Long noncoding RNA lnc-TSI inhibits renal fibrogenesis by negatively regulating the TGF-β/Smad3 pathway

Role of epigenetically regulated inflammation in renal diseases

In recent decades, renal disease research has witnessed remarkable advances. Experimental evidence in this field has highlighted the role of inflammation in kidney disease. Epigenetic dynamics and immunometabolic reprogramming underlie the alterations in cellular responses to intrinsic and extrinsic stimuli; these factors determine cell identity and cell fate decisions and represent current research hotspots. This review focuses on recent findings and emerging concepts in epigenetics and inflammatory regulation and their effect on renal diseases. This review aims to summarize the role and mechanisms of different epigenetic modifications in renal inflammation and injury and provide new avenues for future research on inflammation-related renal disease and drug development.

Therapeutic potential for renal fibrosis by targeting Smad3-dependent noncoding RNAs

Renal fibrosis is a characteristic hallmark of chronic kidney disease (CKD) that ultimately results in renal failure, leaving patients with few therapeutic options. TGF-β is a master regulator of renal fibrosis and mediates progressive renal fibrosis via both canonical and noncanonical signaling pathways. In the canonical Smad signaling, Smad3 is a key mediator in tissue fibrosis and mediates renal fibrosis via a number of noncoding RNAs (ncRNAs). In this regard, targeting Smad3-dependent ncRNAs may offer a specific therapy for renal fibrosis. This review highlights the significance and innovation of TGF-β/Smad3-associated ncRNAs as biomarkers and therapeutic targets in renal fibrogenesis. In addition, the underlying mechanisms of these ncRNAs and their future perspectives in the treatment of renal fibrosis are discussed.

HIF-1α: A potential therapeutic opportunity in renal fibrosis

Renal fibrosis is a common outcome of various renal injuries, leading to structural destruction and functional decline of the kidney, and is also a critical prognostic indicator and determinant in renal diseases therapy. Hypoxia is induced in different stress and injuries in kidney, and the hypoxia inducible factors (HIFs) are activated in the context of hypoxia in response and regulation the hypoxia in time. Under stress and hypoxia conditions, HIF-1α increases rapidly and regulates intracellular energy metabolism, cell proliferation, apoptosis, and inflammation. Through reprogramming cellular metabolism, HIF-1α can directly or indirectly induce abnormal accumulation of metabolites, changes in cellular epigenetic modifications, and activation of fibrotic signals. HIF-1α protein expression and activity are regulated by various posttranslational modifications. The drugs targeting HIF-1α can regulate the downstream cascade signals by inhibiting HIF-1α activity or promoting its degradation. As the renal fibrosis is affected by renal diseases, different diseases may trigger different mechanisms which will affect the therapy effect. Therefore, comprehensive analysis of the role and contribution of HIF-1α in occurrence and progression of renal fibrosis, and determination the appropriate intervention time of HIF-1α in the process of renal fibrosis are important ideas to explore effective treatment strategies. This study reviews the regulation of HIF-1α and its mediated complex cascade reactions in renal fibrosis, and lists some drugs targeting HIF-1α that used in preclinical studies, to provide new insight for the study of the renal fibrosis mechanism.

Deciphering roles of protein post-translational modifications in IgA nephropathy progression and potential therapy

Immunoglobulin A nephropathy (IgAN), one type of glomerulonephritis, displays the accumulation of glycosylated IgA in the mesangium. Studies have demonstrated that both genetics and epigenetics play a pivotal role in the occurrence and progression of IgAN. Post-translational modification (PTM) has been revealed to critically participate in IgAN development and progression because PTM dysregulation results in impaired degradation of proteins that regulate IgAN pathogenesis. A growing number of studies identify that PTMs, including sialylation, o-glycosylation, galactosylation, phosphorylation, ubiquitination and deubiquitination, modulate the initiation and progression of IgAN. Hence, in this review, we discuss the functions and mechanisms of PTMs in regulation of IgAN. Moreover, we outline numerous compounds that govern PTMs and attenuate IgAN progression. Targeting PTMs might be a useful strategy to ameliorate IgAN.

Regulatory networks of circRNA- centred ceRNAs in sepsis-induced acute kidney injury

Sepsis is the primary cause of acute kidney injury (AKI) and is associated with high mortality rates. Growing evidence suggests that noncoding RNAs are vitally involved in kidney illnesses, whereas the role of circular RNAs (circRNAs) in sepsis-induced AKI (SAKI) remains largely unknown. In this present study, caecal ligation and puncture (CLP) in mice was performed to establish an SAKI model. The expression of circRNAs and mRNAs was analysed using circRNA microarray or next-generation sequencing. The results revealed that the expressions of 197 circRNAs and 2509 mRNAs were dysregulated. Validation of the selected circRNAs was performed by qRT-PCR. Bioinformatics analyses and chromatin immunoprecipitation demonstrated that NF-κB/p65 signalling induced the upregulation of circC3, circZbtb16, and circFkbp5 and their linear counterparts by p65 transcription in mouse tubular epithelial cells (mTECs). Furthermore, competitive endogenous RNA (ceRNA) networks demonstrated that some components of NF-κB signalling were potential targets of these dysregulated circRNAs. Among them, Tnf-α was increased by circFkbp5 through the downregulation of miR-760-3p in lipopolysaccharide (LPS)-stimulated mTECs. Knocking down circFkbp5 inhibited the p65 phosphorylation and apoptosis in injured mTECs. These findings suggest that the selected circRNAs and the related ceRNA networks provide new knowledge into the fundamental mechanism of SAKI and circFkbp5/miR-760-3p/Tnf-α axis might be therapeutic targets.

Flavokawain A ameliorates pulmonary fibrosis by inhibiting the TGF-β signaling pathway and CXCL12/CXCR4 axis

Idiopathic pulmonary fibrosis is a progressive fibrotic lung disease characterized by myofibroblast proliferation and extracellular matrix deposition that has a high mortality rate and limited therapeutic options. Flavokawain A(FKA) is the major component of chalcone in kava extract. FKA has been reported to inhibit TGF-β1-induced cardiomyocyte fibrosis by suppressing ROS production in A7r5 cells, but the role and mechanism of FKA in pulmonary fibrosis are unknown. In this study, we evaluated the effect of FKA on pulmonary fibrosis using an animal model of bleomycin-induced pulmonary fibrosis and showed that FKA alleviated the development of pulmonary fibrosis in a dose-dependent manner and improved lung function as well as collagen deposition and extracellular matrix accumulation in mice. In vitro studies showed that FKA inhibited myofibroblast activation and lung fibrosis progression by inhibiting TGF-β1/Smad signaling in a dose-dependent manner. In addition, we identified CXCL12 as a potential target of FKA through target prediction. Molecular docking, CETSA(cellular thermal displacement assay) and silver staining assays further demonstrated that FKA could interact with CXCL12 and that FKA could inhibit CXCL12 dimerization in vitro. Further analysis revealed that FKA could inhibit fibroblast activation and reduce extracellular matrix (ECM) production and collagen deposition by blocking CXCL12/CXCR4 signaling, and knocking down CXCR4 expression could weaken the inhibitory effect of FKA on CXCL12/CXCR4 signal transduction. In conclusion, our study showed that FKA inhibited CXCL12/CXCR4 signaling by inhibiting CXCL12 dimerization, blocked the CXCL12/CXCR4 signaling pathway and inhibited the TGF-β1-mediated signaling pathway to ameliorate pulmonary fibrosis, and FKA is a promising therapeutic agent for pulmonary fibrosis.

High-density lipoprotein regulates angiogenesis by long non-coding RNA HDRACA

Normal high-density lipoprotein (nHDL) can induce angiogenesis in healthy individuals. However, HDL from patients with coronary artery disease undergoes various modifications, becomes dysfunctional (dHDL), and loses its ability to promote angiogenesis. Here, we identified a long non-coding RNA, HDRACA, that is involved in the regulation of angiogenesis by HDL. In this study, we showed that nHDL downregulates the expression of HDRACA in endothelial cells by activating WW domain-containing E3 ubiquitin protein ligase 2, which catalyzes the ubiquitination and subsequent degradation of its transcription factor, Kruppel-like factor 5, via sphingosine 1-phosphate (S1P) receptor 1. In contrast, dHDL with lower levels of S1P than nHDL were much less effective in decreasing the expression of HDRACA. HDRACA was able to bind to Ras-interacting protein 1 (RAIN) to hinder the interaction between RAIN and vigilin, which led to an increase in the binding between the vigilin protein and proliferating cell nuclear antigen (PCNA) mRNA, resulting in a decrease in the expression of PCNA and inhibition of angiogenesis. The expression of human HDRACA in a hindlimb ischemia mouse model inhibited the recovery of angiogenesis. Taken together, these findings suggest that HDRACA is involved in the HDL regulation of angiogenesis, which nHDL inhibits the expression of HDRACA to induce angiogenesis, and that dHDL is much less effective in inhibiting HDRACA expression, which provides an explanation for the decreased ability of dHDL to stimulate angiogenesis.

