Kidney Fibroblasts Research Articles

Blockade of neddylationthroughtargetedinhibition of DCN1 alleviates renal fibrosis.

Neddylationisa process of attachingneuronal precursor cell-expressed developmentally downregulated protein 8(NEDD8)tosubstratesfor the protein functionmodulationviaenzymatic cascades involvingNEDD8-activating enzyme (E1), NEDD8-conjugating enzyme (E2), andNEDD8 ligase (E3). Defective in cullin neddylation 1 (DCN1) serves as a co-E3 ligase, thatcan simultaneously bind E2 UBE2M and cullin proteins to stabilize the catalytic center of the Cullin-RingE3 ligase(CRL) complex, thereby promotingcullin neddylation. Neddylation is reported to be activatedin diversehuman diseases, and inhibition of protein neddylation has been regarded as a promising anticancer therapy. However, whether neddylation participatesin renal fibrosisand whether blockade of neddylationthrough targeted inhibitionof DCN1 play effectson renal fibrosisremainsunknown. In this study,aNEDD8 overexpressed plasmid, DCN1 small interfering RNAs(siRNAs), DCN1 specific inhibitor NAcM-OPT, human renal tubular epithelial cells (HK-2),rat kidney fibroblasts (NRK-49F),RNA-sequencing (RNA-seq), unilateral ureteral obstruction(UUO)andunilateralischemia-reperfusion injury(UIRI)mouse renal fibrosismodelswere used.Herein, wefirst showedthatneddylation was activatedin renal fibrosis. Neddylation blockade through DCN1deficiency alleviatedTGFβ1-inducedupregulation of fibronectin and α-SMAin HK-2 andNRK-49Fcells. Importantly, DCN1 inhibition attenuatedUUO andUIRI-induced mouse renal fibrosis. Further studies revealedthatDCN1 loss selectively inhibited cullin3 neddylation and inducedits substrate NRF2accumulation, thereby inhibiting TGFβ-Smad2/3 signalingpathway.Overall, blockadeof neddylation through targeted inhibition of DCN1 contributes to alleviating renal fibrosis in vitro and in vivo, which may constitutea noveltherapeutic strategyforrenalfibrosis.

SR9009 attenuates TGF-β1-induced renal fibrotic responses by inhibiting the NOX4/p38 signaling pathway in NRK-49F cells

The circadian clock protein reverse erythroblastosis virus (REV)-ERBα is implicated in the pathogenesis of various diseases, including cancer and myocardial infarction. Emerging evidence suggests that SR9009, an agonist of REV-ERBα, regulates multiple signaling molecules independent or dependent of REV-ERBα. However, the impact of SR9009 on renal fibrosis remains largely unevaluated. In this study, we investigated the effects of SR9009 on transforming growth factor (TGF)-β1-induced fibrotic responses and elucidated the mechanisms involved. Masson's trichome staining revealed that in the unilateral ureteral obstruction groups, there was a decrease in REV-ERBα expression, accompanied by increased levels of the profibrotic factor TGF-β1 and the fibrosis marker α-smooth muscle actin (α-SMA). REV-ERBα knockdown significantly increased α-SMA expression in NRK-49F cells. SR9009 significantly attenuated unilateral ureteral obstruction-induced fibrosis and TGF-β1-induced fibrotic responses in normal rat kidney fibroblasts (NRK-49F cells). Conversely, the REV-ERBα antagonist SR8278 did not affect TGF-β1-induced fibrotic responses. Mechanistic studies revealed that SR9009 significantly inhibited the phosphorylation of ERK and p38, concomitant with reduced α-SMA levels, suppressing TGF-β1-induced NADPH oxidase 4 (NOX4) mRNA expression in NRK-49F cells. Notably, SR9009 did not influence the expression of dual specificity phosphatase 4, which dephosphorylates MAPKs, including p38. Furthermore, REV-ERBα knockdown did not affect the ability of SR9009 to inhibit TGF-β1-induced fibrotic responses and NOX4 expression in NRK-49F cells. In conclusion, SR9009 exerts a protective role against renal fibrosis independent of REV-ERBα. Therefore, SR9009 is a promising therapeutic agent for the prevention and treatment of renal fibrosis associated with renal failure.

