexpressing cytochrome P450 enzymes or following the systemic administration of specific epoxides revealed a markedly increased incidence of tumor metastases. To determine whether PUFA epoxides increased metastases in a model of spontaneous breast cancer, sEH-/- mice were crossed onto the polyoma middle T oncogene (PyMT) background. We found that the deletion of the sEH accelerated the growth of primary tumors and increased both the tumor macrophage count and angiogenesis. There were small differences in the epoxide/diol content of tumors, particularly in epoxyoctadecamonoenic acid versus dihydroxyoctadecenoic acid, and marked changes in the expression of proteins linked with cell proliferation and metabolism. However, there was no consequence of sEH inhibition on the formation of metastases in the lymph node or lung. Taken together, our results confirm previous reports of increased tumor growth in animals lacking sEH but fail to substantiate reports of enhanced lymph node or pulmonary metastases.

Validation of Candidate Phospholipid Biomarkers of Chronic Kidney Disease in Hyperglycemic Individuals and Their Organ-Specific Exploration in Leptin Receptor-Deficient db/db Mouse.

Biological exploration of early biomarkers for chronic kidney disease (CKD) in (pre)diabetic individuals is crucial for personalized management of diabetes. Here, we evaluated two candidate biomarkers of incident CKD (sphingomyelin (SM) C18:1 and phosphatidylcholine diacyl (PC aa) C38:0) concerning kidney function in hyperglycemic participants of the Cooperative Health Research in the Region of Augsburg (KORA) cohort, and in two biofluids and six organs of leptin receptor-deficient (db/db) mice and wild type controls. Higher serum concentrations of SM C18:1 and PC aa C38:0 in hyperglycemic individuals were found to be associated with lower estimated glomerular filtration rate (eGFR) and higher odds of CKD. In db/db mice, both metabolites had a significantly lower concentration in urine and adipose tissue, but higher in the lungs. Additionally, db/db mice had significantly higher SM C18:1 levels in plasma and liver, and PC aa C38:0 in adrenal glands. This cross-sectional human study confirms that SM C18:1 and PC aa C38:0 associate with kidney dysfunction in pre(diabetic) individuals, and the animal study suggests a potential implication of liver, lungs, adrenal glands, and visceral fat in their systemic regulation. Our results support further validation of the two phospholipids as early biomarkers of renal disease in patients with (pre)diabetes.