MicroRNA Regulatory Pattern in Diabetic Mouse Cortex at Different Stages Following Ischemic Stroke.

After ischemic stroke, microRNAs (miRNAs) participate in various processes, including immune responses, inflammation, and angiogenesis. Diabetes is a key factor increasing the risk of ischemic stroke; however, the regulatory pattern of miRNAs at different stages of diabetic stroke remains unclear. This study comprehensively analyzed the miRNA expression profiles in diabetic mice at 1, 3, and 7 days post-reperfusion following the middle cerebral artery occlusion (MCAO). We identified differentially expressed (DE) miRNAs in diabetic stroke and found significant dysregulation of some novel miRNAs (novel_mir310, novel_mir89, and novel_mir396) post-stroke. These DEmiRNAs were involved in apoptosis and the formation of tight junctions. Finally, we identified three groups of time-dependent DE miRNAs (miR-6240, miR-135b-3p, and miR-672-5p). These have the potential to serve as biomarkers of diabetic stroke. These findings provide a new perspective for future research, emphasizing the dynamic changes in miRNA expression after diabetic stroke and offering potential candidates as biomarkers for future clinical applications.

Aberrant splicing of CaV1.2 calcium channel induced by decreased Rbfox1 enhances arterial constriction during diabetic hyperglycemia.

Diabetic hyperglycemia induces dysfunctions of arterial smooth muscle, leading to diabetic vascular complications. The CaV1.2 calcium channel is one primary pathway for Ca2+ influx, which initiates vasoconstriction. However, the long-term regulation mechanism(s) for vascular CaV1.2 functions under hyperglycemic condition remains unknown. Here, Sprague-Dawley rats fed with high-fat diet in combination with low dose streptozotocin and Goto-Kakizaki (GK) rats were used as diabetic models. Isolated mesenteric arteries (MAs) and vascular smooth muscle cells (VSMCs) from rat models were used to assess K+-induced arterial constriction and CaV1.2 channel functions using vascular myograph and whole-cell patch clamp, respectively. K+-induced vasoconstriction is persistently enhanced in the MAs from diabetic rats, and CaV1.2 alternative spliced exon 9* is increased, while exon 33 is decreased in rat diabetic arteries. Furthermore, CaV1.2 channels exhibit hyperpolarized current-voltage and activation curve in VSMCs from diabetic rats, which facilitates the channel function. Unexpectedly, the application of glycated serum (GS), mimicking advanced glycation end-products (AGEs), but not glucose, downregulates the expression of the splicing factor Rbfox1 in VSMCs. Moreover, GS application or Rbfox1 knockdown dynamically regulates alternative exons 9* and 33, leading to facilitated functions of CaV1.2 channels in VSMCs and MAs. Notably, GS increases K+-induced intracellular calcium concentration of VSMCs and the vasoconstriction of MAs. These results reveal that AGEs, not glucose, long-termly regulates CaV1.2 alternative splicing events by decreasing Rbfox1 expression, thereby enhancing channel functions and increasing vasoconstriction under diabetic hyperglycemia. This study identifies the specific molecular mechanism for enhanced vasoconstriction under hyperglycemia, providing a potential target for managing diabetic vascular complications.

Identification and Validation of the Pyroptosis-Related Hub Gene Signature and the Associated Regulation Axis in Diabetic Keratopathy.

Background: Diabetic keratopathy (DK) poses a significant challenge in diabetes mellitus, yet its molecular pathways and effective treatments remain elusive. The aim of our research was to explore the pyroptosis-related genes in the corneal epithelium of the streptozocin-induced diabetic rats. Methods: After sixteen weeks of streptozocin intraperitoneal injection, corneal epithelium from three diabetic rats and three normal groups underwent whole-transcriptome sequencing. An integrated bioinformatics pipeline, including differentially expressed gene (DEG) identification, enrichment analysis, protein-protein interaction (PPI) network, coexpression, drug prediction, and immune deconvolution analyses, identified hub genes and key drivers in DK pathogenesis. These hub genes were subsequently validated in vivo through RT-qPCR. Results: A total of 459 DEGs were screened out from the diabetic group and nondiabetic controls. Gene Set Enrichment Analysis highlighted significant enrichment of the NOD-like receptor, Toll-like receptor, and NF-kappa B signaling pathways. Intersection of DEGs and pyroptosis-related datasets showed 33 differentially expressed pyroptosis-related genes (DEPRGs) associated with pathways such as IL-17, NOD-like receptor, TNF, and Toll-like receptor signaling. A competing endogenous RNA network comprising 16 DEPRGs, 22 lncRNAs, 13 miRNAs, and 3 circRNAs was constructed. After PPI network, five hub genes (Nfkb1, Casp8, Traf6, Ptgs2, and Il18) were identified as upregulated in the diabetic group, and their expression was validated by RT-qPCR in streptozocin-induced rats. Immune infiltration characterization showed that diabetic corneas owned a higher proportion of resting mast cells, activated NK cells, and memory-resting CD4 T cells. Finally, several small compounds including all-trans-retinoic acid, Chaihu Shugan San, dexamethasone, and resveratrol were suggested as potential therapies targeting these hub genes for DK. Conclusions: The identified and validated hub genes, Nfkb1, Casp8, Traf6, Ptgs2, and Il18, may play crucial roles in DK pathogenesis and serve as therapeutic targets.