Long noncoding RNA AI662270 promotes kidney fibrosis through enhancing METTL3-mediated m6 A modification of CTGF mRNA

The sustained release of profibrotic cytokines, mainly transforming growth factor-β (TGF-β), leads to the occurrence of kidney fibrosis and chronic kidney disease (CKD). Connective tissue growth factor (CTGF) appears to be an alternative target to TGF-β for antifibrotic therapy in CKD. In this study, we found that long noncoding RNA AI662270 was significantly increased in various renal fibrosis models. In vivo, ectopic expression of AI662270 alone was sufficient to activate interstitial fibroblasts and drive kidney fibrosis, whereas inhibition of AI662270 blocked the activation of interstitial fibroblasts and ameliorated kidney fibrosis in various murine models. Mechanistic studies revealed that overexpression of AI662270 significantly increased CTGF product, which was required for the role of AI662270 in driving kidney fibrosis. Furthermore, AI662270 binds to the CTGF promoter and directly interacts with METTL3, the methyltransferase of RNA N6 -methyladenosine (m6 A) modification. Functionally, AI662270-mediated recruitment of METTL3 increased the m6 A methylation of CTGF mRNA and consequently enhanced CTGF mRNA stability. In conclusion, our results support that AI662270 promotes CTGF expression at the posttranscriptional stage by recruiting METTL3 to the CTGF promoter and depositing m6 A modifications on the nascent mRNA, thereby, uncovering a novel regulatory mechanism of CTGF in the pathogenesis of kidney fibrosis.

The lncRNA LETS1 promotes TGF-β-induced EMT and cancer cell migration by transcriptionally activating a TβR1-stabilizing mechanism

Transforming growth factor-β (TGF-β) signaling is a critical driver of epithelial-to-mesenchymal transition (EMT) and cancer progression. In SMAD-dependent TGF-β signaling, activation of the TGF-β receptor complex stimulates the phosphorylation of the intracellular receptor-associated SMADs (SMAD2 and SMAD3), which translocate to the nucleus to promote target gene expression. SMAD7 inhibits signaling through the pathway by promoting the polyubiquitination of the TGF-β type I receptor (TβRI). We identified an unannotated nuclear long noncoding RNA (lncRNA) that we designated LETS1 (lncRNA enforcing TGF-β signaling 1) that was not only increased but also perpetuated by TGF-β signaling. Loss of LETS1 attenuated TGF-β-induced EMT and migration in breast and lung cancer cells in vitro and extravasation of the cells in a zebrafish xenograft model. LETS1 potentiated TGF-β-SMAD signaling by stabilizing cell surface TβRI, thereby forming a positive feedback loop. Specifically, LETS1 inhibited TβRI polyubiquitination by binding to nuclear factor of activated T cells (NFAT5) and inducing the expression of the gene encoding the orphan nuclear receptor 4A1 (NR4A1), a component of a destruction complex for SMAD7. Overall, our findings characterize LETS1 as an EMT-promoting lncRNA that potentiates signaling through TGF-β receptor complexes.

Effects and mechanisms of Chinese herbal medicine on IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN), is the main cause of end-stage renal disease, that causes serious physical and psychological burden to patients worldwide. Some traditional treatment measures, such as blocking the renin-angiotensin-aldosterone system, controlling blood pressure, and following a low-protein diet, may not achieve satisfactory results. Therefore, more effective and safe therapies for IgAN are urgently needed.

PURPOSE

The aim of this review is to summarize the clinical efficacy of Chinese herbal medicines (CHMs) and their active ingredients in the treatment and management of IgAN based on the results of clinical trials, systematic reviews, and meta-analyses, to fully understand the advantages and perspectives of CHMs in the treatment of IgAN.

STUDY DESIGN AND METHODS

For this review, the following electronic databases were consulted: PubMed, ResearchGate, Science Direct, Web of Science, Chinese National Knowledge Infrastructure and Wanfang Data, "IgA nephropathy," "traditional Chinese medicine," "Chinese herbal medicine," "herb," "mechanism," "Meta-analysis," "systematic review," "RCT" and their combinations were the keywords to search the relevant literature. Data were collected from 1990 to 2022.

RESULTS

This review found that the active ingredients of CHMs commonly act on multiple signaling pathways in the clinical treatment of IgAN, mainly with antioxidant, anti-inflammatory and anti-fibrosis effects, and regulation of autophagy.

CONCLUSION

Compared with the single-target therapy of modern medicine, CHMs can regulate the corresponding pathways from the aspects of anti-inflammation, anti-oxidation, anti-fibrosis and autophagy to play a multi-target treatment of IgAN through syndrome differentiation and treatment, which has good clinical efficacy and can be used as the first choice or alternative therapy for IgAN treatment. This review provides evidence and research direction for a comprehensive clinical understanding of the protective effect of Chinese herbal medicine on IgAN.

Long non-coding RNA PVT1 regulates atherosclerosis progression via the microRNA-106b-5p/ACSL4 axis

Long non-coding RNAs (lncRNAs) have been associated with atherosclerosis (AS), but the role of lncRNA PVT1 in this disease is still unknown. However, lncRNA PVT1 was found to be significantly upregulated in the serum of AS patients. In vitro experiments using human vascular endothelial cells (HUVECs) showed that oxidized low-density lipoprotein (ox-LDL) treatment enhanced PVT1 expression and impeded HUVEC proliferation, which could be reversed by PVT1 knockdown or miR-106b-5p mimics. Additionally, knockdown of PVT1 and overexpression of miR-106b-5p inhibited the increase of iron content, MDA level, lipid ROS, ACSL4, and PTGS2 in ox-LDL-induced HUVECs, as well as the decrease of GSH and GPX4. We also found that PVT1 knockdown reduced lipid deposition, atherosclerotic plaque number, and size in ApoE^-/- mice. These results suggest that PVT1 plays a crucial role in AS progression by regulating the miR-106b-5p/ACSL4 axis in HUVECs, and may therefore be a potential therapeutic target for AS.

Jiedu Tongluo Baoshen formula enhances renal tubular epithelial cell autophagy to prevent renal fibrosis by activating SIRT1/LKB1/AMPK pathway

Renal fibrosis, an important pathological change in the development of diabetic kidney disease (DKD), urgently needs new treatment methods clinically. The Jiedu Tongluo Baoshen (JTBF) formula was created based on the theory of toxic damage to the kidney collaterals, and a variety of active ingredients in JTBF have inhibitory effects on epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM). In this study, the Ultra Performance Liquid Chromatography (UPLC) was employed to analyze the effective ingredients in the JTBF formula. After screening in the PubChem database, we identified 94 active compounds of JTBF and predicted the SIRT1 pathway as potential targets through network pharmacology. In addition, in the high fat diet (HFD)+Streptozocin (STZ)-induced DKD rat model and high glucose (HG)-induced NRK-52E cell model, JTBF treatment activates the phosphorylation of LKB1 and AMPK and enhances the autophagy activity of NRK-52E cells, thereby reducing the accumulation of EMT and ECM. These results have been confirmed in vivo and in vitro experiments. JTBF enhances the autophagy activity of renal tubular epithelial cells and inhibits the progression of DKD renal fibrosis by activating the SIRT1/LKB1/AMPK signal pathway. This study provides new insights into the molecular mechanism of JTBF to prevent and treat DKD renal fibrosis.

Myostatin silencing inhibits podocyte apoptosis in membranous nephropathy through Smad3/PKA/NOX4 signaling pathway

This article focuses on deciphering the effect of myostatin (MSTN) on podocyte apoptosis in membranous nephropathy (MN) and fathoming out its underlying mechanism. Rats received the intravenous injection of cationized-bovine serum albumin to induce MN in vivo, while angiotensin II (Ang II) was exposed to AB8/13 cells to induce MN model in vitro. The mRNA expression of MSTN was detected by qRT-PCR. The effects of MSTN silencing on MN model rats and cells were assessed by cell counting kit-8 assay, flow cytometry, hematoxylin and eosin staining, and TUNEL assay. The expressions of proteins related to apoptosis and Smad3/protein kinase A (PKA)/NADPH oxidase 4 (NOX4) signaling pathway were examined by western blot. As a result, MSTN was highly expressed in MN cell and rat models. Besides, knockdown of MSTN elevated the MN cell viability and dwindled apoptosis rate, as well as attenuated kidney injury in MN rats. Meanwhile, MSTN silencing lessened the expressions of phosphorylated (p)-Smad3 and Nox4, while boosting the p-PKA expression in MN rats and cells. Additionally, Smad3 overexpression reversed the above effects of MSTN silencing on Ang II-induced podocytes. In conclusion, MSTN knockdown restrains the podocyte apoptosis through regulating Smad3/PKA/NOX4 signaling pathway.

