Polygala fallax Hemsl combined with compound Sanqi granules relieves glomerulonephritis by regulating proliferation and apoptosis of glomerular mesangial cells

Inhibition of METTL3 promotes mesangial cell mitophagy and attenuates glomerular damage by alleviating FOSL1 m6A modifications via IGF2BP2-dependent mechanisms

Epigenetic changes are involved in many physiological and pathological processes. Mitophagy plays a critical role in chronic kidney disease (CKD); however, the role of N6-methyladenosine (m6A) modification in renal mitophagy remains unclear. In this research, we aim to elucidate the role of RNA methylation in modulating mitophagy and its involvement in the pathophysiology of chronic glomerulonephritis (CGN). We found that Methyltransferase-like 3 (METTL3) was significantly upregulated in biopsies from CKD patients, as well as in CGN mice and cultured mouse mesangial cells (MMCs), and was inversely correlated with glomerular filtration rate. Adeno-associated virus serotype 9 (AAV9)-mediated METTL3 silencing from mouse kidneys attenuated adenine-induced glomerular damage, and promoted renal mitophagy. METTL3 knockdown significantly reduced the oxidative stress and inflammation levels and promoted mitophagy in lipopolysaccharide (LPS)-stimulated MMCs, while its overexpression significantly aggravated these responses in vitro. Moreover, FOSL1 (Fos-like antigen 1) was identified as a target of METTL3 and the stability of FOSL1 was increased through binding of IGF2BP2 (Insulin-like Growth Factor 2 mRNA-binding Protein 2) to its m6A-modified regions. The mitophagy regulatory effects of FOSL1 were then explored both in vitro and in vivo. Mechanistically, METTL3 modulated AMPK (AMP-activated Protein Kinase)/mTOR (Mechanistic Target of Rapamycin) signaling via the m6A modification of FOSL1 in an IGF2BP2-dependent manner and exerted a mitophagy inhibitory effect. In summary, this study suggested that METTL3-mediated m6A modification is an important mechanism of mesangial cell (MCs) injury in CGN. Targeting m6A through the writer enzyme METTL3 is a potential approach for the treatment of CGN.

Therapeutic effects and mechanisms of alcohol extracts from Polygala fallax Hemsl on endometriosis in rats

Endometriosis is a chronic estrogen-dependent inflammatory disease that significantly affects women's health. Polygala fallax Hemsl. (PFH), a traditional Zhuang medicine, has been frequently used for gynecological disorders. This study investigated the therapeutic effects and mechanisms of the alcohol extract of Polygala fallax Hemsl. (ae-PFH) in a rat model of endometriosis, as well as its potential for combination therapy. SD rats were divided into seven groups: control, model, PFH, mifepristone, PFH combined with mifepristone, exosomes, and PFH combined with exosomes. After 21 days of treatment, body weight, organ coefficients, and histopathological changes in uterine and ovarian tissues were analyzed. UPLC-Q-Exactive Orbitrap-MS identified active components in ae-PFH and serum samples, followed by molecular docking with key disease target proteins. Serum levels of inflammatory cytokines and hormones were measured using ELISA, while protein and mRNA expression of key regulatory factors were assessed via Western blot and q-PCR. Ae-PFH reduced lesion size and suppressed inflammation, angiogenesis, and pain by inhibitied the PI3K/AKT pathway. Additionally, in combination therapy, ae-PFH significantly enhanced therapeutic effects of mifepristone or exosomes derived from umbilical cord mesenchymal stem cells. These findings indicated that ae-PFH presentd a promising medical method for the treatment of endometriosis, exhibiting innovative potentiality for combination therapy.

Polygala fallax Hemsl. ameliorated high glucose-induced podocyte injury by modulating mitochondrial mPTP opening through the SIRT1/PGC-1α pathway

This study aimed to investigate the effects and molecular mechanism of PF on high glucose (HG)-induced podocyte injury. Results found that PF increased proliferation activity, decreased apoptosis, LDH, and caspase-3 levels, and increased nephrin and podocin expression in HG-induced cells. Similarly, PF improved HG-induced mitochondrial damage, decreased Ca2+ and ROS content, alleviated oxidative stress, inhibited mPTP opening, increased mitochondrial membrane potential, and decreased the expressions of Drp1, Bak, Bax, and Cytc in cytoplasm, increased the expressions of SIRT1, PGC-1α, HSP70, HK2, and Cytc in mitochondria of podocytes. The use of mPTP agonist/blocker and SIRT1 inhibitor confirmed that PF alleviates HG-induced podocyte injury by regulating mitochondrial mPTP opening through SIRT1/PGC-1α. In addition, PF affected HK2-VDAC1 protein binding to regulate mPTP opening via the SIRT1/PGC-1α pathway. In conclusion, PF-regulated HK2-VDAC1 protein binding affected mitochondrial mPTP opening and improved HG-induced podocyte injury through the SIRT1/PGC-1α pathway.

