Ischemia-reperfusion (I/R) injury represents a prevalent etiology of permanent vision loss across multiple ocular pathologies. Apoptotic death and inflammation of retinal ganglion cells (RGCs) induced by I/R injury constitutes a major contributor to visual dysfunction. Nevertheless, the molecular mechanisms that initiate the apoptotic and inflammation cascade in RGCs remain largely uncharacterized. Recent investigations have demonstrated that PRD1-BF1-RIZ1 homeodomain protein 16 (PRDM16) attenuates renal cell death in acute kidney injury. However, its specific function and regulatory mechanisms in I/R-induced RGCs apoptosis and inflammation remain poorly understood. Here, we demonstrate that PRDM16 expression is markedly upregulated in RGCs and mouse retinas following I/R injury. Functionally, PRDM16 overexpression markedly attenuates I/R-induced RGCs apoptosis and inflammation, while its RGC-specific deletion exacerbates retinal structural damage and functional deficits. Mechanistically, PRDM16 binds to the Ribosomal Protein L5 (RPL5) promoter and enhances its transcription. Additionally, co-immunoprecipitation assays revealed a physical association between PRDM16 and RPL5. This PRDM16-mediated enrichment of RPL5 subsequently suppresses p53 signaling, leading to the upregulation of FCGR2B. Increased FCGR2B, in turn, inhibits the overactivation of MAPK (p38 and JNK) signaling and the assembly of the NLRP3/IL-1β inflammasome axis. In conclusion, these findings identify PRDM16 as a critical endogenous protective regulator that alleviates retinal I/R-induced damage through modulation of the RPL5/p53/FCGR2B/MAPK axis. Targeting PRDM16 regulatory networks may therefore represent a promising therapeutic strategy for retinal ischemic diseases. Ischemia–reperfusion injury induces apoptosis and inflammation in RGCs. PRDM16 is upregulated in response to ischemic stress and exerts a protective effect by transcriptionally activating RPL5. Increased RPL5 suppresses p53 expression, leading to upregulation of FCGR2B and subsequent inhibition of p38 MAPK and JNK signaling. Additionally, co-immunoprecipitation assays reveal a physical association between PRDM16 and RPL5. This regulatory cascade attenuates caspase-3 activation and inflammatory mediator (NLRP3 and IL-1β) expression, ultimately protecting RGCs from ischemia-induced injury.

Multiple organ dysfunction syndrome presents a significant challenge in clinical critical care, characterized by the progressive or simultaneous failure of two or more organ systems following severe insults such as infection, trauma, acute pancreatitis, shock, burns, or other major events. Recent advancements in research have deepened the understanding of organ dysfunction, with a shift toward investigating organ injury and organ-specific diseases. The pathogenesis of MODS is intricate and driven by dynamic interactions across multiple levels, including inflammatory responses, microcirculatory disruptions, coagulation abnormalities, cell death, DNA damage and the production of reactive oxygen species. Recent innovations in single-cell technologies, spatial omics and organoid models have opened new avenues for exploring intercellular signaling, targeting damaged tissues and advancing drug development. Current therapeutic approaches for MODS involve comprehensive strategies, such as aggressive management of underlying causes, organ support, modulation of immune and inflammatory responses, nutritional intervention and stabilization of the internal environment. Despite these efforts, mortality rates remain high, and therapeutic advancements have yet to yield optimal results. This highlights the urgent need for continued research to translate scientific discoveries into clinical breakthroughs. Further exploration of the disease’s pathogenesis, identification of early diagnostic biomarkers and development of novel, effective treatments are crucial to improving treatment outcomes and reducing mortality in critically ill patients.