Long noncoding RNA ENST00000436340 promotes podocyte injury in diabetic kidney disease by facilitating the association of PTBP1 with RAB3B

Dysfunction of podocytes has been regarded as an important early pathologic characteristic of diabetic kidney disease (DKD), but the regulatory role of long noncoding RNAs (lncRNAs) in this process remains largely unknown. Here, we performed RNA sequencing in kidney tissues isolated from DKD patients and nondiabetic renal cancer patients undergoing surgical resection and discovered that the novel lncRNA ENST00000436340 was upregulated in DKD patients and high glucose-induced podocytes, and we showed a significant correlation between ENST00000436340 and kidney injury. Gain- and loss-of-function experiments showed that silencing ENST00000436340 alleviated high glucose-induced podocyte injury and cytoskeleton rearrangement. Mechanistically, we showed that fat mass and obesity- associate gene (FTO)-mediated m6A induced the upregulation of ENST00000436340. ENST00000436340 interacted with polypyrimidine tract binding protein 1 (PTBP1) and augmented PTBP1 binding to RAB3B mRNA, promoted RAB3B mRNA degradation, and thereby caused cytoskeleton rearrangement and inhibition of GLUT4 translocation to the plasma membrane, leading to podocyte injury and DKD progression. Together, our results suggested that upregulation of ENST00000436340 could promote podocyte injury through PTBP1-dependent RAB3B regulation, thus suggesting a novel form of lncRNA-mediated epigenetic regulation of podocytes that contributes to the pathogenesis of DKD.

Anti-angiogenic effect of exo-LncRNA TUG1 in myocardial infarction and modulation by remote ischemic conditioning

The successful use of exosomes in therapy after myocardial infarction depends on an improved understanding of their role in cardiac signaling and regulation. Here, we report that exosomes circulating after myocardial infarction (MI) carry LncRNA TUG1 which downregulates angiogenesis by disablement of the HIF-1α/VEGF-α axis and that this effect can be counterbalanced by remote ischemic conditioning (RIC). Rats with MI induced through left coronary artery ligation without (MI model) and with reperfusion (ischemia/reperfusion I/R model) were randomized to RIC, or MI (I/R) or sham-operated (SO) control. Data from one cohort study and one randomized-controlled trial of humans with MI were also utilized, the former involving patients who had not received percutaneous coronary intervention (PCI) and the latter patients with PCI. Exosome concentrations did not differ between intervention groups (RIC vs. control) in rats (MI and I/R model) as well as humans (with and without PCI). However, MI and I/R exosomes attenuated HIF-1α, VEGF-α, and endothelial function. LncRNA TUG1 was increased in MI and I/R exosomes, but decreased in SO and RIC exosomes. HIF-1α expression was downregulated with MI and I/R exosomes but increased with RIC exosomes. Exosome inhibition suppressed HIF-1α upregulation through RIC exosomes. VEGF-α was identified as HIF-1α-regulated target gene. Knockdown of HIF-1α decreased VEGF-α, endothelial cell capability, and tube formation. Overexpression of HIF-1α exerted opposite effects. Transfection and co-transfection of 293 T cells with exosome-inhibitor GW4869 and HIF-1α inhibitor si-HIF-1α confirmed the exosomal-LncRNA TUG1/HIF-1α/VEGF-α pathway. LncRNA TUG1 is a potential therapeutic target after MI with or without reperfusion through PCI.

TGF-β1 regulates the lncRNA transcriptome of ovarian granulosa cells in a transcription activity-dependent manner

OBJECTIVES

Transforming growth factor β1 (TGF-β1), an essential cytokine belongs to TGF-β superfamily, is crucial for female fertility. Increasing evidence show that long noncoding RNAs (lncRNAs) influence the state of granulosa cells (GCs). This study aimed to detect the effects of TGF-β1 on the lncRNA transcriptome, and investigate whether lncRNAs mediate the functions of TGF-β1 in GCs.

MATERIAL AND METHODS

RNA-seq and bioinformatics analyses were performed to identify and characterize the differentially expressed lncRNAs (DElncRNAs). The regulatory mechanism of TGF-β1 to lncRNA transcriptome was analyzed by chromatin immunoprecipitation. The effects of lncRNAs on the antiapoptotic and proproliferative functions of TGF-β1 were examined by morphological analysis, fluorescence-activated cell sorting, Cell Counting Kit-8, and Western blot.

RESULTS

A total of 72 DElncRNAs highly sensitive to TGF-β1 were identified with the criteria of |log₂ (fold chage)| ≥ 3 and false discovery rate < 0.05. Functional assessment showed that DElncRNAs were enriched in TGF-β, nuclear factor kappa B, p53, and Hippo pathways which are crucial for the normal state and function of GCs. Importantly, SMAD4 is essential for the regulation of TGF-β1 to lncRNA transcriptome. In vitro studies confirmed that TGF-β1 induced TEX14-IT1 transcription in a SMAD4-dependent manner, and TEX14-IT1 mediated the antiapoptotic and proproliferative effects of TGF-β1 in GCs.

CONCLUSIONS

Our findings demonstrate that TGF-β1 alters lncRNA transcriptome in a SMAD4-dependent manner, and highlight that lncRNAs mediate the functions of TGF-β1 in GCs, which contribute to a better understanding of the epigenetic regulation of female fertility.

Zhen Wu decoction represses renal fibrosis by invigorating tubular NRF2 and TFAM to fuel mitochondrial bioenergetics

BACKGROUND

Zhen Wu Decoction (ZWD) is a prescription from the classical text "Treatise on Exogenous Febrile Disease" and has been extensively used to control kidney diseases since the time of the Eastern Han Dynasty.

HYPOTHESIS

We hypothesized that ZWD limits tubular fibrogenesis by reinvigorating tubular bio-energetic capacity.

STUDY DESIGN / METHODS

A mouse model of chronic kidney disease (CKD) was established using unilateral ureteral obstruction (UUO). Three concentrations of ZWD, namely 25.2 g/kg (high dosage), 12.6 g/kg (middle dosage), and 6.3 g/kg (low dosage), were included to study the dose-effect relationship. Real-time qPCR was used to observe gene transcription in blood samples from patients with CKD. Different siRNAs were designed to study the role of mitochondrial transcription factor A (TFAM) and nuclear factor (erythroid-derived 2)-related factor 2 (NRF2) in transforming growth factor (TGF)-β1 induced fibrogenesis and mitochondrial damage.

RESULTS

We showed that ZWD efficiently attenuates renal function impairment and reduces renal interstitial fibrosis. TFAM and NRF2 were repressed, and the stimulator of interferon genes (STING) was activated in CKD patient blood sample. We further confirmed that ZWD activated TFAM depended on NRF2 as an important negative regulator of STING in mouse kidneys. Treatment with ZWD significantly reduced oxidative stress and inflammation by regulating the levels of oxidative phosphorylation (OXPHOS) and pro-inflammatory factors, such as interleukin-6, interleukin-1β, tumor necrosis factor receptor 1, and mitochondrial respiratory chain subunits. NRF2 inhibitors can weaken the ability of ZWD to increase TFAM expression and heal injured mitochondria, playing a similar role to that of STING inhibitors. Our study showed that ZWD elevates the expression of TFAM and mitochondrial respiratory chain subunits by promoting NRF2 activation, after suppressing mitochondrial membrane damage and cristae breakdown and restricting mitochondrial DNA (mtDNA) leakage into the cytoplasm to reduce STING activation.

CONCLUSION

ZWD maintains mitochondrial integrity and improves OXPHOS which represents an innovative insight into "strengthening Yang-Qi" theory. ZWD limits tubular fibrogenesis by reinvigorating tubular bioenergetic capacity.

Long non-coding RNA lnc-CHAF1B-3 promotes renal interstitial fibrosis by regulating EMT-related genes in renal proximal tubular cells

Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-β1 (TGF-β1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-β1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. In situ hybridization demonstrated that lnc-CHAF1B-3 is expressed only in proximal tubules. These findings suggest lnc-CHAF1B-3 affects the progression of RIF by regulating EMT-related signaling. Thus, lnc-CHAF1B-3 is a potential target in the treatment of RIF.

LncRNA ENSMUST00000171502 Induced by HIF-1α Ameliorates Ischemic Acute Kidney Injury via Targeting the miR-130b-3p/Mybl-1 Axis

Background: Numerous studies have suggested that long non-coding RNA (lncRNA) affects the progression of ischemic acute kidney injury (IAKI). However, little information is currently available concerning the mechanisms of lncRNA171502 involved in IAKI. Methods: We applied an RT-qPCR assay for the expression of lncRNA171502 and miRNA-130b-3p, immunoblotting for the detection of Mybl-1-myeloblastosis oncogene-like 1 (Mybl-1) and cleaved caspase-3 (CC3) expression, and flow cytometry (FCM) for the evaluation of apoptosis. Result: Initially, lncRNA171502 was induced by HIF-1α in the mouse proximal tubular (BUMPT) cell line and C57BL/6J mice during ischemic injury. Secondly, ischemic injury-induced BUMPT cell apoptosis was markedly relieved following the overexpression of lncRNA171502. However, this effect was enhanced by the knockdown of lncRNA171502. Mechanistically, lncRNA171502 could sponge miRNA-130b-3p and would subsequently upregulate the expression of Mybl-1 to drive the apoptotic process. Lastly, the overexpression of lncRNA171502 alleviated the development of IAKI by targeting miRNA-130b-3p/Mybl-1 pathways. Conclusions: In summary, the HIF-1α/lncRNA171502/miRNA-130b-3p/Mybl-1 axis prevented the progression of IAKI and might serve as a potential therapeutic target.

