Altered Gut Microbiota as a Potential Risk Factor for Coronary Artery Disease in Diabetes: A Two-Sample Bi-Directional Mendelian Randomization Study.

The current body of research points to a notable correlation between an imbalance in gut microbiota and the development of type 2 diabetes mellitus (T2D) as well as its consequential ailment, coronary artery disease (CAD). The complexities underlying the association, especially in the context of diabetic coronary artery disease (DCAD), are not yet fully understood, and the causal links require further clarification. In this study, a bidirectional Mendelian randomization (MR) methodology was utilized to explore the causal relationships between gut microbiota, T2D, and CAD. By analyzing data from the DIAGRAM, GERA, UKB, FHS, and mibioGen cohorts and examining GWAS databases, we sought to uncover genetic variants linked to T2D, CAD, and variations in gut microbiota and metabolites, aiming to shed light on the potential mechanisms connecting gut microbiota with DCAD. Our investigation uncovered a marked causal link between the presence of Oxalobacter formigenes and an increased incidence of both T2D and CAD. Specifically, a ten-unit genetic predisposition towards T2D was found to be associated with a 6.1% higher probability of an increase in the Oxalobacteraceae family's presence (ß = 0.061, 95% CI = 0.002-0.119). In a parallel finding, an augmented presence of Oxalobacter was related to an 8.2% heightened genetic likelihood of CAD (ß = 0.082, 95% CI = 0.026-0.137). This evidence indicates a critical pathway by which T2D can potentially raise the risk of CAD via alterations in gut microbiota. Additionally, our analyses reveal a connection between CAD risk and Methanobacteria, thus providing fresh perspectives on the roles of TMAO and carnitine in the etiology of CAD. The data also suggest a direct causal relationship between increased levels of certain metabolites - proline, lysophosphatidylcholine, asparagine, and salicylurate - and the prevalence of both T2D and CAD. Sensitivity assessments reinforce the notion that changes in Oxalobacter formigenes could pose a risk for DCAD. There is also evidence to suggest that DCAD may, in turn, affect the gut microbiota's makeup. Notably, a surge in serum TMAO levels in individuals with CAD, coinciding with a reduced presence of methanogens, has been identified as a potentially significant factor for future examination.

The association of FGF-21 with the risk of newly diagnosed type-2 diabetes mellitus: a cross-sectional study in Southern China.

BACKGROUND: This study investigated the relationship between fibroblast growth factor 21 (FGF-21) and newly diagnosed type-2 diabetes mellitus (T2DM). METHODS: In this cross-sectional study, FGF-21 and T2DM risk were analyzed using restricted cubic splines with univariate or multivariate logistic regression analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated via logistic regression analysis. Cluster and subgroup analyses were conducted to evaluate the associations between FGF-21 and diabetes in different subpopulations. Nomograms and ROC curves were used to explore the clinical utility of FGF-21 in the diabetes assessment model. RESULTS: High levels of FGF-21 were significantly associated with a high risk of T2DM after adjusting for confounding factors in both the total population and subpopulations (P for trend < 0.001). In the total population, the ORs of diabetes with increasing FGF-21 quartiles were 1.00 (reference), 1.24 (95% CI 0.56-2.80; quartile 2), 2.47 (95% CI 1.18-5.33; quartile 3), and 3.24 (95% CI 1.53-7.14; quartile 4) in Model 4 (P < 0.001), and the trend was consistent in different subpopulations. In addition, compared with the model constructed with conventional noninvasive indicators, the AUC of the model constructed by adding FGF-21 was increased from 0.668 (95% CI: 0.602-0.733) to 0.715 (95% CI: 0.654-0.777), indicating that FGF-21 could significantly improve the risk-assessment efficiency of type-2 diabetes. CONCLUSION: This study demonstrated that a high level of circulating FGF-21 was positively correlated with diabetes, and levels of FGF-21 could be an important biomarker for the assessment of diabetes risk.

Metformin inhibits TGF-beta 1-induced MCP-1 expression through BAMBI-mediated suppression of MEK/ERK1/2 signalling.