[Analysis of the types and functions of CD34+ cells in full-thickness skin defect wounds of normal mice and diabetic mice by single-cell RNA sequencing].

Objective: To analyze the types and functions of CD34+ cells in full-thickness skin defect wounds of normal mice and diabetic mice by single-cell RNA sequencing. Methods: This study was an experimental study. The CD34+ cell lineage tracing mouse was produced, and the visualization of CD34+ cells under the fluorescent condition was realized. Six male CD34+ cell lineage tracing mice aged 7-8 weeks (designated as diabetic group) were intraperitoneally injected with streptozotocin to establish a diabetic model, and full-thickness skin defect wounds were prepared on their backs when they reached 13 weeks old. Another 6 male CD34+ cell lineage tracing mice aged 13 weeks (designated as control group) were also subjected to full-thickness skin defect wounds on their backs. On post-injury day (PID) 4, wound tissue was collected from 3 mice in control group and 2 mice in diabetic group, and digested to prepare single-cell suspensions. CD34+ cells were screened using fluorescence-activated cell sorting, followed by single-cell RNA sequencing. The Seurat 4.0.2 program in the R programming language was utilized for dimensionality reduction, visualization, and cell clustering analysis of CD34+ cell types, and to screen and annotate the marker genes for each CD34+ cell subpopulation. Kyoto encyclopedia of genes and genomes (KEGG) and gene ontology (GO) enrichment analysis was performed to analyze the differentially expressed genes (DEGs) of CD34+ fibroblasts (Fbs), smooth muscle cells (SMCs), keratinocytes (KCs), and chondrocyte-like cells (CLCs) in the wound tissue of two groups of mice for exploring cellular functions. Results: On PID 4, CD34+ cells in the wound tissue of both groups of mice were consisted of 7 cell types, specifically endothelial cells, Fbs, KCs, macrophages, T cells, SMCs, and CLCs. Among these, Fbs were further classified into 5 subpopulations. Compared with those in control group, the proportions of CD34+ endothelial cells, Fbs subpopulation 1, Fbs subpopulation 4, KCs, and CLCs in the wound tissue of mice were increased in diabetic group, while the proportions of CD34+ Fbs subpopulation 2, Fbs subpopulation 3, and SMCs were decreased. The marker genes for annotating CD34+ CLCs, endothelial cells, Fbs subpopulation 1, Fbs subpopulation 2, Fbs subpopulation 3, Fbs subpopulation 4, Fbs subpopulation 5, KCs, macrophages, SMCs, and T cells were respectively metastasis-associated lung adenocarcinoma transcript 1, fatty acid binding protein 4, Gremlin 1, complement component 4B, H19 imprinted maternally expressed transcript, Dickkopf Wnt signaling pathway inhibitor 2, fibromodulin, keratin 5, CD74 molecule, regulator of G protein signaling 5, and inducible T-cell co-stimulator molecule. KEGG and GO enrichment analysis revealed that, compared with those in control group, DEGs with significant differential expression (SDE) in CD34+ Fbs from the wound tissue of mice in diabetic group on PID 4 were significantly enriched in terms related to inflammatory response, extracellular matrix (ECM) organization, regulation of cell proliferation, and aging (with Pvalues all <0.05), DEGs with SDE in CD34+ SMCs were significantly enriched in terms related to cell migration, apoptotic process, positive regulation of transcription, and phagosome (with P values all <0.05), DEGs with SDE in CD34+ KCs were significantly enriched in terms related to mitochondrial function, transcription, and neurodegenerative diseases (with P values all <0.05), and DEGs with SDE in CD34+ CLCs were significantly enriched in terms related to rhythm regulation, ECM, and viral infection (with P values all <0.05). Conclusions: CD34+ cells display high heterogeneity in the healing process of full-thickness skin defect wounds in both normal mice and diabetic mice. The significantly enriched functions of DEGs with SDE in CD34+ cell subpopulations in the wound tissue of the two mouse groups are closely related to the wound healing process.