A circular RNA, circPTPN14, increases MYC transcription by interacting with FUBP1 and exacerbates renal fibrosis

Fibrosis is a relentlessly progressive and irreversible cause of organ damage, as in chronic kidney disease (CKD), but its underlying mechanisms remain elusive. We found that a circular RNA, circPTPN14, is highly expressed in human kidneys with biopsy-proved chronic interstitial fibrosis, mouse kidneys subjected to ischemia/reperfusion (IR) or unilateral ureteral obstruction (UUO), and TGFβ1-stimulated renal tubule epithelial cells (TECs). The intrarenal injection of circPTPN14 shRNA alleviated the progression of fibrosis in kidneys subjected to IR or UUO. Knockdown of circPTPN14 in TECs inhibited TGFβ1-induced expression of profibrotic genes, whereas overexpressing circPTPN14 increased the profibrotic effect of TGFβ1. The profibrotic action of circPTPN14 was ascribed to an increase in MYC transcription. The binding of circPTPN14 to the KH3 and KH4 domains of far upstream element (FUSE) binding protein 1 (FUBP1) enhanced the interaction between FUBP1 and FUSE domain, which was required for the initiation of MYC transcription. In human kidneys (n = 30) with biopsy-proved chronic interstitial fibrosis, the expression of circPTPN14 positively correlated with MYC expression. Taken together these studies show a novel mechanism in the pathogenesis of renal fibrosis, mediated by circPTPN14, which can be a target in the diagnosis and treatment of CKD.

Novel lncRNA-prader willi/angelman region RNA, SNRPN neighbour (PWARSN) aggravates tubular epithelial cell pyroptosis by regulating TXNIP via dual way in diabetic kidney disease

OBJECTIVES

Elevated thioredoxin-interacting protein (TXNIP)-induced pyroptosis contributes to the pathology of diabetic kidney disease (DKD). However, the molecular mechanisms in dysregulated TXNIP in DKD remain largely unclear.

MATERIALS AND METHODS

Transcriptomic analysis identified a novel long noncoding RNA-Prader Willi/Angelman region RNA, SNRPN neighbour (PWARSN)-which was highly expressed in a proximal tubular epithelial cell (PTEC) under high glucose conditions. We focused on revealing the functions of PWARSN in regulating TXNIP-mediated pyroptosis in PTECs by targeting PWARSN expression via lentivirus-mediated overexpression and CRISPR-Cas9-based knockout in vitro and overexpressing PWARSN in the renal cortex by AAV-9 targeted injection in vivo. A number of molecular techniques disclosed the mechanisms of PWARSN in regulating TXNIP induced-pyroptosis in DKD.

RESULTS

TXNIP-NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and PTEC pyroptosis were activated in the renal tubules of patients with DKD and in diabetic mice. Then we explored that PWARSN enhanced TXNIP-driven PTECs pyroptosis in vitro and in vivo. Mechanistically, cytoplasmic PWARSN sponged miR-372-3p to promote TXNIP expression. Moreover, nuclear PWARSN interacted and facilitated RNA binding motif protein X-linked (RBMX) degradation through ubiquitination, resulting in the initiation of TXNIP transcription by reducing H3K9me3-enrichment at the TXNIP promoter. Further analysis indicated that PWARSN might be a potential biomarker for DKD.

CONCLUSIONS

These findings illustrate distinct dual molecular mechanisms for PWARSN-modulated TXNIP and PTECs pyroptosis in DKD, presenting PWARSN as a promising therapeutic target for DKD.

Circular RNA circBNC2 inhibits epithelial cell G2-M arrest to prevent fibrotic maladaptive repair

The mechanisms underlying fibrogenic responses after injury are not well understood. Epithelial cell cycle arrest in G2/M after injury is a key checkpoint for determining wound-healing leading to either normal cell proliferation or fibrosis. Here, we identify a kidney- and liver-enriched circular RNA, circBNC2, which is abundantly expressed in normal renal tubular cells and hepatocytes but significantly downregulated after acute ischemic or toxic insult. Loss of circBNC2 is at least partially mediated by upregulation of DHX9. Gain- and loss-of-function studies, both in vitro and in vivo, demonstrate that circBNC2 acts as a negative regulator of cell G2/M arrest by encoding a protein that promotes formation of CDK1/cyclin B1 complexes. Restoring circBNC2 in experimentally-induced male mouse models of fibrotic kidney and liver, decreases G2/M arrested cell numbers with secretion of fibrotic factors, thereby mitigating extracellular matrix deposition and fibrosis. Decreased expression of circBNC2 and increased G2/M arrest of epithelial cells are recapitulated in human ischemic reperfusion injury (IRI)-induced chronic kidney disease and inflammation-induced liver fibrosis, highlighting the clinical relevance. These findings suggest that restoring circBNC2 might represent a potential strategy for therapeutic intervention in epithelial organ fibrosis.

Kidney diseases and long non-coding RNAs in the limelight

The most extensively and well-investigated sequences in the human genome are protein-coding genes, while large numbers of non-coding sequences exist in the human body and are even more diverse with more potential roles than coding sequences. With the unveiling of non-coding RNA research, long-stranded non-coding RNAs (lncRNAs), a class of transcripts &gt;200 nucleotides in length primarily expressed in the nucleus and rarely in the cytoplasm, have drawn our attention. LncRNAs are involved in various levels of gene regulatory processes, including but not limited to promoter activity, epigenetics, translation and transcription efficiency, and intracellular transport. They are also dysregulated in various pathophysiological processes, especially in diseases and cancers involving genomic imprinting. In recent years, numerous studies have linked lncRNAs to the pathophysiology of various kidney diseases. This review summarizes the molecular mechanisms involved in lncRNAs, their impact on kidney diseases, and associated complications, as well as the value of lncRNAs as emerging biomarkers for the prevention and prognosis of kidney diseases, suggesting their potential as new therapeutic tools.

Neat1 promotes acute kidney injury to chronic kidney disease by facilitating tubular epithelial cells apoptosis via sequestering miR-129-5p

Acute kidney injury (AKI) is increasingly identified as a crucial risk factor for progression to CKD. However, the factors governing AKI to CKD progression remain largely unknown. By high-throughput RNA sequencing, we found that Neat1_2, a transcript variant of Neat1, was upregulated in 40-min ischemia/reperfusion injury (IRI), which resulted in the development of renal fibrotic lesions. The upregulation of Neat1_2 in hypoxia-treated TECs was attributed to p53 transcriptional regulation. Gain- and loss-of-function studies, both in vitro and in vivo, demonstrated that Neat1_2 promoted apoptosis of injured TECs induced by IRI and caused tubulointerstitial inflammation and fibrosis. Mechanistically, Neat1_2 shares miRNA response elements with FADD, CASP-8, and CASP-3. Neat1_2 competitively binds to miR-129-5p and prevents miR-129-5p from decreasing the levels of FADD, CASP-8, and CASP-3, and ultimately facilitates TEC apoptosis. Increased expression of Neat1_2 associated with kidney injury and TEC apoptosis was recapitulated in human AKI, highlighting its clinical relevance. These findings suggest that preventing TEC apoptosis by hindering Neat1_2 expression may be a potential therapeutic strategy for AKI to CKD progression.

A protein encoded by circular ZNF609 RNA induces acute kidney injury by activating the AKT/mTORautophagy pathway

Autophagy plays a crucial role in the development and progression of ischemic acute kidney injury (AKI). However, the function and mechanism of circular RNAs (circRNAs) in the regulation of autophagy in ischemic AKI remain unexplored. Herein, we find that circ-ZNF609, originating from the ZNF609 locus, is highly expressed in the kidney after ischemia/reperfusion injury, and urinary circ-ZNF609 is a moderate predictor for AKI in heart disease patients. Overexpression of circ-ZNF609 can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis while inhibiting proliferation in HK-2 cells, which is blocked by silencing circ-ZNF609. Mechanistically, circ-ZNF609 encodes a functional protein consisting of 250 amino acids (aa), termed ZNF609-250aa, the overexpression of which can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis in HK-2 cells in vitro and in AKI kidneys in vivo. The blockade of AKT and mTOR signaling with pharmacological inhibitors is capable of reversing ZNF609-250aa-induced autophagy flux impairment and cell apoptosis in HK-2 cells. The present study demonstrates that highly expressed circ-ZNF609-encoded ZNF609-250aa induces cell apoptosis and AKI by impairing the autophagy flux via an AKT/mTOR-dependent mechanism. These findings imply that targeting circ-ZNF609 may be a novel therapy for ischemic AKI.