Sigma-1 Receptor as a Novel Therapeutic Target in Diabetic Kidney Disease.

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease. Current treatments for DKD do not halt renal injury progression, highlighting an urgent need for therapies targeting key disease mechanisms. Our previous studies demonstrated that activating the Sigma-1 receptor (S1R) with fluvoxamine (FLU) protects against acute kidney injury by inhibiting inflammation and ameliorating the effect of hypoxia. Based on these, we hypothesized that FLU might exert a similar protective effect in DKD. Diabetes was induced in male Wistar rats using streptozotocin, followed by a seven-week FLU treatment. Metabolic and renal parameters were assessed along with a histological analysis of glomerular damage and fibrosis. The effects of FLU on inflammation, hypoxia, and fibrosis were tested in human proximal tubular cells and normal rat kidney fibroblasts. FLU improved renal function and reduced glomerular damage and tubulointerstitial fibrosis. It also mitigated inflammation by reducing TLR4, IL6, and NFKB1 expressions and moderated the cellular response to tubular hypoxia. Additionally, FLU suppressed TGF-β1-induced fibrotic processes and fibroblast transformation. These findings suggest that S1R activation can slow DKD progression and protect renal function by modulating critical inflammatory, hypoxic, and fibrotic pathways; therefore, it might serve as a promising novel drug target for preventing DKD.

Synthesis and Cytotoxicity Evaluation of Novel C-3 Aminocarbamate Pregnenolone Derivatives

Cancer is one of the leading causes of death worldwide. There are many ongoing studies in the search for new treatments or drugs to combat cancer. Similarly, in this research, twelve 3-aminocarbamate pregnenolones (2a–2l) were designed, synthesized, and evaluated for their cytotoxicity against five cancer cell lines: Human hepatocellular carcinoma (HepG2), Human colon adenocarcinoma (HT-29), Human oral cavity carcinoma (KB), Human breast adenocarcinoma (MCF-7), Murine leukemia (P388), and one normal cell line, African green monkey kidney fibroblast (Vero), using the MTT assay. Notably, 3-aminobenzylcarbamate pregnenolone (2b), 3-diaminoheptylcarbamate pregnenolone (2f), and 3-diaminopropanolcarbamate derivative (2i) were the most potent against these cancer cell lines. Specifically, for P388 cell lines, these compounds were more potent than the positive control drug, vinblastine sulfate salt. Results from the SAR study demonstrated that the length of the alkyl chain of diaminocarbamate derivatives was crucial for their anticancer properties. These findings will be useful in the future research and development of anticancer drugs.

Assessment of molecular modulation by multifrequency electromagnetic pulses to preferably eradicate tumorigenic cells

Physics methods of cancer therapy are extensively used in clinical practice, but they are invasive and often confront undesired side effects. A fully new equipment that allows sustained emission of intense and time-controlled non-ionizing multifrequency electromagnetic pulse (MEMP), has been applied to eukaryotic cells in culture. The equipment discriminates the overall electronegative charge of the cell cultures, and its subsequent proportional emission may thereby become higher and lethal to cancer cells of generally high metabolic activity. In contrast, low tumorigenic cells would be much less affected. We tested the specificity and efficacy of the equipment against a collection of (i) highly tumorigenic cells of human (glioblastoma, cervical carcinoma, and skin) and mouse (colon adenocarcinoma) origin; (ii) cell lines of much lower tumorigenicity (non-human primate kidney and mouse fibroblasts), and (iii) primary porcine macrophages lacking tumorigenicity. Time and intensity control of the MEMP allowed progressive decay of viability fairly correlating to cell tumorigenicity, which was provoked by a proportional alteration of the cytoplasmic membrane permeability, cell cycle arrest at G2, and general collapse of the actin cytoskeleton to the perinuclear region. Correspondingly, these effects drastically inhibited the proliferative capacity of the most tumorigenic cells in clonogenic assays. Moreover, MEMP suppressed in a dose-dependent manner the tumorigenicity of retrovirally transduced luciferase expressing colon adenocarcinoma cells in xenografted immune-competent mice, as determined by tumor growth in a bioluminescence imaging system. Our results support MEMP as an anti-cancer non-invasive physical treatment of substantial specificity for tumorigenic cells with promising therapeutic potential in oncology.