NDUFS4 regulates cristae remodeling in diabetic kidney disease.

The mitochondrial electron transport chain (ETC) is a highly adaptive process to meet metabolic demands of the cell, and its dysregulation has been associated with diverse clinical pathologies. However, the role and nature of impaired ETC in kidney diseases remains poorly understood. Here, we generate diabetic mice with podocyte-specific overexpression of Ndufs4, an accessory subunit of mitochondrial complex I, as a model investigate the role of ETC integrity in diabetic kidney disease (DKD). We find that conditional male mice with genetic overexpression of Ndufs4 exhibit significant improvements in cristae morphology, mitochondrial dynamics, and albuminuria. By coupling proximity labeling with super-resolution imaging, we also identify the role of cristae shaping protein STOML2 in linking NDUFS4 with improved cristae morphology. Together, we provide the evidence on the central role of NDUFS4 as a regulator of cristae remodeling and mitochondrial function in kidney podocytes. We propose that targeting NDUFS4 represents a promising approach to slow the progression of DKD.

Photobiomodulation preconditioned diabetic adipose derived stem cells with additional photobiomodulation: an additive approach for enhanced wound healing in diabetic rats with a delayed healing wound.

In this preclinical investigation, we examined the effects of combining preconditioned diabetic adipose-derived mesenchymal stem cells (AD-MSCs) and photobiomodulation (PBM) on a model of infected ischemic delayed healing wound (injury), (IIDHWM) in rats with type I diabetes (TIDM). During the stages of wound healing, we examined multiple elements such as stereology, macrophage polarization, and the mRNA expression levels of stromal cell-derived factor (SDF)-1α, vascular endothelial growth factor (VEGF), hypoxia-induced factor 1α (HIF-1α), and basic fibroblast growth factor (bFGF) to evaluate proliferation and inflammation. The rats were grouped into: (1) control group; (2) diabetic-stem cells were transversed into the injury site; (3) diabetic-stem cells were transversed into the injury site then the injury site exposed to PBM; (4) diabetic stem cells were preconditioned with PBM and implanted into the wound; (5) diabetic stem cells were preconditioned with PBM and transferred into the injury site, then the injury site exposed additional PBM. While on both days 4, and 8, there were advanced histological consequences in groups 2-5 than in group 1, we found better results in groups 3-5 than in group 2 (p < 0.05). M1 macrophages in groups 2-5 were lower than in group 1, while groups 3-5 were reduced than in group 2 (p < 0.01). M2 macrophages in groups 2-5 were greater than in group 1, and groups 3-5 were greater than in group 2. (p ≤ 0.001). Groups 2-5 revealed greater expression levels of bFGF, VEGF, SDF- 1α, and HIF- 1α genes than in group 1 (p < 0.001). Overall group 5 had the best results for histology (p < 0.05), and macrophage polarization (p < 0.001). AD-MSC, PBM, and AD-MSC + PBM treatments all enhanced the proliferative stage of injury repairing in the IIDHWM in TIDM rats. While AD-MSC + PBM was well than the single use of AD-MSC or PBM, the best results were achieved with PBM preconditioned AD-MSC, plus additional PBM of the injury.

Long noncoding RNA Glis2 regulates podocyte mitochondrial dysfunction and apoptosis in diabetic nephropathy via sponging miR-328-5p.

Podocyte apoptosis exerts a crucial role in the pathogenesis of DN. Recently, long noncoding RNAs (lncRNAs) have been gradually identified to be functional in a variety of different mechanisms associated with podocyte apoptosis. This study aimed to investigate whether lncRNA Glis2 could regulate podocyte apoptosis in DN and uncover the underlying mechanism. The apoptosis rate was detected by flow cytometry. Mitochondrial membrane potential (ΔΨM) was measured using JC-1 staining. Mitochondrial morphology was detected by MitoTracker Deep Red staining. Then, the histopathological and ultrastructure changes of renal tissues in diabetic mice were observed using periodic acid-Schiff (PAS) staining and transmission electron microscopy. We found that lncRNA Glis2 was significantly downregulated in high-glucose cultured podocytes and renal tissues of db/db mice. LncRNA Glis2 overexpression was found to alleviate podocyte mitochondrial dysfunction and apoptosis. The direct interaction between lncRNA Glis2 and miR-328-5p was confirmed by dual luciferase reporter assay. Furthermore, lncRNA Glis2 overexpression alleviated podocyte apoptosis in diabetic mice. Taken together, this study demonstrated that lncRNA Glis2, acting as a competing endogenous RNA (ceRNA) of miRNA-328-5p, regulated Sirt1-mediated mitochondrial dysfunction and podocyte apoptosis in DN.