Progressing from acute kidney injury (AKI) to chronic kidney disease (CKD) is acknowledged as a significant clinical challenge. Our recent works indicated that PR domain-containing 16 (PRDM16) impedes the progression of AKI and DKD. Nonetheless, the specific function and regulatory mechanism of PRDM16 during the AKI to CKD transition remain incompletely understood. In this investigation, it was identified that PRDM16 mitigates TGF-β1-induced renal tubulointerstitial fibrosis in BUMPT cells. From a mechanistic perspective, PRDM16 was found to enhance the expression of eif6, which subsequently suppressed TGF-β, CTGF, and NLRP3 levels via the suppression of the Wnt/β-catenin/SP1 signaling cascade. Additionally, knock-in of PRDM16 in kidney proximal tubules resulted in increased expression of eIF6, thereby restraining the stimulation of the Wnt/β-catenin/SP1 pathway, reducing the production of TGF-β, CTGF, and NLRP3, and consequently limiting renal tubulointerstitial fibrosis progression in both unilateral ureteral obstruction and ischemia-reperfusion-injury mouse models.Moreover, overexpression of PRDM16 following ischemia-induced AKI was shown to attenuate renal tubulointerstitial fibrosis and the eIF6/Wnt/β-catenin/SP1/TGF-β, CTGF, and NLRP3 axis. Finally, the PRDM16/eIF6/Wnt/β-catenin/SP1/TGF-β, CTGF, and NLRP3 axis were analyzed in renal biopsies from individuals with minimal change disease and severe obstructive nephropathy. Collectively, these findings indicate that PRDM16-mediated eIF6 induction serves to impede the transition from AKI to CKD by suppressing the Wnt/β-catenin/SP1/TGF-β, CTGF, and NLRP3 axis.

Cisplatin (CDDP), a commonly utilized anti-tumor drug, leads to acute kidney injury (AKI) and chronic kidney disease (CKD). The mechanisms and therapeutic approaches for injury in AKI have been extensively studied, but the mechanisms resulting in CKD are poorly comprehended and intervention methods are scarce. In the current study, we found that under different phases of the repeated low-dose CDDP treatment, Mettl3 expression was induced by two different mechanisms. In the presence of CDDP, the transcription factor Hif1-α was induced, resulting in an increase in Mettl3. When CDDP was removed, the previously increased Mettl3 caused an elevated lactate level, which formed a positive feedback loop by mutually reinforcing each other's expression via H3K18 lactylation. Functionally, we disclose that the knockout of Mettl3 in proximal tubules mitigates repeated low-dose CDDP-induced renal fibrosis both in vitro and in vivo. Mechanistically, Mettl3 stabilizes Pfkfb3 mRNA through N6-methyladenosine (m6A) modification and subsequently induces lactate production to upregulate the PD-L1 expression via H3K18 lactylation, thereby promoting both tumor growth and CDDP-induced renal damage. Intriguingly, we discovered that Levosimendan suppresses the methyltransferase activity of Mettl3 to lower the m6A level but has no impact on the abundance of the Mettl3-Mettl14 complex. PLGA-encapsulated Levosimendan not only alleviates repeated low-dose CDDP-induced renal fibrosis, but also significantly enhances the chemotherapeutic effects of cisplatin in several xenograft and syngeneic mouse tumor models by suppressing the Mettl3/Pfkfb3/lactate/ H3K18la/PD-L1 axis. Collectively, targeting Mettl3 might offer an effective therapeutic strategy during cisplatin-based chemotherapy-induced renal fibrosis, and PLGA-encapsulated Levosimendan is a potential intervention approach.