AIMS: Metformin is a biguanide derivative widely used for the treatment of type 2 diabetes mellitus. Recent evidence demonstrates that this anti-hyperglycaemic drug exerts renal protective effects, yet the mechanisms remain poorly understood. monocyte chemoattractant protein 1 (MCP-1) has been recognized as a key mediator of renal fibrosis in chronic kidney diseases, including diabetic nephropathy. This study aimed to investigate the effects of metformin on transforming growth factor beta 1 (TGF-ß1)-induced MCP-1 expression and the underlying mechanisms in rat renal tubular epithelial cells. METHODS: Rat renal tubular epithelial cell line NRK-52E cells were stimulated with TGF-ß1 and/or metformin. The messenger RNA (mRNA) of MCP-1 and bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) was evaluated by real-time quantitative polymerase chain reaction. MCP-1 protein was measured by enzyme linked immunosorbent assay (ELISA). Total and phosphorylated extracellular signal-regulated kinases 1/2 (ERK1/2) was evaluated by western blot. Down- and upregulation of BAMBI were achieved by RNA interference targeting BAMBI and lentiviral vector-mediated overexpression of the BAMBI gene, respectively. Cell viability was analysed using Cell Counting Kit 8 (CCK-8) reagents. RESULTS: Stimulation with TGF-ß1 resulted in the increased expression of MCP-1 and decreased expression of BAMBI in NRK-52E cells. Metformin inhibited the expression of MCP-1 in NRK-52E cells. Pretreatment with metformin suppressed upregulation of MCP-1 and downregulation of BAMBI, as well as phosphorylation of ERK1/2 induced by TGF-ß1. U0126, a specific inhibitor for mitogen-activated and extracellular signal-regulated kinase kinases 1/2 (MEK-1/2), completely blocked TGF-ß1-induced MCP-1 expression. Knockdown of the BAMBI gene promoted phosphorylation of ERK1/2 and TGF-ß1-induced expression of MCP-1. Overexpression of BAMBI inhibited phosphorylation of ERK1/2 and TGF-ß1-induced upregulation of MCP-1. CONCLUSION: In rat renal tubular epithelial cells, metformin prevents TGF-ß1-induced MCP-1 expression, in which BAMBI-mediated inhibition of MEK/ERK1/2 might be involved.

Keratinocyte-derived small extracellular vesicles delay diabetic wound healing by triggering fibroblasts autophagy.

Keratinocyte and fibroblast dysfunctions contribute to delayed healing of diabetic wounds. Small extracellular vesicles (sEV) are key mediators of intercellular communication and are involved in the pathogenesis of several diseases. Recent findings suggest that sEV derived from high-glucose-treated keratinocyte (HaCaT-HG-sEV) can transport LINC01435 to inhibit tube formation and migration of HUVECs, thereby delaying wound healing. This study aimed to elucidate sEV-related communication mechanisms between keratinocytes and fibroblasts during diabetic wound healing. HaCaT-HG-sEV treatment and LINC01435 overexpression significantly decreased fibroblast collagen level and migration ability but significantly increased fibroblast autophagy. However, treatment with an autophagy inhibitor suppressed LINC01435 overexpression-induced decrease in collagen levels in fibroblasts. In diabetic mice, HaCaT-HG-sEV treatment decreased collagen levels and increased the expression of the autophagy-related proteins Beclin-1 and LC3 at the wound site, thereby delaying wound healing. Conclusively, LINC01435 in keratinocyte-derived sEV activates fibroblast autophagy and reduces fibroblast collagen synthesis, leading to impaired diabetic wound healing.

Diabetic foot ulcers are a serious complication of diabetes and can lead to amputation and death. Therefore, it is crucial to comprehensively elucidate the mechanisms of delayed diabetic wound healing, with emphasis on the role of keratinocyte-derived small extracellular vesicles. In vivo and in vitro experiments showed that keratinocyte-derived small extracellular vesicles suppressed diabetic wound healing, which is partly attributed to the effects of their content (LINC01435) in fibroblasts. This study suggests that LINC01435 could be targeted to regulate diabetic wound healing.

Erratum: Long noncoding RNA LINC01435 impedes diabetic wound healing by facilitating YY1-mediated HDAC8 expression.

[This corrects the article DOI: 10.1016/j.isci.2022.104006.].

Long noncoding RNA LINC01435 impedes diabetic wound healing by facilitating YY1-mediated HDAC8 expression.

Abnormal interactions between skin cells play an important role in the dysregulation of diabetic wound recovery. Exosomes are cell-derived lipid nanoparticles that transport messages between cells, and isolating and identifying potential therapeutic noncoding RNAs from exosomes is very important. We demonstrated that treatment with Exos from high glucose-pretreated immortalized human epidermal (HaCaT) cells (HG-Exos) could delay the wound healing process in diabetic mice. Further analysis indicated the Exo-mediated uptake of LINC01435 in recipient human umbilical vein endothelial cells (HUVECs) changes the subcellular localization of the transcription factor Yin Yang 1 (YY1) and cooperates with YY1 to upregulate the expression of histone deacetylases (HDACs)8, resulting in decreased tube formation and ability of HUVECs to migrate, thus angiogenesis was inhibited. These results suggest that LINC01435/YY1/HDAC8 may be an important signaling pathway affecting the recovery of diabetic wounds, which makes it a potential target for the treatment of diabetic foot ulcers.

m6A reader YTHDC1 modulates autophagy by targeting SQSTM1 in diabetic skin.