Pharmacological Inhibition of S100A4 Attenuates Fibroblast Activation and Renal Fibrosis

The TGF-β/Smad3 signaling pathway is an important process in the pathogenesis of kidney fibrosis. However, the molecular mechanisms are not completely elucidated. The current study examined the functional role of S100A4 in regulating TGF-β/Smad3 signaling in fibroblast activation and kidney fibrosis development. S100A4 was upregulated in the kidney in a murine model of renal fibrosis induced by folic acid nephropathy. Further, S100A4 was predominant in the tubulointerstitial cells of the kidney. Pharmacological inhibition of S100A4 with niclosamide significantly attenuated fibroblast activation, decreased collagen content, and reduced extracellular matrix protein expression in folic acid nephropathy. Overexpression of S100A4 in cultured renal fibroblasts significantly facilitated TGF-β1-induced activation of fibroblasts by increasing the expression of α-SMA, collagen-1 and fibronectin. In contrast, S100A4 knockdown prevented TGF-β1-induced activation of fibroblast and transcriptional activity of Smad3. Mechanistically, S100A4 interacts with Smad3 to stabilize the Smad3/Smad4 complex and promotes their translocation to the nucleus. In conclusion, S100A4 facilitates TGF-β signaling via interaction with Smad3 and promotes kidney fibrosis development. Manipulating S100A4 may provide a beneficial therapeutic strategy for chronic kidney disease.

Sirt7 associates with ELK1 to participate in hyperglycemia memory and diabetic nephropathy via modulation of DAPK3 expression and endothelial inflammation

Diabetic nephropathy (DN) is one of the most serious complications of advanced diabetes, and increases patient mortality. Recently, epigenetics-mediated hyperglycemic memory in pathological process of DN has received attention. The purpose of this study was to determine the underlying mechanism by which sirt7 modulates hyperglycemic memory in DN. In glomerular endothelial cells (GECs) cultured in high glucose and glomeruli of DN patients and rats, an increase in p65 phosphorylation and endothelial adhesion molecule levels persisted after glucose normalization but was reversed by glucose normalization associated with death-associated protein kinase-3 (DAPK3) knockout or DAPK3 inhibitor. High glucose-mediated decrease in sirt7, the deacetylase modulating H3K18-acetylation (H3K18ac), was sustained after normoglycemia. Sirt7 overexpression accompanied by glucose normalization suppressed DAPK3 expression and inflammation in GECs. Moreover, sh-sirt7-induced inflammation was inhibited by si-DAPK3. Furthermore, sirt7 and H3K18ac were located at the DAPK3 promoter region. ELK1 was found to combine with sirt7. si-ELK1 supplemented with normoglycemia inhibited high glucose-induced DAPK3 expression and inflammation in GECs. ELK1 overexpression-mediated inflammation was inhibited by si-DAPK3. In addition, ELK1 and sirt7 were located at the same promoter region of DAPK3. ELK1 overexpression enhanced DAPK3 promoter activity, which disappeared after specific binding site mutation. In vivo, sirt7 overexpression decreased inflammation and improved renal function during insulin treatment of DN rats, whereas insulin alone did not work. Our data demonstrated high glucose-mediated mutual inhibition between sirt7 and ELK1 induced DAPK3 transcription and inflammation despite normoglycemia in GECs, thus forming a vicious cycle and participating in the occurrence of hyperglycemic memory in DN.

Super-enhancer hijacking LINC01977 promotes malignancy of early-stage lung adenocarcinoma addicted to the canonical TGF-β/SMAD3 pathway

BACKGROUND

Lung adenocarcinoma (LUAD) is the leading cause of death worldwide. However, the roles of long noncoding RNAs (lncRNAs) hijacked by super-enhancers (SEs), vital regulatory elements of the epigenome, remain elusive in the progression of LUAD metastasis.

METHODS

SE-associated lncRNA microarrays were used to identify the dysregulated lncRNAs in LUAD. ChIP-seq, Hi-C data analysis, and luciferase reporter assays were utilized to confirm the hijacking of LINC01977 by SE. The functions and mechanisms of LINC01977 in LUAD were explored by a series of in vitro and in vivo assays.

RESULTS

We found that LINC01977, a cancer-testis lncRNA, was hijacked by SE, which promoted proliferation and invasion both in vitro and in vivo. LINC01977 interacted with SMAD3 to induce its nuclear transport, which facilitated the interaction between SMAD3 and CBP/P300, thereby regulating the downstream target gene ZEB1. Additionally, SMAD3 up-regulated LINC09177 transcription by simultaneously binding the promoter and SE, which was induced by the infiltration of M2-like tumor-associated macrophages (TAM2), subsequently activating the TGF-β/SMAD3 pathway. Moreover, LINC01977 expression was positively correlated with TAM2 infiltration and SMAD3 expression, especially in early-stage LUAD. Higher chromatin accessibility in the SE region of LINC01977 was observed with high expression of TGF-β. Early-stage LUAD patients with high LIN01977 expression had a shorter disease-free survival.

CONCLUSIONS

TAM2 infiltration induced a rich TGF-β microenvironment, activating SMAD3 to bind the promoter and the SE of LINC01977, which up-regulated LINC01977 expression. LINC01977 also promoted malignancy via the canonical TGF-β/SMAD3 pathway. LINC01977 hijacked by SE could be a valuable therapeutic target, especially for the treatment of early-stage LUAD.

A novel IFNbeta-induced long non-coding RNA ZAP-IT1 interrupts Zika virus replication in A549 cells

Zika virus (ZIKV) infection can cause severe neurological diseases including neonatal microcephaly and Guillain-Barre syndrome. Long noncoding RNAs (lncRNAs) are the by-products of the transcription process, which are considered to affect viral infection. However, it remains largely unexplored whether host lncRNAs play a role in ZIKV infection. Here, we identified a group of human lncRNAs that were up-regulated upon ZIKV infection and were dependent on the type I interferon (IFN) signaling. Overexpression of lncRNA ZAP-IT1 leads to an impairment of ZIKV infection. Correspondently, deficiency of ZAP-IT1 led to an enhancement of ZIKV infection. We further confirmed that ZAP-IT1, an intronic lncRNA with total 551 ​nt in length, is mainly located in the nuclear upon ZIKV infection. Knockout of ZAP-IT1 also led to the increase of dengue virus (DENV), Japanese encephalitis virus (JEV), or vesicular stomatitis virus (VSV) infection. Mechanically, we found that the antiviral effect of ZAP-IT1 was independent of the type I IFN signaling pathway. Therefore, our data unveiled that host lncRNA ZAP-IT1 induced by the type I IFN signaling, showed robust restriction on ZIKV infection, and even on DENV, JEV, and VSV infection, which may benefit the development of antiviral therapeutics.

Bone marrow mesenchymal stem cells combined with estrogen synergistically promote endometrial regeneration and reverse EMT via Wnt/β-catenin signaling pathway

BACKGROUND

Intrauterine adhesion (IUA) is a clinical disease characterized by the uterine cavity occlusion caused by the damage of the endometrial basal layer. Bone marrow mesenchymal stem cells (BMSCs) transplantation have the potential to promote endometrial regeneration mainly through paracrine ability. Estrogen is an indispensable and important factor in the repair of endometrial damage, which has been reported as a promising and adjunctive therapeutic application for stem cell transplantation therapy. This study aims to investigate the synergistic effect of BMSCs and estrogen on improving the endometrial regeneration and restoring the endometrium morphology in a dual damage model of IUA in rabbits and the underlying molecular mechanisms.

METHODS

BMSCs were isolated and identified by adipogenic and osteogenic differentiation and flow cytometry assays. The rabbit IUA animal model was established by a dual damage method of mechanical curettage and lipopolysaccharide infection. Additionally, we investigated the therapeutic impact of both BMSCs and estrogen either separately or in combination in a rabbit model. The retention of PKH26-labeled BMSCs was observed by vivo fluorescence imaging.The number of endometrial glands and the degree of fibrosis were observed by H&E and Masson staining respectively. Western blotting, Immunohistochemistry and immunofluorescence staining were performed to detect biomarkers related to endometrial epithelium, endometrial fibrosis and EMT. Finally, the protein expression of core molecules of Wnt/β-catenin pathway was detected by Western blotting.

RESULTS

PKH26-labeled fluorescence results revealed that BMSCs appeared and located in the endometrial glands and extracellular matrix area when orthotopic transplanted into the uterine cavity. Histological assays showed that remarkably increasing the number of endometrial glands and decreasing the area of endometrial fibrosis in the BMSCs combined with estrogen treatment group. Moreover, downregulated expression of fibrosis markers (fibronectin, CollagenI, a-SMA) and interstitial markers (ZEB1, Vimentin, N-cadherin), as well as upregulated E-cadherin expression were found in the combined group. Further study of in vivo staining revealed that fluorescence intensity of CK7 was stronger in the combined group than that of direct BMSCs intrauterine transplantation, while vimentin showed the opposite results. Moreover, the protein levels of β-catenin, Axin2, C-myc, CycinE of Wnt/β-catenin signaling pathway increased in the BMSCs combined with estrogen group than in the other treatment groups.

CONCLUSION

BMSCs combined with estrogen can promote the differentiation of stem cells into endometrial epithelial cells to facilitate the regeneration of damaged endometrium. The potential mechanism of the synergistic effect may inhibit the occurrence of EMT by activating the Wnt/β-catenin signaling pathway.