Purpose:Retinal fibrosis, a hallmark of proliferative diabetic retinopathy (PDR), contributes to retinal detachment and irreversible vision loss. This research aimed to explore the roles and regulatory mechanisms of long noncoding RNA (lncRNA) LINC02099 in extracellular matrix (ECM) deposition in the retina, an essential process in retinal fibrosis associated with PDR. Methods:A lncRNA microarray analysis was conducted to identify differentially expressed lncRNAs in vitreous specimens from patients with PDR. An in vitro high-glucose (HG) (25 mM) model was established in Müller cells, while an in vivo diabetic mouse model was generated via intraperitoneal streptozotocin injection. Real-time quantitative PCR was utilized to detect the expression of lncRNAs, microRNAs, and target gene mRNAs. Western blotting and immunofluorescence staining were utilized to evaluate ECM deposition. The competitive endogenous RNA network involving LINC02099, miRNA-214-3p, and its target gene was analyzed using fluorescence in situ hybridization and dual-luciferase reporter assays. Additionally, scotopic electroretinography was performed to assess visual function in the treated mice. Results:LINC02099 was the most highly expressed lncRNA in vitreous samples from patients with PDR. Overexpression of LINC02099 exacerbated HG-induced upregulation of fibronectin, collagen I, and collagen IV in Müller cells, while LINC02099 knockdown produced the opposite effect. Mechanistically, LINC02099 was found to directly interact with miR-214-3p. Introduction of a miR-214-3p mimic significantly suppressed HG-induced expression of fibronectin, collagen I, and collagen IV. Cathepsin S (CTSS) was identified as a direct target of miR-214-3p, and its knockdown attenuated HG-induced expression of these ECM components. Furthermore, LINC02099 knockdown reduced the expression levels of fibronectin, collagen I, and collagen IV by downregulating CTSS expression under HG conditions, a process that was significantly reversed by inhibition of miR-214-3p. Finally, in vivo experiments confirmed that LINC02099 overexpression aggravated ECM deposition in the retinas of diabetic mice via the miR-214-3p/CTSS axis. Conclusions:This study establishes the LINC02099/miRNA-214-3p/CTSS axis as a novel regulatory mechanism in PDR-associated retinal ECM expression. Targeting this pathway may provide new therapeutic strategies for managing PDR and enhancing outcomes for patients with advanced diabetic retinopathy.

PURPOSE. Proliferative diabetic retinopathy (PDR) is a severe microvascular complication of diabetes mellitus. Although exosomes participate in various pathologic processes, their role in ocular pathologies is unclear. This study profiled exosomal microRNAs (exomiRNAs) in the vitreous humor (VH) of patients with PDR to elucidate their regulatory roles in PDR pathogenesis. METHODS. VH samples were obtained from 23 patients with PDR and 17 non-diabetic controls. Exosomes were isolated using ultracentrifugation and characterized via transmission electron microscopy, nanoparticle tracking analysis and Western blot. Highthroughput sequencing identified differentially expressed miRNAs (DEMs), followed by target gene prediction and bioinformatic analyses. The top DEMs were validated using quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS. Exosomes were isolated and characterized from VH samples. Sequencing analysis identified 843 unique miRNAs, with 60 showing significant differential expression between PDR and control groups (28 upregulated and 32 downregulated). The miR-451a and miR-486-5p were most upregulated; miR-204-5p and miR-211-5p were most downregulated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed DEM target genes enriched in endocrine, metabolic, signaling transduction, and intercellular adhesion pathways, notably cGMP-PKG, mTOR, and cAMP pathways. Network analysis identified miR-486-5p and miR-451a as key hubs. Validation by qRT-PCR confirmed the differential expression in the sequencing analysis. CONCLUSIONS. This study provides the comprehensive profile of vitreous exo-miRNAs in patients with PDR, identifying key DEMs and their potential regulatory networks. These findings indicate that vitreous exo-miRNAs, specifically miR-204-5p and miR486-5p, represent promising diagnostic biomarkers and potential therapeutic targets for PDR.

Previous studies have indicated that PRDM16 suppresses apoptosis and ferroptosis, thereby mitigating the development of AKI triggered by ischemia, cisplatin, and sepsis. Nevertheless, the exact function and control mechanisms of PRDM16 in rhabdomyolysis-induced AKI are not fully understood. In this investigation, PRDM16 was found to inhibit ferrous myoglobin-induced pyroptosis in Boston University mouse proximal tubule (BUMPT) cells. At the molecular level, PRDM16 binds to the USP10 promoter, enhancing its expression and subsequently inhibiting the NLRP3-Caspase1-GSDMD and Caspase3-GSDME pathways. Rhabdomyolysis-induced AKI was alleviated in PRDM16 KI mice, whereas PRDM16 KO exacerbated the condition. Furthermore, PNPs-encapsulated formononetin significantly attenuated the progression of rhabdomyolysis-induced AKI. In conclusion, PRDM16 suppresses pyroptosis and ameliorates rhabdomyolysis-induced AKI by regulating the USP10/NLRP3-Caspase1-GSDMD and Caspase3-GSDME pathways. PNPs-encapsulated formononetin emerges as a promising therapeutic strategy.