Inhibition of ALKBH5 inhibits inflammation and excessive proliferation by promoting TRIM13 m6A modifications in glomerular mesangial cells

Chronic glomerulonephritis (CGN) refers to the inflammation of glomeruli in the kidneys. Glomerular mesangial cells (GMCs) play a pivotal role in the development of CGN. In the present study, we investigated the impact of ALKBH5, a m6A demethylase, on inflammation and hyperproliferation in mouse glomerular mesangial cells (MMCs) and elucidated the molecular mechanisms contributing to CGN. Western blotting and reverse transcriptase-polymerase chain reaction (RT-qPCR) were employed to evaluate the expression of ALKBH5 and TRIM13. In addition, enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of inflammatory factors (IL-1β, TNF-α, and IL-10) in the lipopolysaccharide (LPS)-induced MMCs supernatant. Methylated RNA immunoprecipitation (MeRIP) was performed to investigate the effect of ALKBH5 on the levels of TRIM13-m6A mRNA. The stability of TRIM13 mRNA was evaluated using an actinomycin D assay. Significantly elevated expression of ALKBH5 was found in LPS-induced MMCs. Interference with ALKBH5 expression inhibited inflammation and excessive proliferation in LPS-induced MMCs. Moreover, interfering with ALKBH5 expression significantly reduced the levels of TRIM13-m6A modification. The overexpression of TRIM13 in MMCs reversed the inflammation and proliferation induced by ALKBH5 interference. In addition, interference with TRIM13 expression inhibited the activation of the NF-κB pathway and suppressed inflammation and proliferation in MMCs. Inhibiting ALKBH5 hinders inflammation and hyperproliferation by improving TRIM13-m6A modification in glomerular MCs. We believe these findings will further provide insights into the molecular mechanisms and potential therapeutic targets for CGN.

Construction of chronic glomerulonephritis‑related lncRNA‑mRNA regulatory network and lncRNA‑-miRNA‑mRNA ceRNA network by bioinformatics analysis

Long non-coding RNAs (lncRNAs) are ncRNA transcripts >200 nucleotides that are important genetic regulators. LncRNAs can directly regulate mRNA through a lncRNA-mRNA regulatory mode and can also regulate mRNA through competitive binding to micro (mi)RNA, which is generally known as the competitive endogenous RNA (ceRNA) network. The present study evaluated the functional roles and regulatory networks of lncRNAs in chronic glomerulonephritis (CGN). The proliferative ability of mouse glomerular mesangial cells (GMCs) induced by different concentrations of lipopolysaccharide (LPS) was assessed using the Cell Counting Kit-8 assay, and RNA sequencing (RNA-seq) was performed to identify differentially expressed lncRNAs in LPS-induced GMCs. Based on the sequencing results, six lncRNAs were selected for validation using reverse transcription-quantitative PCR (RT-qPCR). Furthermore, the lncRNA-mRNA regulatory network and the lncRNA-miRNA-mRNA ceRNA network were constructed to assess the role and mechanism of CGN-related lncRNAs. To elucidate the biological functions of lncRNAs, Gene Ontology (GO) biological process term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed on all mRNAs involved in the lncRNA-mRNA regulatory network and in the ceRNA network. A total of 1,532 differentially expressed lncRNAs, including 594 upregulated lncRNAs and 938 downregulated lncRNAs, were identified using RNA-seq. The results of RT-qPCR validation were consistent with RNA-seq results. An lncRNA-mRNA regulatory network, including 236 lncRNAs and 556 mRNAs, and a ceRNA network, including 6 lncRNAs, 18 miRNAs and 419 mRNAs, were successfully constructed. The GO biological process term enrichment and KEGG pathway enrichment analyses demonstrated that those lncRNAs were often related to inflammatory response and substance metabolism. The present study identified key CGN-related lncRNAs in LPS-induced GMCs, and further demonstrated a global view of the lncRNA-mRNA regulatory network and ceRNA network involved in CGN. These results offered novel insights into the roles of lncRNAs in the pathogenesis of CGN and identified potential diagnostic biomarkers.

The potential role of N6-methyladenosine modification of LncRNAs in contributing to the pathogenesis of chronic glomerulonephritis

BACKGROUND

Increasing evidence indicates that N6-methyladenosine (m6A) modification of mRNAs has been shown to play a critical role in the occurrence and development of many diseases, while little is known about m6A modification in long non-coding RNAs (LncRNAs). Our study aims to investigate the potential functions of LncRNA m6A modifications in lipopolysaccharide (LPS)-induced mouse mesangial cells (MMCs), providing us with a new perspective on the molecular mechanisms of chronic glomerulonephritis (CGN) pathogenesis.