Sex-specific epigenetics drive low GPER expression in gastrointestinal smooth muscles in type 2 diabetic mice.

Type 2 diabetes mellitus (T2D) causes gastroparesis, delayed intestinal transit, and constipation, for unknown reasons. Complications are predominant in women than men (particularly pregnant and postmenopausal women), suggesting a female hormone-mediated mechanism. Low G-protein coupled estrogen receptor (GPER) expression from epigenetic modifications may explain it. We explored sexually differentiated GPER expression and gastrointestinal symptoms related to GPER alterations in wild-type (WT) and T2D mice (db/db). We also created smooth muscle-specific GPER knockout (GPER KO) mice to phenotypically explore the effect of GPER deficiency on gastrointestinal motility. GPER mRNA and protein expression, DNA methylation and histone modifications were measured from stomach and colon samples of db/db and WT mice. Changes in gut motility were also evaluated as daily fecal pellet production patterns. We found that WT female tissues have the highest GPER mRNA and protein expressions. The expression is lowest in all db/db. GPER downregulation is associated with promoter hypermethylation and reduced enrichment of H3K4me3 and H3K27ac marks around the GPER promoter. We also observed sex-specific disparities in fecal pellet production patterns of the GPER KO mice compared to WT. We thus, conclude that T2D impairs gut GPER expression, and epigenetic sex-specific mechanisms matter in the downregulation.

Appropriate glycemic management protects the germline but not the uterine environment in hyperglycemia.

Emerging evidence indicates that parental diseases can impact the health of subsequent generations through epigenetic inheritance. Recently, it was shown that maternal diabetes alters the metaphase II oocyte transcriptome, causing metabolic dysfunction in offspring. However, type 1 diabetes (T1D) mouse models frequently utilized in previous studies may be subject to several confounding factors due to severe hyperglycemia. This limits clinical translatability given improvements in glycemic control for T1D subjects. Here, we optimize a T1D mouse model to investigate the effects of appropriately managed maternal glycemic levels on oocytes and intrauterine development. We show that diabetic mice with appropriate glycemic control exhibit better long-term health, including maintenance of the oocyte transcriptome and chromatin accessibility. We further show that human oocytes undergoing in vitro maturation challenged with mildly increased levels of glucose, reflecting appropriate glycemic management, also retain their transcriptome. However, fetal growth and placental function are affected in mice despite appropriate glycemic control, suggesting the uterine environment rather than the germline as a pathological factor in developmental programming in appropriately managed diabetes.

Integrated 16S rRNA sequencing and metabolomic analysis reveals the potential protective mechanism of Germacrone on diabetic nephropathy in mice.

Diabetic nephropathy (DN) is a severe complication of diabetes and the leading cause of end-stage renal disease and death. Germacrone (Ger) possesses anti-inflammatory, antioxidant and anti-DN properties. However, it is unclear whether the improvement in kidney damage caused by Ger in DN mice is related to abnormal compositions and metabolites of the gut microbiota. This study generates a mouse model of DN to explore the potent therapeutic ability and mechanism of Ger in renal function by 16S rRNA sequencing and untargeted fecal metabolomics. Although there is no significant change in microbiota diversity, the structure of the gut microbiota in the DN group is quite different. Serratia_marcescens and Lactobacillus_iners are elevated in the model group but significantly decreased after Ger intervention ( P<0.05). Under the treatment of Ger, no significant differences in the diversity and richness of the gut microbiota are observed. An imbalance in the intestinal flora leads to the dysregulation of metabolites, and non-targeted metabolomics data indicate high expression of stearic acid in the DN group, and oleic acid could serve as a potential marker of the therapeutic role of Ger in the DN model. Overall, Ger improves kidney injury in diabetic mice, in part potentially by reducing the abundance of Serratia_marcescens and Lactobacillus_iners, as well as regulating the associated increase in metabolites such as oleic acid, lithocholic acid and the decrease in stearic acid. Our research expands the understanding of the relationship between the gut microbiota and metabolites in Ger-treated DN. This contributes to the usage of natural products as a therapeutic approach for the treatment of DN via microbiota regulation.