Myofibroblasts combine features of fibroblasts and smooth muscle cells, and they are reactive cells present under injury conditions. This study was performed to explore the mechanism that methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2 (MTHFD2) mediated m6A modification in sepsis-induced AKI (SAKI) through regulating the collagen accumulation in myofibroblasts. Gene expression microarrays related to SAKI were obtained from the GEO database, and the hub protein involved was screened using PPI. The SAKI mice were induced by cecal ligation and puncture (CLP). MTHFD2 expression was significantly elevated in the kidneys of CLP-induced mice, and SAKI was ameliorated by knocking down MTHFD2 in kidney tissues. MTHFD2 promoted N6-methyladenosine (m6A) modification in kidney tissues of CLP-induced mice by increasing the content of methylated donor s-adenosylmethionine (SAM). MTHFD2 enhanced LOX mRNA stability in an m6A modification-dependent manner, thereby promoting its expression. Knockdown of MTHFD2 inhibited collagen accumulation in myofibroblasts, whereas overexpression of LOX accelerated fibrosis and SAKI in mice in the presence of sh-MTHFD2. In conclusion, our results show that MTHFD2 promotes LOX expression in an m6A-dependent manner, thereby mediating SAKI progression.

Sepsis -associated acute kidney injury (SA-AKI) contributes substantially to mortality and morbidity in critically ill individuals. Although considerable investigation has been conducted, effective therapeutic strategies preventing its advancement remain unavailable, highlighting the importance of understanding its fundamental mechanisms. Previous research identified mmu_circ_26986/hsa_circ_0072463 as a prospective biomarker and treatment target for SA-AKI. The current investigation reveals that mmu_circ_0001022 displays increased expression in BUMPT cells(Boston University Mouse Proximal Tubular Epithelial cell line)and C57BL/6 mouse kidneys following lipopolysaccharide (LPS) exposure and cecal ligation and puncture (CLP). Experimental analyses indicate that mmu_circ_0001022 diminishes LPS-triggered apoptosis in BUMPT cells. The molecular mechanism involves sequestering miRNA-92a-2-5p, subsequently enhancing SKI expression. Enhanced mmu_circ_0001022 expression reduces CLP-initiated acute kidney injury (AKI) progression through the miRNA-92a-2-5p/SKI pathway. Research demonstrates that hsa_ circ_0056869, the mmu_circ_0001022 homologous form, reduces LPS-initiated apoptosis in HK-2 cells (Human Kidney 2 cell line) via the miRNA-92a-2-5p/SKI pathway. Notably, septic patients experiencing AKI demonstrated elevated hsa_circ_0056869 plasma concentrations versus non-AKI cases. Analysis revealed hsa_circ_0056869 exhibited 79.41 % sensitivity, 82.35 % specificity, and 0.8175 area under the curve. A marked positive association emerged between hsa_circ_0056869 plasma levels and serum creatinine in septic individuals (r = 0.786). These findings establish the mmu_circ_0001022/hsa_circ_0056869-miRNA-92a-2-5p/SKI pathway as significant in SA-AKI pathogenesis. In addition, our data indicate that hsa_circ_0056869 may serve as an early diagnosis marker for the septic AKI.