Circ_0114428 promotes proliferation, fibrosis and EMT process of high glucose-induced glomerular mesangial cells through regulating the miR-185-5p/SMAD3 axis

Circular RNA (circRNA) has been confirmed to be the key regulators of diabetic nephropathy (DN) progression. However, the role of circ_0114428 in the DN progression remains unclear. Glomerular mesangial cells (GMCs) were treated with high glucose (HG) to mimic DN cell models in vitro. The expression levels of circ_0114428, microRNA (miR)-185-5p, and SMAD3 mRNA were examined by quantitative real-time PCR. Cell proliferation ability was detected by MTT assay, EdU staining and flow cytometry. The protein levels of proliferation marker, fibrosis markers, epithelial-mesenchymal transition (EMT) markers and SMAD3 were measured by western blot assay. The interaction between miR-185-5p and circ_0114428 or SMAD3 was confirmed via dual-luciferase reporter assay, RIP assay and RNA pull-down assay. Our data showed that circ_0114428 was upregulated in HG-induced GMCs. Circ_0114428 overexpression could aggravate the promotion effect of HG on the proliferation, fibrosis and EMT process of GMCs, while its knockdown had an opposite effect. In the terms of mechanisms, circ_0114428 could sponge miR-185-5p to regulate SMAD3. MiR-185-5p inhibitor could reverse the suppressive effect of circ_0114428 knockdown on the proliferation, fibrosis and EMT process in HG-induced GMCs. Also, SMAD3 overexpression abolished the inhibition of miR-185-5p on the proliferation, fibrosis and EMT process in HG-induced GMCs. Taken together, our data suggested that circ_0114428 might promote DN progression by regulating the miR-185-5p/SMAD3 axis.

Flavin Containing Monooxygenase 2 Prevents Cardiac Fibrosis via CYP2J3-SMURF2 Axis

BACKGROUND

Cardiac fibrosis is a common pathological feature associated with adverse clinical outcome in postinjury remodeling and has no effective therapy. Using an unbiased transcriptome analysis, we identified FMO2 (flavin-containing monooxygenase 2) as a top-ranked gene dynamically expressed following myocardial infarction (MI) in hearts across different species including rodents, nonhuman primates, and human. However, the functional role of FMO2 in cardiac remodeling is largely unknown.

METHODS

Single-nuclei transcriptome analysis was performed to identify FMO2 after MI; FMO2 ablation rats were generated both in genetic level using the CRISPR-cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9) technology and lentivirus-mediated manner. Gain-of-function experiments were conducted using postn-promoter FMO2, miR1a/miR133a-FMO2 lentivirus, and enzymatic activity mutant FMO2 lentivirus after MI.

RESULTS

A significant downregulation of FMO2 was consistently observed in hearts after MI in rodents, nonhuman primates, and patients. Single-nuclei transcriptome analysis showed cardiac expression of FMO2 was enriched in fibroblasts rather than myocytes. Elevated spontaneous tissue fibrosis was observed in the FMO2-null animals without external stress. In contrast, fibroblast-specific expression of FMO2 markedly reduced cardiac fibrosis following MI in rodents and nonhuman primates associated with diminished SMAD2/3 phosphorylation. Unexpectedly, the FMO2-mediated regulation in fibrosis and SMAD2/3 signaling was independent of its enzymatic activity. Rather, FMO2 was detected to interact with CYP2J3 (cytochrome p450 superfamily 2J3). Binding of FMO2 to CYP2J3 disrupted CYP2J3 interaction with SMURF2 (SMAD-specific E3 ubiquitin ligase 2) in cytosol, leading to increased cytoplasm to nuclear translocation of SMURF2 and consequent inhibition of SMAD2/3 signaling.

CONCLUSIONS

Loss of FMO2 is a conserved molecular signature in postinjury hearts. FMO2 possesses a previously uncharacterized enzyme-independent antifibrosis activity via the CYP2J3-SMURF2 axis. Restoring FMO2 expression exerts potent ameliorative effect against fibrotic remodeling in postinjury hearts from rodents to nonhuman primates. Therefore, FMO2 is a potential therapeutic target for treating cardiac fibrosis following injury.

ICAM-1 related long noncoding RNA is associated with progression of IgA nephropathy and fibrotic changes in proximal tubular cells

Intercellular adhesion molecule 1 (ICAM-1) related long noncoding RNA (ICR) is on the antisense strand of ICAM-1 and regulates ICAM-1 expression. ICAM-1 is involved in renal tubulointerstitial injury; however, the expression and clinical implication of ICR are not determined in IgA nephropathy (IgAN). We compared renal ICR levels in 337 IgAN patients with those of 89 biopsy controls, and a markedly increased ICR level was observed in IgAN patients. By Cox proportional hazards models, higher levels of renal ICR were independently associated with disease progression event defined as end-stage renal disease or ≥ 40% decline in estimated glomerular filtration rate. Patients in the highest tertile of renal ICR had a 3.5-fold higher risk for disease progression compared with those in the lowest tertile. The addition of renal ICR to a model with traditional risk factors improved risk prediction of disease progression (net reclassification index: 0.31 [95% CI 0.01–0.50]; integrated discrimination index: 0.10 [95% CI 0.04–0.16]). Inhibition of ICR by transfection with plasmids containing ICR shRNA significantly reduced expression of collagen I and α-SMA, and phosphorylation of Akt and mTOR in TGF-β1- treated HK-2 cells. Our findings suggest that renal ICR might be an independent predictor of IgAN progression and contribute to renal fibrosis.

Signaling pathways of chronic kidney diseases, implications for therapeutics

Chronic kidney disease (CKD) is a chronic renal dysfunction syndrome that is characterized by nephron loss, inflammation, myofibroblasts activation, and extracellular matrix (ECM) deposition. Lipotoxicity and oxidative stress are the driving force for the loss of nephron including tubules, glomerulus, and endothelium. NLRP3 inflammasome signaling, MAPK signaling, PI3K/Akt signaling, and RAAS signaling involves in lipotoxicity. The upregulated Nox expression and the decreased Nrf2 expression result in oxidative stress directly. The injured renal resident cells release proinflammatory cytokines and chemokines to recruit immune cells such as macrophages from bone marrow. NF-κB signaling, NLRP3 inflammasome signaling, JAK-STAT signaling, Toll-like receptor signaling, and cGAS-STING signaling are major signaling pathways that mediate inflammation in inflammatory cells including immune cells and injured renal resident cells. The inflammatory cells produce and secret a great number of profibrotic cytokines such as TGF-β1, Wnt ligands, and angiotensin II. TGF-β signaling, Wnt signaling, RAAS signaling, and Notch signaling evoke the activation of myofibroblasts and promote the generation of ECM. The potential therapies targeted to these signaling pathways are also introduced here. In this review, we update the key signaling pathways of lipotoxicity, oxidative stress, inflammation, and myofibroblasts activation in kidneys with chronic injury, and the targeted drugs based on the latest studies. Unifying these pathways and the targeted therapies will be instrumental to advance further basic and clinical investigation in CKD.

LncRNA-Dependent Mechanisms of Transforming Growth Factor-β: From Tissue Fibrosis to Cancer Progression

Transforming growth factor-β (TGF-β) is a crucial pathogenic mediator of inflammatory diseases. In tissue fibrosis, TGF-β regulates the pathogenic activity of infiltrated immunocytes and promotes extracellular matrix production via de novo myofibroblast generation and kidney cell activation. In cancer, TGF-β promotes cancer invasion and metastasis by enhancing the stemness and epithelial mesenchymal transition of cancer cells. However, TGF-β is highly pleiotropic in both tissue fibrosis and cancers, and thus, direct targeting of TGF-β may also block its protective anti-inflammatory and tumor-suppressive effects, resulting in undesirable outcomes. Increasing evidence suggests the involvement of long non-coding RNAs (lncRNAs) in TGF-β-driven tissue fibrosis and cancer progression with a high cell-type and disease specificity, serving as an ideal target for therapeutic development. In this review, the mechanism and translational potential of TGF-β-associated lncRNAs in tissue fibrosis and cancer will be discussed.

LncRNA136131 suppresses apoptosis of renal tubular epithelial cells in acute kidney injury by targeting the miR-378a-3p/Rab10 axis

The pathogenesis of acute kidney injury (AKI) is not fully understood. To date, the exact role and regulatory mechanism of long non-coding RNA (lncRNA)136131 in AKI remains unclear. Here, we demonstrate that lncRNA136131 in BUMPT cells is induced by antimycin A. Furthermore, after incubating BUMPT cells in antimycin for two hours, lncRNA136131 prevented BUMPT cell apoptosis and cleaved caspase-3 expression. Mechanistically, lncRNA136131 sponged miR-378a-3p and then increased the expression of Rab10 to suppress apoptosis. Finally, I/R-induced decline of renal function, tubular damage, renal tubular cells apoptosis, and the upregulation of cleaved caspase-3 were aggravated by lncRNA136131 siRNA. In contrast, this effect was attenuated by the overexpression of lncRNA136131. In conclusion, lncRNA136131 protected against I/R-induced AKI progression by targeting miR-378a-3p/Rab10 and may be utilized as a novel target for AKI therapeutics.