Immunomodulation of streptozotocin induced Type 1 diabetes mellitus in mouse model by Macrophage migration inhibitory factor-2 (MIF-2) homologue of human lymphatic filarial parasite, Wuchereria bancrofti.

Helminth parasites modulate the host immune system to ensure a long-lasting asymptomatic form of infection generally, mediated by the secretion of immunomodulatory molecules and one such molecule is a homologue of human host cytokine, Macrophage migratory Inhibitory Factor (hMIF). In this study, we sought to understand the role of homologue of hMIF from the lymphatic filarial parasite, Wuchereria bancrofti (Wba-MIF2), in the immunomodulation of the Streptozotocin (STZ)-induced Type1 Diabetes Mellitus (T1DM) animal model. Full-length recombinant Wba-MIF2 was expressed and found to have both oxidoreductase and tautomerase activities. Wba-MIF2 recombinant protein was treated to STZ induced T1DM animals, and after 5 weeks pro-inflammatory (IL-1, IL-2, IL-6, TNF-α, IFN-γ) and anti-inflammatory (IL-4, IL-10) cytokines and gene expressions were determined in sera samples and spleen respectively. Pro-inflammatory and anti-inflammatory cytokine levels were significantly (p<0.05) up-regulated and down-regulated respectively, in the STZ-T1DM animals, as compared to treated groups. Histopathology showed macrophage infiltration and greater damage of islets of beta cells in the pancreatic tissue of STZ-T1DM animals, than Wba-MIF2 treated STZ-T1DM animals. The present study clearly showed the potential of Wba-MIF2 as an immunomodulatory molecule, which could modulate the host immune system in the STZ-T1DM mice model from a pro-inflammatory to anti-inflammatory milieu.

Sorbs2 Deficiency and Vascular BK Channelopathy in Diabetes.

BACKGROUND: Vascular large conductance Ca2+-activated K+ (BK) channel, composed of the α-subunit (BK-α) and the ß1-subunit (BK-ß1), is a key determinant of coronary vasorelaxation and its function is impaired in diabetic vessels. However, our knowledge of diabetic BK channel dysregulation is incomplete. The Sorbs2 (Sorbin homology [SoHo] and Src homology 3 [SH3] domains-containing protein 2), is ubiquitously expressed in arteries, but its role in vascular pathophysiology is unknown. METHODS: The role of Sorbs2 in regulating vascular BK channel activity was determined using patch-clamp recordings, molecular biological techniques, and in silico analysis. RESULTS: Sorbs2 is not only a cytoskeletal protein but also an RNA-binding protein that binds to BK channel proteins and BK-α mRNA, regulating BK channel expression and function in coronary smooth muscle cells. Molecular biological studies reveal that the SH3 domain of Sorbs2 is necessary for Sorbs2 interaction with BK-α subunits, while both the SH3 and SoHo domains of Sorbs2 interact with BK-ß1 subunits. Deletion of the SH3 or SoHo domains abolishes the Sorbs2 effect on the BK-α/BK-ß1 channel current density. Additionally, Sorbs2 is a target gene of the Nrf2 (nuclear factor erythroid-2-related factor 2), which binds to the promoter of Sorbs2 and regulates Sorbs2 expression in coronary smooth muscle cells. In vivo studies demonstrate that Sorbs2 knockout mice at 4 months of age display a significant decrease in BK channel expression and function, accompanied by impaired BK channel Ca2+-sensitivity and BK channel-mediated vasodilation in coronary arteries, without altering their body weights and blood glucose levels. Importantly, Sorbs2 expression is significantly downregulated in the coronary arteries of db/db type 2 diabetic mice. CONCLUSIONS: Sorbs2, a downstream target of Nrf2, plays an important role in regulating BK channel expression and function in vascular smooth muscle cells. Vascular Sorbs2 is downregulated in diabetes. Genetic knockout of Sorbs2 manifests coronary BK channelopathy and vasculopathy observed in diabetic mice, independent of obesity and glucotoxicity.

Roles of ferroptosis in type 1 diabetes induced spermatogenic dysfunction.