AbstractAcute kidney injury (AKI) presents as a condition marked by a sudden and rapid decrease in kidney function over a short timeframe, resulting from diverse causes. As a transcription factor, PR domain‐containing 16 (PRDM16), has recently been implicated in brown fat biogenesis and heart diseases. Our recent works indicated that PRDM16 could suppress the occurrence of renal interstitial fibrosis in diabetic kidney disorder. Nonetheless, the effect and regulatory mechanism of PRDM16 in AKI remain elusive. Our study demonstrated that PRDM16 inhibited apoptosis induced by ischemic/reperfusion (I/R) in BUMPT (Boston University mouse kidney proximal tubular) cells and HK‐2(Human Kidney‐2) cells. Mechanistically, PRDM16 not only bound to the promoter region of S100 Calcium Binding Protein A6 (S100A6)and upregulated its expression but also interacted with its amino acids 945–949, 957–960, and 981–984 to suppress the p38MAPK and JNK axes via inhibition of PKC‐η activity and mitochondrial reactive oxygen species (ROS) production. Furthermore, cisplatin‐ and I/R‐stimulated AKI progression were ameliorated in PRDM16 proximal‐tubule‐specific knockin mice, whereas exacerbated in PRDM16 knockout proximal‐tubule‐specific mice). Moreover, we observed that formononetin ameliorated I/R‐ and cisplatin‐triggered AKI progression in mice. Taken together, these findings reveal a novel self‐protective mechanism in AKI, whereby PRDM16 regulates the S100A6/PKC‐η/ROS/p38MAPK and JNK pathways to inhibit AKI progression.

Approximately 60% of septic patients developed acute kidney injury (AKI). The mortality rate of septic AKI (SA-AKI) is two to three times higher than that of septic without AKI (SA-non-AKI). The actual functions and mechanisms of CircRNAs in the pathophysiology of SA-AKI remain incompletely understood. Herein, we observed that the mmu_Circ_26986 could be induced by lipopolysaccharide (LPS) and cecum ligation and puncture (CLP) in BUMPT cell line and C57BL/6 mouse kidney, respectively. Functionally, mmu_Circ_26986 suppressed BUMPT cell apoptosis induced by LPS. Mechanistically, mmu_Circ_26986 sponged miRNA-29b-1-5p to upregulate the expression of PAK7. Overexpression of mmu_Circ_26986 ameliorated the progression of CLP-stimulated AKI through miRNA-29b-1-5p/PAK7 axis. In addition, we found that hsa_Circ_0072463, homologous to mmu_Circ_26986, suppressed LPS-induced HK-2 cells apoptosis via regulation of miRNA-29b-1-5p/PAK7 axis. Furthermore, sepsis patients with AKI had a higher level of hsa_Circ_0072463 compared to those without AKI. The sensitivity, specificity and AUC of hsa_Circ_0072463 were 78.8%, 87.9% and 0.866, respectively. Spearman's test indicated a noticeable positive correlation between plasma hsa_Circ_0072463 and serum creatinine in sepsis patients (r = 0.725). In summary, this study reveals that the mmu_Circ_26986/hsa_Circ_0072463 miRNA-29b-1-5p/PAK7 axis mediates septic AKI, and hsa_Circ_0072463 is a potential diagnostic marker for septic AKI.

Our recent investigation has indicated that the global deletion of MBD2 can mitigate the progression of AKI induced by VAN. Nevertheless, the role and regulatory mechanisms of proximal tubular MBD2 in this pathophysiological process have yet to be elucidated. Our preceding investigation revealed that autophagy played a crucial role in advancing AKI induced by VAN. Consequently, we postulated that MBD2 present in the proximal tubule could upregulate the autophagic process to expedite the onset of AKI. In the present study, we found for the first time that MBD2 mediated the autophagy production induced by VAN. Through the utilization of miRNA chip analysis, we have mechanistically demonstrated that MBD2 initiates the activation of miR-597-5p through promoter demethylation. This process leads to the suppression of S1PR1, which results in the induction of autophagy and apoptosis in renal tubular cells. Besides, PT-MBD2-KO reduced autophagy to attenuate VAN-induced AKI via regulation of the miR-597-5p/S1PR1 axis, which was reversed by rapamycin. Finally, the overexpression of MBD2 aggravated the diminished VAN-induced AKI in autophagy-deficient mice (PT-Atg7-KO). These data demonstrate that proximal tubular MBD2 facilitated the process of autophagy via the miR-597-5p/S1PR1 axis and subsequently instigated VAN-induced AKI through the induction of apoptosis. The potentiality of MBD2 being a target for AKI was established.

