SETD8 cooperates with MZF1 to participate in hyperglycemia-induced endothelial inflammation via elevation of WNT5A levels in diabetic nephropathy

Liver sinusoidal endothelial cells rely on oxidative phosphorylation but avoid processing long-chain fatty acids in their mitochondria

BACKGROUND

It is generally accepted that endothelial cells (ECs), primarily rely on glycolysis for ATP production, despite having functional mitochondria. However, it is also known that ECs are heterogeneous, and their phenotypic features depend on the vascular bed. Emerging evidence suggests that liver sinusoidal ECs (LSECs), located in the metabolically rich environment of the liver, show high metabolic plasticity. However, the substrate preference for energy metabolism in LSECs remains unclear.

METHODS

Investigations were conducted in primary murine LSECs in vitro using the Seahorse XF technique for functional bioenergetic assays, untargeted mass spectrometry-based proteomics to analyse the LSEC proteome involved in energy metabolism pathways, liquid chromatography-tandem mass spectrometry-based analysis of acyl-carnitine species and Raman spectroscopy imaging to track intracellular palmitic acid.

RESULTS

This study comprehensively characterized the energy metabolism of LSECs, which were found to depend on oxidative phosphorylation, efficiently fuelled by glucose-derived pyruvate, short- and medium-chain fatty acids and glutamine. Furthermore, despite its high availability, palmitic acid was not directly oxidized in LSEC mitochondria, as evidenced by the acylcarnitine profile and etomoxir's lack of effect on oxygen consumption. However, together with L-carnitine, palmitic acid supported mitochondrial respiration, which is compatible with the chain-shortening role of peroxisomal β-oxidation of long-chain fatty acids before further degradation and energy generation in mitochondria.

CONCLUSIONS

LSECs show a unique bioenergetic profile of highly metabolically plastic ECs adapted to the liver environment. The functional reliance of LSECs on oxidative phosphorylation, which is not a typical feature of ECs, remains to be determined.

Endothelial dysfunction in vascular complications of diabetes: a comprehensive review of mechanisms and implications

Diabetic vascular complications are prevalent and severe among diabetic patients, profoundly affecting both their quality of life and long-term prospects. These complications can be classified into macrovascular and microvascular complications. Under the impact of risk factors such as elevated blood glucose, blood pressure, and cholesterol lipids, the vascular endothelium undergoes endothelial dysfunction, characterized by increased inflammation and oxidative stress, decreased NO biosynthesis, endothelial-mesenchymal transition, senescence, and even cell death. These processes will ultimately lead to macrovascular and microvascular diseases, with macrovascular diseases mainly characterized by atherosclerosis (AS) and microvascular diseases mainly characterized by thickening of the basement membrane. It further indicates a primary contributor to the elevated morbidity and mortality observed in individuals with diabetes. In this review, we will delve into the intricate mechanisms that drive endothelial dysfunction during diabetes progression and its associated vascular complications. Furthermore, we will outline various pharmacotherapies targeting diabetic endothelial dysfunction in the hope of accelerating effective therapeutic drug discovery for early control of diabetes and its vascular complications.

NDUFA8 is transcriptionally regulated by EP300/H3K27ac and promotes mitochondrial respiration to support proliferation and inhibit apoptosis in cervical cancer

Cervical cancer, a common malignancy in women, poses a significant health burden worldwide. In this study, we aimed to investigate the expression, function, and potential mechanisms of NADH: ubiquinone oxidoreductase subunit A8 (NDUFA8) in cervical cancer. The Gene Expression Profiling Interactive Analysis (GEPIA) database and immunohistochemical scoring were used to analyze NDUFA8 expression in cervical cancer tissues and normal tissues. Quantitative real-time PCR and Western blot analyses were performed to assess the expression level of NDUFA8 in cervical cancer cell lines. NDUFA8 knockdown or overexpression experiments were conducted to evaluate its impact on cell proliferation and apoptosis. The mitochondrial respiratory status was analyzed by measuring cellular oxygen consumption, adenosine triphosphate (ATP) levels, and the expression levels of Mitochondrial Complex I activity, and Mitochondrial Complex IV-associated proteins Cytochrome C Oxidase Subunit 5B (COX5B) and COX6C. NDUFA8 exhibited high expression levels in cervical cancer tissues, and these levels were correlated with reduced survival rates. A significant upregulation of NDUFA8 expression was observed in cervical cancer cell lines compared to normal cells. Silencing NDUFA8 hindered cell proliferation, promoted apoptosis, and concurrently suppressed cellular mitochondrial respiration, resulting in decreased levels of available ATP. Conversely, NDUFA8 overexpression induced the opposite effects. Herein, we also found that E1A Binding Protein P300 (EP300) overexpression facilitated Histone H3 Lysine 27 (H3K27) acetylation enrichment, enhancing the activity of the NDUFA8 promoter region. NDUFA8, which is highly expressed in cervical cancer, is regulated by transcriptional control via EP300/H3K27 acetylation. By promoting mitochondrial respiration, NDUFA8 contributes to cervical cancer cell proliferation and apoptosis. These findings provide novel insights into NDUFA8 as a therapeutic target in cervical cancer.