Diabetes mellitus (DM) is a widespread metabolic disease presenting with various complications, including spermatogenic dysfunction. However, the underlying mechanisms are still unclear. Ferroptosis, a novel type of programmed cell death, is associated with much metabolic diseases. Here, we investigated the role of ferroptosis in spermatogenic dysfunction of streptozotocin (STZ)-induced type 1 diabetic mice (diabetic mice), high glucose (HG)-treated GC-2 cells (HG cells) as well as testicular tissues of diabetic patients. We found an accumulation of iron, elevated malondialdehyde level and reduced glutathione level in the testis tissues of diabetic mice and HG cells. Histological examination showed a decrease in spermatogenic cells and spermatids within the seminiferous tubules as well as mitochondrial shrinkage in the testis tissues of diabetic mice. Ferrostatin-1 (Fer-1), the inhibitor of ferroptosis, mitigated ferroptosis-associated iron overload, lipid peroxidation accumulation and spermatogenic dysfunction of diabetic mice. Furthermore, we observed a downregulation of GPX4, FTL and SLC7A11 in diabetic mice and HG cells. Fer-1 treatment and GPX4 overexpression counteracted the effects of HG on cell viability, reactive oxygen species, lipid peroxidation and glutathione via inhibition of ferroptosis. Moreover, we found an elevation of ferroptosis in testicular tissues of diabetic patients. Taken together, our results identify the crucial role of ferroptosis in diabetic spermatogenic dysfunction and ferroptosis may be a promising therapeutic target to improve spermatogenesis in diabetic patients.

Zbtb16 increases susceptibility of atrial fibrillation in type 2 diabetic mice via Txnip-Trx2 signaling.

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, and recent epidemiological studies suggested type 2 diabetes mellitus (T2DM) is an independent risk factor for the development of AF. Zinc finger and BTB (broad-complex, tram-track and bric-a-brac) domain containing 16 (Zbtb16) serve as transcriptional factors to regulate many biological processes. However, the potential effects of Zbtb16 in AF under T2DM condition remain unclear. Here, we reported that db/db mice displayed higher AF vulnerability and Zbtb16 was identified as the most significantly enriched gene by RNA sequencing (RNA-seq) analysis in atrium. In addition, thioredoxin interacting protein (Txnip) was distinguished as the key downstream gene of Zbtb16 by Cleavage Under Targets and Tagmentation (CUT&Tag) assay. Mechanistically, increased Txnip combined with thioredoxin 2 (Trx2) in mitochondrion induced excess reactive oxygen species (ROS) release, calcium/calmodulin-dependent protein kinase II (CaMKII) overactivation, and spontaneous Ca2+ waves (SCWs) occurrence, which could be inhibited through atrial-specific knockdown (KD) of Zbtb16 or Txnip by adeno-associated virus 9 (AAV9) or Mito-TEMPO treatment. High glucose (HG)-treated HL-1 cells were used to mimic the setting of diabetic in vitro. Zbtb16-Txnip-Trx2 signaling-induced excess ROS release and CaMKII activation were also verified in HL-1 cells under HG condition. Furthermore, atrial-specific Zbtb16 or Txnip-KD reduced incidence and duration of AF in db/db mice. Altogether, we demonstrated that interrupting Zbtb16-Txnip-Trx2 signaling in atrium could decrease AF susceptibility via reducing ROS release and CaMKII activation in the setting of T2DM.

Altered N6-Methyladenosine Modification Patterns and Transcript Profiles Contributes to Cognitive Dysfunction in High-Fat Induced Diabetic Mice.

N6-methyladenosine (m6A) constitutes the paramount post-transcriptional modification within eukaryotic mRNA. This modification is subjected to stimulus-dependent regulation within the central nervous system of mammals, being influenced by sensory experiences, learning processes, and injuries. The patterns of m6A methylation within the hippocampal region of diabetes cognitive impairment (DCI) has not been investigated. A DCI model was established by feeding a high-fat diet to C57BL/6J mice. m6A and RNA sequencing was conducted to profile the m6A-tagged transcripts in the hippocampus. Methylated RNA immunoprecipitation with next-generation sequencing and RNA sequencing analyses yielded differentially m6A-modified and expressed genes in the hippocampus of DCI mice, which were enriched in pathways involving synaptic transmission and axonal guidance. Mechanistic analyses revealed a remarkable change in m6A modification levels through alteration of the mRNA expression of m6A methyltransferases (METTL3 and METTL14) and demethylase (FTO) in the hippocampus of DCI mice. We identified a co-mediated specific RNA regulatory strategy that broadens the epigenetic regulatory mechanism of RNA-induced neurodegenerative disorders associated with metabolic and endocrine diseases.