The SETD8/ELK1/bach1 complex regulates hyperglycaemia-mediated EndMT in diabetic nephropathy

Background

Diabetic nephropathy (DN), the most common microvascular complication in patients with diabetes, induces kidney failure. Previous research showed that endothelial-to-mesenchymal transition (EndMT) of human glomerular endothelial cells (HGECs) is involved in the progression of DN. Moreover, SET domain-containing protein 8 (SETD8), ETS-domain containing protein (ELK1) and BTB and CNC homology 1 (bach1) all participate in endothelial injury. In this study, we hypothesize that the SETD8/ELK1/bach1 functional axis is involved in mediating EndMT in diabetic nephropathy.

Methods

Immunohistochemistry, Western blotting and qPCR were performed to determine the protein and mRNA levels of genes in HGECs and the kidney tissues of participants and rats. Immunofluorescence, Co-IP and GST pulldown assays were performed to verify the direct interaction between SETD8 and ELK1. ChIP and dual-luciferase assays were performed to determine the transcriptional regulation of bach1 and Snail. AVV-SETD8 injection in rat kidney was used to verify the potential protective effect of SETD8 on DN.

Results

Our current study showed that hyperglycaemia triggered EndMT by increasing Snail expression both in vitro and in vivo. Moreover, high glucose increased bach1 expression in HGECs, positively regulating Snail and EndMT. As a transcription factor, ELK1 was augmented and participated in hyperglycaemia-induced EndMT via modulation of bach1 expression. Moreover, ELK1 was found to associate with SETD8. Furthermore, SETD8 negatively regulated EndMT by cooperating with bach1 to regulate Snail transcription. Furthermore, histone H4-Lys-20 monomethylation (H4K20me1), which is downstream of SETD8, was accompanied by ELK1 localization at the same promoter region of bach1. ELK1 overexpression enhanced bach1 promoter activity, which disappeared after specific binding site deletion. Mutual inhibition between ELK1 and SETD8 was found in HGECs. In vivo, SETD8 overexpression decreased ELK1 and bach1 expression, as well as EndMT. Moreover, SETD8 overexpression improved the renal function of rats with DN.

Conclusions

SETD8 cooperates with ELK1 to regulate bach1 transcription, thus participating in the progression of DN. In addition, SETD8 interacts with bach1 to modulate Snail transcription, thus inducing EndMT in DN. SETD8 plays a core role in the SETD8/ELK1/bach1 functional axis, which participates in hyperglycaemia-mediated EndMT in DN, and SETD8 may be a potential therapeutic target for DN.

Trial registration ChiCTR, ChiCTR2000029425. 2020/1/31, http://www.chictr.org.cn/showproj.aspx?proj=48548

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03352-4.

Gut microbiota-derived metabolite trimethylamine-N-oxide and multiple health outcomes: an umbrella review and updated meta-analysis

BACKGROUND

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite produced from dietary nutrients. Many studies have discovered that circulating TMAO concentrations are linked to a wide range of health outcomes.

OBJECTIVES

This study aimed to summarize health outcomes related to circulating TMAO concentrations.

METHODS

We searched the Embase, Medline, Web of Science, and Scopus databases from inception to 15 February, 2022 to identify and update meta-analyses examining the associations between TMAO and multiple health outcomes. For each health outcome, we estimated the summary effect size, 95% prediction CI, between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. These metrics were used to evaluate the evidence credibility of the identified associations.

RESULTS

This umbrella review identified 24 meta-analyses that investigated the association between circulating TMAO concentrations and health outcomes including all-cause mortality, cardiovascular diseases (CVDs), diabetes mellitus (DM), cancer, and renal function. We updated these meta-analyses by including a total of 82 individual studies on 18 unique health outcomes. Among them, 14 associations were nominally significant. After evidence credibility assessment, we found 6 (33%) associations (i.e., all-cause mortality, CVD mortality, major adverse cardiovascular events, hypertension, DM, and glomerular filtration rate) to present highly suggestive evidence.

CONCLUSIONS

TMAO might be a novel biomarker related to human health conditions including all-cause mortality, hypertension, CVD, DM, cancer, and kidney function. Further studies are needed to investigate whether circulating TMAO concentrations could be an intervention target for chronic disease.This review was registered at www.crd.york.ac.uk/prospero/ as CRD42021284730.

TGF-β/Smad Signaling Pathway in Tubulointerstitial Fibrosis

Chronic kidney disease (CKD) was a major public health problem worldwide. Renal fibrosis, especially tubulointerstitial fibrosis, is final manifestation of CKD. Many studies have demonstrated that TGF-β/Smad signaling pathway plays a crucial role in renal fibrosis. Therefore, targeted inhibition of TGF-β/Smad signaling pathway can be used as a potential therapeutic measure for tubulointerstitial fibrosis. At present, a variety of targeting TGF-β1 and its downstream Smad proteins have attracted attention. Natural products used as potential therapeutic strategies for tubulointerstitial fibrosis have the characteristics of acting on multiple targets by multiple components and few side effects. With the continuous research and technique development, more and more molecular mechanisms of natural products have been revealed, and there are many natural products that inhibited tubulointerstitial fibrosis via TGF-β/Smad signaling pathway. This review summarized the role of TGF-β/Smad signaling pathway in tubulointerstitial fibrosis and natural products against tubulointerstitial fibrosis by targeting TGF-β/Smad signaling pathway. Additionally, many challenges and opportunities are presented for inhibiting renal fibrosis in the future.

LINC01605 knockdown induces apoptosis in human Tenon's capsule fibroblasts by inhibiting autophagy

Glaucoma is an irreversible disease that causes blindness. Formation of a hypertrophic scar (HS) is the main cause of failure of glaucoma surgery. The long non-coding RNA LINC01605 is closely associated with the formation of HS; however, the function of LINC01605 in the formation and development of HS remains unclear. For this study, firstly, human Tenon's capsule fibroblasts (HTFs) and corneal epithelial cells (control cells) were collected from patients (n=5) with POAG who underwent glaucoma filtration surgery at Fuyang People's Hospital. Immunofluorescence analysis was performed to detect the expression levels of vimentin (one of the main components of medium fiber and plays an important role in the cytoskeleton and motility), keratin (the main component of cytoskeletal proteins) and LC3 (an autophagy marker). In addition, reverse transcription-quantitative PCR analysis was performed to detect LINC01605 expression. Besides, the Cell Counting Kit-8 assay was performed to assess the viability of human Tenon's capsule fibroblasts (HTFs). Next, flow cytometry was performed to detect HTF apoptosis. Furthermore, western blot analysis was performed for Bax, Bcl-2, Pro-caspase-3, cleaved caspase-3, phosphorylated (p-)Smad2, Smad2, α-SMA, MMP9, ATG7, p62, beclin 1, p-AMPK and AMPK in HTFs to determine the mechanism by which LINC01605 regulates the formation and development of HS. Moreover, a Transwell assay was performed to detect the migratory ability of HTFs. The results demonstrated that LINC01605 was significantly upregulated in HS tissues compared with that in normal (control/healthy) tissues. In addition, vimentin was highly expressed in HTFs, whereas keratin was expressed at a low level. Also, in HTFs, LINC01605 knockdown inhibited cell viability by inducing apoptosis, decreasing Smad2 activation and inhibiting autophagy. Furthermore, LINC01605 knockdown significantly inhibited the migratory ability of HTFs. Transfection with LINC01605 small interference RNAs significantly downregulated the expression levels of p-Smad2, α-SMA and MMP9 in HTFs. Furthermore, LINC01605 knockdown notably inhibited the viability and migration, and induced the apoptosis of HTFs, the effects of which were reversed following treatment with TGF-β. Taken together, the results of the present study suggested that LINC01605 knockdown may inhibit the viability of HTFs by inducing the apoptotic pathway. These findings may provide novel directions for the treatment of HS.

Green tea peptides ameliorate diabetic nephropathy by inhibiting the TGF-β/Smad signaling pathway in mice

Diabetic nephropathy (DN) is the most important cause of middle and late-stage chronic kidney disease. Green tea polypeptides are extracted from tea pomace, and exhibit various pharmacological effects. In this study, we analyzed the reno-protective effects of green tea peptides in diabetic db/db mice, and explored the underlying mechanisms. Peptide treatment for 5 weeks significantly reduced the blood glucose levels and other indices of diabetes, and alleviated renal injury measured in terms of blood creatinine, urea nitrogen and urinary albumin/urinary creatinine levels. Mechanistically, the green tea peptides downregulated p-Smad2/3, α-SMA, ZO-1 and vimentin proteins in the kidney tissues, and elevated Smad7. Thus, green tea peptides inhibited the deposition of ECM proteins by suppressing excessive activation of the TGF-β/Smad signaling pathway and reducing fibronectin levels. On the other hand, tea peptides ameliorated renal injury by inhibiting the production of inflammatory factors (iNOS and TNF-α) by suppressing the NF-κB signaling pathway. In addition, we confirmed the inhibitory effect of green tea peptides on the TGF-β/Smad signaling pathway in TGF-β1-stimulated HK-2 cells. Therefore, tea peptides can be considered as an effective candidate for alleviating DN.