(Pro)renin receptor mediates tubular epithelial cell pyroptosis in diabetic kidney disease via DPP4-JNK pathway

BACKGROUND

(Pro)renin receptor (PRR) is highly expressed in renal tubules, which is involved in physiological and pathological processes. However, the role of PRR, expressed in renal tubular epithelial cells, in diabetic kidney disease (DKD) remain largely unknown.

METHODS

In this study, kidney biopsies, urine samples, and public RNA-seq data from DKD patients were used to assess PRR expression and cell pyroptosis in tubular epithelial cells. The regulation of tubular epithelial cell pyroptosis by PRR was investigated by in situ renal injection of adeno-associated virus9 (AAV9)-shRNA into db/db mice, and knockdown or overexpression of PRR in HK-2 cells. To reveal the underlined mechanism, the interaction of PRR with potential binding proteins was explored by using BioGrid database. Furthermore, the direct binding of PRR to dipeptidyl peptidase 4 (DPP4), a pleiotropic serine peptidase which increases blood glucose by degrading incretins under diabetic conditions, was confirmed by co-immunoprecipitation assay and immunostaining.

RESULTS

Higher expression of PRR was found in renal tubules and positively correlated with kidney injuries of DKD patients, in parallel with tubular epithelial cells pyroptosis. Knockdown of PRR in kidneys significantly blunted db/db mice to kidney injury by alleviating renal tubular epithelial cells pyroptosis and the resultant interstitial inflammation. Moreover, silencing of PRR blocked high glucose-induced HK-2 pyroptosis, whereas overexpression of PRR enhanced pyroptotic cell death of HK-2 cells. Mechanistically, PRR selectively bound to cysteine-enrich region of C-terminal of DPP4 and augmented the protein abundance of DPP4, leading to the downstream activation of JNK signaling and suppression of SIRT3 signaling and FGFR1 signaling, and then subsequently mediated pyroptotic cell death.

CONCLUSIONS

This study identified the significant role of PRR in the pathogenesis of DKD; specifically, PRR promoted tubular epithelial cell pyroptosis via DPP4 mediated signaling, highlighting that PRR could be a promising therapeutic target in DKD.

Wnt5a: A promising therapeutic target for inflammation, especially rheumatoid arthritis

BACKGROUND

Wnt5a is a member of the Wnt protein family, which acts on classical or multiple non-classical Wnt signaling pathways by binding to different receptors. The expression regulation and signal transduction of Wnt5a is closely related to the inflammatory response. Abnormal activation of Wnt5a signaling is an important part of inflammation and rheumatoid arthritis (RA).

OBJECTIVES

This paper mainly focuses on Wnt5a protein and its mediated signaling pathway, summarizes the latest research progress of Wnt5a in the pathological process of inflammation and RA, and looks forward to the main directions of Wnt5a in RA research, aiming to provide a theoretical basis for the prevention and treatment of RA diseases by targeting Wnt5a.

RESULTS

Wnt5a is highly expressed in activated blood vessels, histocytes and synoviocytes in inflammatory diseases such as sepsis, sepsis, atherosclerosis and rheumatoid arthritis. It mediates the production of pro-inflammatory cytokines and chemokines, regulates the migration and recruitment of various immune effector cells, and thus participates in the inflammatory response. Wnt5a plays a pathological role in synovial inflammation and bone destruction of RA, and may be an important clinical therapeutic target for RA.

CONCLUSION

Wnt5a is involved in the pathological process of inflammation and interacts with inflammatory factors. Wnt5a may be a new target for regulating the progression of RA disease and intervening therapy because of its multi-modal effects on the etiology of RA, especially as a regulator of osteoclast activity and inflammation.

Applicability of mesenchymal stem cell-derived exosomes as a cell-free miRNA therapy and epigenetic modifiers for diabetes

Given that exosome nanovesicles constitute various growth factors, miRNAs and lncRNAs, they have implications for epigenetic modifications. Few studies have shown that exosomes from mesenchymal stem cells (MSCs) exhibit therapeutic effects on diabetic complications by substituting miRNAs and regulating histone modifications. Therefore, reversing epigenetic aberrations in diabetes may provide new insight into its treatment. This review discusses the impact of DNA and histone methylations on the development of diabetes and its complications. Further, we talk about miRNAs dysregulated in diabetic conditions and the possibility of utilizing mesenchymal stem cell (MSC) exosomes for the development of miRNA cell-free therapy and epigenetic modifiers in reversing diabetic-induced epigenetic alterations.