Sustained Effectiveness and Safety of Therapeutic miR-10a/b in Alleviating Diabetes and Gastrointestinal Dysmotility without Inducing Cancer or Inflammation in Murine Liver and Colon.

microRNAs (miRNAs) are key regulators of both physiological and pathophysiological mechanisms in diabetes and gastrointestinal (GI) dysmotility. Our previous studies have demonstrated the therapeutic potential of miR-10a-5p mimic and miR-10b-5p mimic (miR-10a/b mimics) in rescuing diabetes and GI dysmotility in murine models of diabetes. In this study, we elucidated the safety profile of a long-term treatment with miR-10a/b mimics in diabetic mice. Male C57BL/6 mice were fed a high-fat, high-sucrose diet (HFHSD) to induce diabetes and treated by five subcutaneous injections of miR-10a/b mimics for a 5 month period. We examined the long-term effects of the miRNA mimics on diabetes and GI dysmotility, including an assessment of potential risks for cancer and inflammation in the liver and colon using biomarkers. HFHSD-induced diabetic mice subcutaneously injected with miR-10a/b mimics on a monthly basis for 5 consecutive months exhibited a marked reduction in fasting blood glucose levels with restoration of insulin and significant weight loss, improved glucose and insulin intolerance, and restored GI transit time. In addition, the miR-10a/b mimic-treated diabetic mice showed no indication of risk for cancer development or inflammation induction in the liver, colon, and blood for 5 months post-injections. This longitudinal study demonstrates that miR-10a/b mimics, when subcutaneously administered in diabetic mice, effectively alleviate diabetes and GI dysmotility for 5 months with no discernible risk for cancer or inflammation in the liver and colon. The sustained efficacy and favorable safety profiles position miR-10a/b mimics as promising candidates in miRNA-based therapeutics for diabetes and GI dysmotility.

Genome-wide screening of m6A profiling of cutaneous wound healing in diabetic mice.

OBJECTIVE: Impaired wound healing in diabetes mellitus (DM) is a major health burden on patients, their families, and society. The present study aimed to systematically profile the m6A modification landscape in cutaneous wounds in a diabetic mouse model. APPROACH: Diabetes was induced in mice through a single intraperitoneal injection of streptozotocin (STZ); a single intraperitoneal injection of PBS was made in control mice for comparisons. Both groups then received an 8-mm diameter, full-thickness dorsal body wound with a biopsy punch. Five days after wound surgery, western blot analysis of harvested wound tissues from both groups was used to assess the expression of m6A-related enzymes. Genome-wide profiling of m6A-tagged transcripts was performed through MeRIP-seq and RNA-seq. RESULTS: ALKBH5, an m6A eraser, was significantly upregulated, while METTL3, METTL14, and WTAP, m6A writers, were markedly downregulated in the diabetic wounds. Additionally, a total of 1335 m6A peaks were differentially expressed in MeRIP-seq and RNA-seq analyses, with 558 upregulated and 777 downregulated peaks. Finally, there was hypomethylated and hypermethylated differentiation at the gene and transcript levels. INNOVATION: The present study was the first to reveal the m6A landscape in diabetic wounds in an animal model. CONCLUSION: This study, by deeply analyzing the role of m6A modifications in diabetic wound healing, provides new insights and understanding into the molecular mechanisms of diabetic wound healing. Future research could further explore how m6A modifications regulate the wound healing process, thereby offering new potential targets for the treatment of diabetic wounds.

Transthyretin-Regulated Diabetic Retinopathy Through the VEGFA/PI3K/AKT Pathway.

Purpose: Transthyretin (TTR) plays a regulatory role in a variety of diabetes-related diseases. The objective of this work was to probe whether TTR affects diabetic retinopathy (DR) through the VEGFA/PI3K/AKT pathway. Methods: High glucose (HG, 25 mM) was used to treat human retinal microvascular endothelial cells (hRMECs) and C57BL/6J mice were intraperitoneally injected with STZ (50 mg/kg) to construct a DR model. In vitro, the effect of TTR on DR was evaluated by measuring hRMEC proliferation, migration, and angiogenesis. The changes in retinal tissue were observed by hematoxylin and eosin staining in vivo. ELISA, immunohistochemistry, and immunofluorescence staining were used to measure VEGFA or CD31 levels. The levels of all proteins were evaluated through Western blot. Results: The increase of proliferation, migration, and angiogenesis and decrease of apoptosis in hRMECs caused by HG were notably reversed by TTR. TTR greatly impeded HG-raised VEGFA, PI3K p-p85, and p-AKT in hRMECs. Inhibition of TTR further exacerbated the effect of HG-induced hRMECs. Inhibition of VEGFA reversed the effect of HG-induced hRMECs. VEGFA neutralized the function of TTR on cell proliferation, apoptosis, migration, and angiogenesis in HG-triggered hRMECs. It was further confirmed in vivo that TTR can alleviate the occurrence of DR in diabetic mice models. Conclusions: TTR significantly restrained the progression of DR via molecular modulation of the VEGFA/PI3K/AKT axis.