Signaling pathways and targeted therapy for myocardial infarction

Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.

Druggability of lipid metabolism modulation against renal fibrosis

Renal fibrosis contributes to progressive damage to renal structure and function. It is a common pathological process as chronic kidney disease develops into kidney failure, irrespective of diverse etiologies, and eventually leads to death. However, there are no effective drugs for renal fibrosis treatment at present. Lipid aggregation in the kidney and consequent lipotoxicity always accompany chronic kidney disease and fibrosis. Numerous studies have revealed that restoring the defective fatty acid oxidation in the kidney cells can mitigate renal fibrosis. Thus, it is an important strategy to reverse the dysfunctional lipid metabolism in the kidney, by targeting critical regulators of lipid metabolism. In this review, we highlight the potential "druggability" of lipid metabolism to ameliorate renal fibrosis and provide current pre-clinical evidence, exemplified by some representative druggable targets and several other metabolic regulators with anti-renal fibrosis roles. Then, we introduce the preliminary progress of noncoding RNAs as promising anti-renal fibrosis drug targets from the perspective of lipid metabolism. Finally, we discuss the prospects and deficiencies of drug targeting lipid reprogramming in the kidney.

Small nucleolar RNA SNORA71A promotes epithelial-mesenchymal transition by maintaining ROCK2 mRNA stability in breast cancer

Metastasis is the primary reason of death in patients with cancer. Small nucleolar noncoding RNAs (snoRNAs) are conserved 60–300 nucleotide noncoding RNAs, involved in post‐transcriptional regulation of mRNAs and noncoding RNAs. Despite their essential roles in cancer, the roles of snoRNAs in epithelial‐mesenchymal transition (EMT)‐induced metastasis have not been studied extensively. Here, we used small RNA sequencing to screen for snoRNAs related to EMT and breast cancer metastasis. We found a higher expression of SNORA71A in metastatic breast cancer tissues compared to nonmetastatic samples. Additionally, SNORA71A promoted the proliferation, migration, invasion and EMT of MCF‐7 and MDA‐MB‐231 cells. Mechanistically, SNORA71A elevated mRNA and protein levels of ROCK2, a negative regulator of TGF‐β signaling. Rescue assays showed ROCK2 abrogated the SNORA71A‐mediated increase in proliferation, migration, invasion and EMT. Binding of SNORA71A to mRNA stability regulatory protein G3BP1, increased ROCK2 mRNA half‐life. Furthermore, G3BP1 depletion abolished the SNORA71A‐mediated upregulation of ROCK2. In vivo, SNORA71A overexpression promoted breast tumor growth, and SNORA71A knockdown inhibited breast cancer growth and metastasis. We suggest SNORA71A enhances metastasis of breast cancer by binding to G3BP1 and stabilizing ROCK2.

The methyl-CpG-binding domain 2 facilitates pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation

Although DNA methylation has been recognized in the pathogenesis of idiopathic pulmonary fibrosis (IPF), the exact mechanisms, however, are yet to be fully addressed. Herein, we demonstrated that lungs originated from IPF patients and mice after bleomycin (BLM)-induced pulmonary fibrosis are characterized by the altered DNA methylation along with overexpression of methyl-CpG-binding domain 2 (MBD2) in myofibroblasts, a reader responsible for interpreting DNA methylome-encoded information. Specifically, depletion of Mbd2 in fibroblasts or myofibroblasts protected mice from BLM-induced pulmonary fibrosis coupled with a significant reduction of fibroblast differentiation. Mechanistically, TGF-β1 induced a positive feedback regulatory loop between transforming growth factor-β receptor I (TβRI), Smad3 and Mbd2, and erythroid differentiation regulator 1 (Erdr1). TGF-β1 induced fibroblasts to undergo a global DNA hypermethylation along with Mbd2 overexpression in a TβRI/Smad3 dependent manner, and Mbd2 selectively bound to the methylated CpG DNA within the Erdr1 promoter to repress its expression, through which it enhances TGF-β/Smads signaling to promote fibroblast differentiating into myofibroblast and exacerbate pulmonary fibrosis. Therefore, enhancing Erdr1 expression strikingly reversed established pulmonary fibrosis. Collectively, our data support that strategies aimed at silencing Mbd2 or increasing Erdr1 could be viable therapeutic approaches for prevention and treatment of pulmonary fibrosis in clinical settings.

Long noncoding RNA NEAT1 promotes cardiac fibrosis in heart failure through increased recruitment of EZH2 to the Smad7 promoter region

Cardiac fibrosis, a well-known major pathological process that ultimately leads to heart failure, has attracted increasing attention and focus in recent years. A large amount of research indicates that long noncoding RNAs (lncRNAs) play an important role in cardiac fibrosis, but little is known about the specific function and mechanism of the lncRNA NEAT1 in the progression of cardiac fibrosis to heart failure. In the present study, we have demonstrated that the lncRNA NEAT1 is upregulated in patients with heart failure. Similarly, the expression of Neat1 was also increased in the left ventricular tissue of transverse aortic constriction (TAC) surgery mice and cardiac fibroblasts treated with TGF-β1. Further, gain-of-function and loss-of-function experiments showed that silencing of Neat1 attenuated cardiac fibrosis, while overexpression of Neat1 with adenovirus significantly aggravated the in vitro progression of fibrosis. With regard to the underlying mechanism, our experiments showed that Neat1 recruited EZH2 to the promoter region of Smad7 through physical binding of EZH2 to the promoter region, as a result of which Smad7 expression was inhibited and the progression of cardiac fibrosis was ultimately exacerbated. We found that the introduction of shNeat1 carried by adeno-associated virus-9 significantly ameliorated cardiac fibrosis and dysfunction caused by TAC surgery in mice. Overall, our study findings demonstrate that the lncRNA Neat1 accelerates the progression of cardiac fibrosis and dysfunction by recruiting EZH2 to suppress Smad7 expression. Thus, NEAT1 may serve as a target for the treatment of cardiac fibrosis.

A hierarchical bilayer architecture for complex tissue regeneration

Engineering a complete, physiologically functional, periodontal complex structure remains a great clinical challenge due to the highly hierarchical architecture of the periodontium and coordinated regulation of multiple growth factors required to induce stem cell multilineage differentiation. Using biomimetic self-assembly and microstamping techniques, we construct a hierarchical bilayer architecture consisting of intrafibrillarly mineralized collagen resembling bone and cementum, and unmineralized parallel-aligned fibrils mimicking periodontal ligament. The prepared biphasic scaffold possesses unique micro/nano structure, differential mechanical properties, and growth factor-rich microenvironment between the two phases, realizing a perfect simulation of natural periodontal hard/soft tissue interface. The interconnected porous hard compartment with a Young's modulus of 1409.00 ± 160.83 MPa could induce cross-arrangement and osteogenic differentiation of stem cells in vitro, whereas the micropatterned soft compartment with a Young's modulus of 42.62 ± 4.58 MPa containing abundant endogenous growth factors, could guide parallel arrangement and fibrogenic differentiation of stem cells in vitro. After implantation in critical-sized complete periodontal tissue defect, the biomimetic bilayer architecture potently reconstructs native periodontium with the insertion of periodontal ligament fibers into newly formed cementum and alveolar bone by recruiting host mesenchymal stem cells and activating the transforming growth factor beta 1/Smad3 signaling pathway. Taken together, integration of self-assembly and microstamping strategies could successfully fabricate a hierarchical bilayer architecture, which exhibits great potential for recruiting and regulating host stem cells to promote synergistic regeneration of hard/soft tissues.

Advances in the identification of long non-coding RNA binding proteins

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nt without evident protein coding function. They play important regulatory roles in many biological processes, e.g., gene regulation, chromatin remodeling, and cell fate determination during development. Dysregulation of lncRNAs has been observed in various diseases including cancer. Interacting with proteins is a crucial way for lncRNAs to play their biological roles. Therefore, the characterization of lncRNA binding proteins is important to understand their functions and to delineate the underlying molecular mechanism. Large-scale studies based on mass spectrometry have characterized over a thousand new RNA binding proteins without known RNA-binding domains, thus revealing the complexity and diversity of RNA-protein interactions. In addition, several methods have been developed to identify the binding proteins for particular RNAs of interest. Here we review the progress of the RNA-centric methods for the identification of RNA-protein interactions, focusing on the studies involving lncRNAs, and discuss their strengths and limitations.

Metabolic Reprogramming and Renal Fibrosis

There are several causes of chronic kidney disease, but all of these patients have renal fibrosis. Although many studies have examined the pathogenesis of renal fibrosis, there are still no effective treatments. A healthy and balanced metabolism is necessary for normal cell growth, proliferation, and function, but metabolic abnormalities can lead to pathological changes. Normal energy metabolism is particularly important for maintaining the structure and function of the kidneys because they consume large amounts of energy. We describe the metabolic reprogramming that occurs during renal fibrosis, which includes changes in fatty acid metabolism and glucose metabolism, and the relationship of these changes with renal fibrosis. We also describe the potential role of novel drugs that disrupt this metabolic reprogramming and the development of fibrosis, and current and future challenges in the treatment of fibrosis.