Purpose:To elucidate the etiology of infectious uveitis through the comprehensive analysis of keratic precipitates (KPs) using in vivo confocal microscopy (IVCM). Design:Cross-sectional, observational case series. Methods:This single-center, cross-sectional study was conducted at a tertiary care eye hospital from January 2021 to October 2023. It involved a detailed ophthalmologic evaluation of all subjects and included a total of 46 eyes from 36 subjects who were diagnosed with infectious uveitis. IVCM, specifically utilizing the HRT II Rostock corneal module, was employed to study the biomicroscopic morphology of KPs. The categorization of KPs was based on cell size, morphology, and reflection. Results:Cells of KPs were assessed for size, morphology, and reflection through in vivo confocal microscopy. Patients, ranging in age from 13 to 80 years (median 51 years), exhibited diverse morphologic forms of KPs. Neutrophil-dominated KPs with uniform size were predominantly observed in bacterial and fungal endophthalmitis cases (19/19, 100 %), accompanied by small numbers of mononuclear-macrophages in three eyes (3/19, 15.8 %). Viral uveitis cases displayed a broader array of immune cell types, including characteristic striated or dendritic cells in all eyes (27/27, 100 %). Lymphocytes were commonly present (24/27, 88.9 %), forming clusters in sixteen eyes and dispersed in the corneal endothelium below the midline in eight eyes. Neutrophil infiltration was notable in three cytomegalovirus-infected eyes (3/27, 11.1 %). A marked increase in sub-basal corneal epithelial Langhans cells was associated with viral uveitis. Conclusions:Neutrophil-dominated KPs strongly indicate endogenous bacterial or fungal endophthalmitis, while the presence of dendritic cells and lymphocytes in KPs is suggestive of viral uveitis. In vivo confocal microscopy emerges as a crucial tool for differentiating the etiologic diagnosis of infectious uveitis.

Retinal ganglion cells (RGCs) apoptosis is a vital manifestation of retinal ischemia/reperfusion (I/R) injury, yet the underlying mechanisms are not well understood. The contribution of long noncoding RNAs (lncRNAs) to this cellular process is currently being explored. Based on a lncRNA chip assay, we aimed to investigate the role of lncRNA uc007nnj.1 in the pathological process of ischemia-induced RGCs apoptosis. Hank’s balanced salt solution containing 10 µM antimycin A and 2 µM calcium ionophore for 2 h to construct an ischemic model in RGCs, and elevation of intraocular pressure to 120 mm Hg for 1 h was used to construct a mouse model of retinal I/R injury. In this study, lncRNA uc007nnj.1 was highly upregulated in response to I/R injury in RGCs and mouse retinas. In addition, lncRNA uc007nnj.1 knockdown reduced retinal neuronal cell apoptosis in vitro and in vivo and significantly improved retinal function. Mechanistically, the results demonstrated that lncRNA uc007nnj.1 acts as ceRNA competitively binding miR-155-5p, thereby enhancing the expression levels of Tle4, thus aggravating ischemia-related apoptosis in RGCs. Finally, our study identifies the lncRNA uc007nnj.1/miR-155-5p/Tle4 axis as a potential target for the prevention of I/R-induced retinal neuronal death.