IGF2BP3-stabilized CAMK1 regulates the mitochondrial dynamics of renal tubule to alleviate diabetic nephropathy.

BACKGROUND: CAMK1 has been shown to be involved in human disease progression via regulating mitochondrial dynamics. However, whether CAMK1 mediates mitochondrial dynamics to regulate diabetic nephropathy (DN) process remains unclear. METHODS: Mice were injected with streptozotocin (STZ) to mimic diabetic mice models in vivo, and mice with proximal tubule-specific knockout of CAMK1 (CAMK1-KO) were generated. HK-2 cells were treated with high-glucose (HG) to mimic DN cell model in vitro. Histopathological analysis was performed to confirm kidney injury in mice. ROS production and apoptosis were assessed by DHE staining and TUNEL staining. Mitochondria morphology was observed and analyzed by electron microscopy. Mitochondrial membrane potential was detected by JC-1 staining, and cell proliferation was measured by EdU assay. The mRNA and protein expression were examined by qRT-PCR, western blot and immunostaining. RNA interaction was confirmed by RIP assay and dual-luciferase reporter assay. The mRNA stability was tested by actinomycin D treatment, and m6A level was examined by MeRIP assay. RESULTS: CAMK1 was reduced in DN patients and STZ-induced diabetic mice. Conditional deletion of CAMK1 aggravated kidney injury and promoted mitochondrial fission in diabetic mice. CAMK1 overexpression inhibited mitochondrial fission to alleviate HG-induced HK-2 cell apoptosis. IGF2BP3 promoted the stability of CAMK1 mRNA by m6A modification. IGF2BP3 inhibited mitochondrial fission to repress cell apoptosis in vitro and kidney injury in vivo by increasing CAMK1 expression. CONCLUSION: IGF2BP3-mediated CAMK1 mRNA stability alleviated DN progression by inhibiting mitochondria fission.

Implication of lncRNA MSTRG.81401 in Hippocampal Pyroptosis Induced by P2X7 Receptor in Type 2 Diabetic Rats with Neuropathic Pain Combined with Depression.

Major depressive disorder (MDD) is a common complication of diabetes and is often observed alongside diabetic neuropathic pain (DNP) as a comorbidity in diabetic patients. Long non-coding RNA (lncRNA) plays an important role in various pathophysiological processes. The P2X7 receptor is responsible for triggering inflammatory responses, such as pyroptosis, linked to pain and depression. The aim of this study was to investigate the effect of lncRNA MSTRG.81401 on hippocampal pyroptosis induced by the P2X7 receptor in diabetic rats with DNP combined with MDD (DNP + MDD). Our results showed that the expression of lncRNA MSTRG.81401 was significantly elevated in the hippocampus of DNP + MDD rats compared with the control group. Following the administration of shRNA targeting lncRNA MSTRG.81401, a notable elevation in mechanical and thermal pain thresholds was observed in rats with comorbid DNP and MDD. Additionally, significant improvements in depression-like behaviors were evident in the open-field test (OFT), sucrose preference test (SPT), and forced swim test (FST). In the DNP + MDD rats, elevated levels in hippocampal P2X7 receptor mRNA and protein were observed, along with increased co-expression of P2X7 and the astrocytic marker glial fibrillary acidic protein (GFAP). Meanwhile, in DNP + MDD rats, the heightened mRNA expression of NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), pyroptosis-related protein Gasdermin D (GSDMD), caspase-1, IL-1ß, IL-18, and TNF-α was detected, in addition to increased serum levels of IL-1ß, IL-18 and TNF-α. After shRNA treatment with lncRNA MSTRG.81401, the above abnormal changes in indicators for pyroptosis and inflammation were improved. Therefore, our study demonstrates that shRNA of lncRNA MSTRG.81401 can alleviate the pain and depression-like behaviors in diabetic rats associated with the comorbidity of DNP and MDD by inhibiting the hippocampal P2X7 receptor-mediated pyroptosis pathway and pro-inflammatory responses. This suggests that the P2X7R/NLRP3/caspase-1 implicated pyroptosis and inflammatory scenario may serve as a potential target for the management of comorbid DNP and MDD in diabetes.