METHODS

Differentially methylated LncRNAs were identified by Methylated RNA immunoprecipitation sequencing (MeRIP-seq). LncRNA-mRNA and LncRNA-associated LncRNA-miRNA-mRNA (CeRNA) networks were constructed by bioinformatics analysis. Furthermore, we utilized gene ontology (GO) and pathway enrichment analyses (KEGG) to explore target genes from co-expression networks. In addition, the total level of m6A RNA methylation and expression of methyltransferase and pro-inflammatory cytokines were detected by the colorimetric quantification method and western blot, respectively. Cell viability and cell cycle stage were detected by cell counting kit-8 (CCK-8) and flow cytometry.

RESULTS

In total, 1141 differentially m6A-methylated LncRNAs, including 529 hypermethylated LncRNAs and 612 hypomethylated LncRNAs, were determined by MeRIP-seq. The results of GO and KEGG analysis revealed that the target mRNAs were mainly enriched in signal pathways, such as the NF-kappa B signaling pathway, MAPK signaling pathway, Toll-like receptor signaling pathway, and apoptosis signaling pathway. In addition, higher METTL3 expression was found in CGN kidney tissues using the GEO database. METTL3 knockdown in MMC cells drastically reduced the levels of m6A RNA methylation, pro-inflammatory cytokines IL6 and TNF-α, and inhibited cell proliferation and cycle progression.

CONCLUSIONS

Our findings provide a basis and novel insight for further investigations of m6A modifications in LncRNAs for the pathogenesis of CGN.

Natural Bioactive Compounds Targeting NADPH Oxidase Pathway in Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, in both developed and developing countries. According to the WHO report, the morbidity and mortality caused by CVD will continue to rise with the estimation of death going up to 22.2 million in 2030. NADPH oxidase (NOX)-derived reactive oxygen species (ROS) production induces endothelial nitric oxide synthase (eNOS) uncoupling and mitochondrial dysfunction, resulting in sustained oxidative stress and the development of cardiovascular diseases. Seven distinct members of the family have been identified of which four (namely, NOX1, 2, 4 and 5) may have cardiovascular functions. Currently, the treatment and management plan for patients with CVDs mainly depends on the drugs. However, prolonged use of prescribed drugs may cause adverse drug reactions. Therefore, it is crucial to find alternative treatment options with lesser adverse effects. Natural products have been gaining interest as complementary therapy for CVDs over the past decade due to their wide range of medicinal properties, including antioxidants. These might be due to their potent active ingredients, such as flavonoid and phenolic compounds. Numerous natural compounds have been demonstrated to have advantageous effects on cardiovascular disease via NADPH cascade. This review highlights the potential of natural products targeting NOX-derived ROS generation in treating CVDs. Emphasis is put on the activation of the oxidases, including upstream or downstream signalling events.

The extract of Polygala fallax Hemsl. slows the progression of diabetic nephropathy by targeting TLR4 anti-inflammation and MMP-2/9-mediated anti-fibrosis in vitro

BACKGROUND

Polygala fallax Hemsl. is a plant that is commonly used as a folk medicine by Guangxi ethnic minorities, and it is also widely used in the clinical treatment of chronic diseases in China. The extract of P. fallax (EPF) contains key biologically active components from the roots and stems. However, the role of P. fallax or EPF in diabetic nephropathy (DN) is unclear.

PURPOSE

This study aimed to investigate the effects and mechanisms of EPF on high glucose (HG)-induced human glomerular mesangial cell (HMC) injury, inflammation, fibrosis, and apoptosis in vitro.

METHODS

For the in vitro study, MTT and ELISA assays were performed with HG-treated HMCs, as well as MMP, Hoechst, flow cytometry, qRT-PCR, and western blot analyses. The expression of the TLR4/NF-κB pathway, along with its downstream inflammatory, apoptosis, and fibrosis factors, was measured. The expression of the TLR4/NF-κB pathway and its downstream inflammatory factors were also measured after the addition of TLR4 inhibitors.

RESULTS

Our results suggest that EPF can reverse the hyperproliferation and apoptosis of HMCs induced by HG. In addition, the extract inhibited the increase in inflammatory factors IL-6, TNF-α, IL-1β, MCP-1, and IL-18 in cells treated with HG. The mRNA and protein expression of TLR4, MyD88, NF-κB, Col IV, FN, MMP-9, and MMP-2 were downregulated by EPF. In addition, EPF significantly reduced the loss of MMP and the upregulation of Bcl-2/Bax mRNA and protein levels after HG treatment.

CONCLUSION

These results demonstrated that EPF protects against diabetes-induced renal injury in vitro. EPF protected against HG-induced HMCs proliferation, apoptosis, fibrosis, and inflammation likely via inhibition of TLR4-dependent NF-κB signaling. This herbal extract may also be a novel treatment for DN.