Dysregulation of macroautophagy/autophagy contributes to the delay of wound healing in diabetic skin. N6-methyladenosine (m6A) RNA modification is known to play a critical role in regulating autophagy. In this study, it was found that SQSTM1/p62 (sequestosome 1), an autophagy receptor, was significantly downregulated in two human keratinocyte cells lines with short-term high-glucose treatment, as well as in the epidermis of diabetic patients and a db/db mouse model with long-term hyperglycemia. Knockdown of SQSTM1 led to the impairment of autophagic flux, which was consistent with the results of high-glucose treatment in keratinocytes. Moreover, the m6A reader protein YTHDC1 (YTH domain containing 1), which interacted with SQSTM1 mRNA, was downregulated in keratinocytes under both the acute and chronic effects of hyperglycemia. Knockdown of YTHDC1 affected biological functions of keratinocytes, which included increased apoptosis rates and impaired wound-healing capacity. In addition, knockdown of endogenous YTHDC1 resulted in a blockade of autophagic flux in keratinocytes, while overexpression of YTHDC1 rescued the blockade of autophagic flux induced by high glucose. In vivo, knockdown of endogenous Ythdc1 or Sqstm1 inhibited autophagy in the epidermis and delayed wound healing. Interestingly, we found that a decrease of YTHDC1 drove SQSTM1 mRNA degradation in the nucleus. Furthermore, the results revealed that YTHDC1 interacted and cooperated with ELAVL1/HuR (ELAV like RNA binding protein 1) in modulating the expression of SQSTM1. Collectively, this study uncovered a previously unrecognized function for YTHDC1 in modulating autophagy via regulating the stability of SQSTM1 nuclear mRNA in diabetic keratinocytes.Abbreviations: ACTB: actin beta; AGEs: glycation end products; AL: autolysosome; AP: autophagosome; ATG: autophagy related; AKT: AKT serine/threonine kinase; ANOVA: analysis of variance; BECN1: beclin 1; Co-IP: co-immunoprecipitation; DEGs: differentially expressed genes; DM: diabetes mellitus; ELAVL1: ELAV like RNA binding protein 1; FTO: FTO alpha-ketoglutarate dependent dioxygenase; G: glucose; HaCaT: human keratinocyte; GO: Gene Ontology; GSEA: Gene Set Enrichment Analysis; HE: hematoxylin-eosin; IHC: immunohistochemical; IRS: immunoreactive score; KEAP1: kelch like ECH associated protein 1; KEGG: Kyoto Encyclopedia of Genes and Genomes; m6A: N6-methyladenosine; M: mannitol; MANOVA: multivariate analysis of variance; MAP1LC3: microtubule associated protein 1 light chain 3; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MeRIP: methylated RNA immunoprecipitation; METTL3: methyltransferase 3, N6-adenosine-methytransferase complex catalytic subunit; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin complex 1; NBR1: NBR1 autophagy cargo receptor; NFE2L2: nuclear factor, erythroid 2 like 2; NG: normal glucose; NHEK: normal human epithelial keratinocyte; OE: overexpressing; p-: phospho-; PI: propidium iodide; PPIN: Protein-Protein Interaction Network; RBPs: RNA binding proteins; RIP: RNA immunoprecipitation; RNA-seq: RNA-sequence; RNU6-1: RNA, U6 small nuclear 1; ROS: reactive oxygen species; siRNAs: small interfering RNAs; SQSTM1: sequestosome 1; SRSF: serine and arginine rich splicing factor; T2DM: type 2 diabetes mellitus; TEM: transmission electron microscopy; TUBB: tubulin beta class I; WT: wild-type; YTHDC1: YTH domain containing 1.

BTK Promotes Atherosclerosis by Regulating Oxidative Stress, Mitochondrial Injury, and ER Stress of Macrophages.

Atherosclerosis (AS) is a chronic metabolic disease in arterial walls, characterized by lipid deposition and persistent aseptic inflammation. AS is regarded as the basis of a variety of cardiovascular and cerebrovascular diseases. It is widely acknowledged that macrophages would become foam cells after internalizing lipoprotein particles, which is an initial factor in atherogenesis. Here, we showed the influences of Bruton's tyrosine kinase (BTK) in macrophage-mediated AS and how BTK regulates the inflammatory responses of macrophages in AS. Our bioinformatic results suggested that BTK was a potential hub gene, which is closely related to oxidative stress, ER stress, and inflammation in macrophage-induced AS. Moreover, we found that BTK knockdown could restrain ox-LDL-induced NK-κB signaling activation in macrophages and repressed M1 polarization. The mechanistic studies revealed that oxidative stress, mitochondrial injury, and ER stress in macrophages were also suppressed by BTK knockdown. Furthermore, we found that sh-BTK adenovirus injection could alleviate the severity of AS in ApoE-/- mice induced by a high-fat diet in vivo. Our study suggested that BTK promoted ox-LDL-induced ER stress, oxidative stress, and inflammatory responses in macrophages, and it may be a potential therapeutic target in AS.