The O-glycosylating enzyme GALNT2 acts as an oncogenic driver in non-small cell lung cancer

BACKGROUND

N-Acetylgalactosaminyltransferases (GALNTs), the enzymes that initiate mucin-type O-glycosylation, are closely associated with tumor occurrence and progression. However, a comprehensive analysis of GALNTs in non-small cell lung cancer (NSCLC) is lacking.

METHODS

The expression profiles and prognostic values of the GALNT family members in NSCLC were analyzed using publicly available databases. Gain- and loss-of-function experiments were applied to assess the biological function of GALNT2 in NSCLC. High-throughput sequencing and bioinformatics approaches were employed to uncover the regulatory mechanism of GALNT2.

RESULTS

Among the family members of GALNTs, only GALNT2 was frequently overexpressed in NSCLC tissues and was positively correlated with poor prognosis. In vitro assays showed that GALNT2 knockdown repressed NSCLC cell proliferation, migration, and invasion, but induced apoptosis and cell cycle arrest. Correspondently, GALNT2 overexpression exerted the opposite effects. In vivo experiments demonstrated that knockdown of GALNT2 restrained tumor formation in nude mice. Mechanistic investigations revealed that GALNT2 modified the O-glycosylation of ITGA5 and affected the activation of the PI3K/Akt and MAPK/ERK pathways. Further studies showed that miR-30d was a negative regulator of GALNT2.

CONCLUSIONS

These findings suggest that GALNT2 is an oncogene in NSCLC and has the potential as a target for NSCLC therapy.

Targeting epigenetic regulators for treating diabetic nephropathy

Diabetes is accompanied by the worsening of kidney functions. The reasons for kidney dysfunction mainly include high blood pressure (BP), high blood sugar levels, and genetic makeup. Vascular complications are the leading cause of the end-stage renal disorder (ESRD) and death of diabetic patients. Epigenetics has emerged as a new area to explain the inheritance of non-mendelian conditions like diabetic kidney diseases. Aberrant post-translational histone modifications (PTHMs), DNA methylation (DNAme), and miRNA constitute major epigenetic mechanisms that progress diabetic nephropathy (DN). Increased blood sugar levels alter PTHMs, DNAme, and miRNA in kidney cells results in aberrant gene expression that causes fibrosis, accumulation of extracellular matrix (ECM), increase in reactive oxygen species (ROS), and renal injuries. Histone acetylation (HAc) and histone deacetylation (HDAC) are the most studied epigenetic modifications with implications in the occurrence of kidney disorders. miRNAs induced by hyperglycemia in renal cells are also responsible for ECM accumulation and dysfunction of the glomerulus. In this review, we highlight the role of epigenetic modifications in DN progression and current strategies employed to ameliorate DN.

WTAP-mediated N6-methyladenosine modification of NLRP3 mRNA in kidney injury of diabetic nephropathy

Background

Diabetic nephropathy (DN) is prevalent in patients with diabetes. N⁶-methyladenosine (m⁶A) methylation has been found to cause modification of nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing (NLRP) 3, which is involved in cell pyroptosis and inflammation. WTAP is a key gene in modulating NLRP3 m⁶A.

Methods

In this study, WTAP was silenced or overexpressed in high glucose (HG)-treated HK-2 cells to determine its influence on pyroptosis, NLRP3 inflammasome-related proteins, and the release of pro-inflammatory cytokines. NLRP3 expression and m⁶A levels were assessed in the presence of WTAP shRNA (shWTAP). WTAP expression in HK-2 cells was examined with the introduction of C646, a histone acetyltransferase p300 inhibitor.

Results

We found that WTAP expression was enhanced in patients with DN and in HG-treated HK-2 cells. Knockdown of WTAP attenuated HG-induced cell pyroptosis and NLRP3-related pro-inflammatory cytokines in both HK-2 cells and db/db mice, whereas WTAP overexpression promoted these cellular processes in HK-2 cells. WTAP mediated the m⁶A of NLRP3 mRNA that was stabilized by insulin-like growth factor 2 mRNA binding protein 1. Histone acetyltransferase p300 regulated WTAP expression. WTAP mRNA levels were positively correlated with NLRP3 inflammasome components and pro-inflammatory cytokines.

Conclusion

Taken together, WTAP promotes the m⁶A methylation of NLRP3 mRNA to upregulate NLRP3 inflammasome activation, which further induces cell pyroptosis and inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00350-8.