A 35-year-old man with maternally inherited diabetes presented with blurring of vision in both eyes for 6 months. He previously received antituberculous therapy including ethambutol (EMB) for 2 years. Temporal disc pallor and central scotomas were noticed in both eyes. P100 latency was delayed in visual evoked potential bilaterally. In addition, an elevated blood lactate concentration was observed. Interestingly, although EMB's potential optic neuropathy toxicity was our first consideration, a m.3243A>G mutation of mitochondrial DNA was found in the blood. Herein, we reported a young patient carrying a novel Leber's hereditary optic neuropathy mutation who developed EMB-induced optic neuropathy.

A few studies suggested that CircRNAs were involved in the development of septic AKI. However，the role and regulation mechanism of CircRNA_35953 in septic AKI remains unclear. Here, we found that Circ_35953 was induced by LPS via activation of NF-κB signal in BUMPT cells. Functionally, Circ_35953 mediated the LPS induced the apoptosis in BUMPT cells. Moreover, we demonstrated that Circ_35953 sponged miR-7219-5p to upregulate the expression of HOOK3 and IGFBP7. Finally, we verified that knock down of Circ_35953 alleviated the progression of CLP-induced AKI via targeting the miR-7219-5p/HOOK3 and IGFBP7 signal. Collectively, the data suggested that Circ_35953 /miR-7219-5p/HOOK3 and IGFBP7 axis mediated the septic AKI, which also revealed a potential mechanism of septic AKI.

The pathogenesis of Diabetic kidney disease(DKD) involves pathological changes in both tubulo-interstitium and the glomerulus. Surprisingly, tubulo-interstitial fibrosis (TIF), does not develop significantly until the late stage of DKD. Here, it is demonstrated that PR domain-containing 16 (PRDM16) is a key to the low level of TIF in DKD. In the experiments, PRDM16 is upregulated in high glucose-treated renal tubular cells, DKD mouse kidneys, and renal biopsy of human DKD patients via activation of NF-κB signal pathway. High glucose-induced expression of fibrotic proteins in renal tubular cells is suppressed by PRDM16. Mechanistically, PRDM16 bound to the promotor region of Transient receptor potential ankyrin 1 (TRPA1) to transactivate its expression and then suppressed MAPK (P38, ERK1/2) activation and downstream expression of TGF-β1. Knockout of PRDM16 from kidney proximal tubules in mice blocked TRPA1 expression and enhanced MAPK activation, TGF-β1 production, TIF development, and DKD progression, whereas knock-in of PRDM16 has opposite effects. In addition, overexpression of PRDM16 or its induction by formononetin ameliorated renal dysfunction and fibrosis in db/db diabetic mice. Finally, the above finding are detected in renal biopsies of DKD patients. Together, these results unveil PRDM16/TRPA1 as the mechanism responsible for the low level of TIF in the early stage of DKD by suppressing and TGF-β1 expression.

DNA methylation plays a pivotal role in the progression of renal fibrosis. Methyl-CpG-binding domain protein 2 (MBD2), a protein reader of methylation, is involved in the development of acute kidney injury (AKI) caused by vancomycin. However, the role and mechanism of action of MBD2 in renal remain unclear. In this study, MBD2 mediated extracellular matrix (ECM) production induced by TGF-beta 1 in Boston University mouse proximal tubule (BUMPT) cells,and upregulated the expression EGR1 to promote ECM production in murine embryonic NIH 3T3 fibroblasts. ChIP analysis demonstrated that MBD2 physically interacted with the promoter region of the CpG islands of EGR1 genes and then activated their expression by inducing hypomethylation of the promoter region. In vivo, PT-MBD2-KO attenuated unilateral ureteral obstruction (UUO)-induced renal tubulointerstitial fibrosis via downregulation of EGR1, which was demonstrated by the downregulation of fibronectin (FN), collagen I and IV, alpha-SMA, and EGR1. Injection of MBD2-siRNA attenuated the UUO- and I/R-induced renal fibrosis. Those molecular changes were verified by biopsies from patients with obstructive nephropathy (OB). These data collectively demonstrated that inhibition of MBD2 reduces renal fibrosis via downregulating EGR1, which could be a target for treatment of fibrotic kidney disease.