Gucy1α1 specifically marks kidney, heart, lung and liver fibroblasts.

Fibrosis is a common outcome of numerous pathologies, including chronic kidney disease (CKD), a progressive renal function deterioration. Current approaches to target activated fibroblasts, key effector contributors to fibrotic tissue remodeling, lack specificity. Here, we report Gucy1α1 as a specific kidney fibroblast marker. Gucy1α1 levels significantly increased over the course of two clinically relevant murine CKD models and directly correlated with established fibrosis markers. Immunofluorescent (IF) imaging showed that Gucy1α1 comprehensively labelled cortical and medullary quiescent and activated fibroblasts in the control kidney and throughout injury progression, respectively. Unlike traditionally used markers platelet derived growth factor receptor beta (Pdgfrβ) and vimentin (Vim), Gucy1α1 did not overlap with off-target populations such as podocytes. Notably, Gucy1α1 labelled kidney fibroblasts in both male and female mice. Furthermore, we observed elevated GUCY1α1 expression in the human fibrotic kidney and lung. Studies in the murine models of cardiac and liver fibrosis revealed Gucy1α1 elevation in activated Pdgfrβ-, Vim- and alpha smooth muscle actin (αSma)-expressing fibroblasts paralleling injury progression and resolution. Overall, we demonstrate Gucy1α1 as an exclusive fibroblast marker in both sexes. Due to its multiorgan translational potential, GUCY1α1 might provide a novel promising strategy to specifically target and mechanistically examine fibroblasts.

Avian deltacoronaviruses encode fusion-associated small transmembrane proteins that can induce syncytia formation

Fusion-associated small transmembrane (FAST) proteins are nonstructural viral proteins that induce cell-cell fusion. FAST proteins, which previously were identified in the genomes of double-stranded RNA viruses, typically contain an acylated N-terminal ectodomain, central transmembrane domain, and C-terminal endodomain with a polybasic region. Using sequence homology and protein motif prediction, we identified accessory proteins in a subset of avian deltacoronaviruses as putative FAST proteins. Transient expression of thrush coronavirus NS7b or common moorhen coronavirus NS7a, but not night heron coronavirus NS7b, induced cell-cell fusion. Syncytia were detected in primate kidney epithelial cells or fibroblasts but not chicken embryo fibroblasts, and addition of an N-terminal FLAG peptide to the proteins ablated fusion activity. These findings suggest that multiple avian deltacoronaviruses, positive-sense RNA viruses, encode nonstructural proteins that can mediate cell-cell fusion and share features with known FAST proteins. Additional studies are needed to understand contributions of these proteins to deltacoronavirus biology.

Regulation of Kidney Fibroblast Functions by Palladin-MRTF Circuit in Response to TGF-β1

Regulation of Kidney Fibroblast Functions by Palladin-MRTF Circuit in Response to TGF-β1

Phytochemical Analysis and Evaluation of Antioxidant, Antidiabetic, and Anti-inflammatory Properties of Aegle marmelos and Its Validation in an In-Vitro Cell Model.

Persistent hyperglycemia significantly increases oxidative stress and inflammation resulting in multiple cellular and molecular alterations which further exacerbate the diabetes associated complications.Aegle marmelos (L.) Corrêais a medicinal plant used in the Indian system of medicine for treating various disorders including diabetes. However, studies on phytoconstituents and their pharmacological activity of this plant are limited. Therefore, we aimed to determine the phytochemical components, evaluate the antidiabetic activity, anti-inflammatory activity, and antioxidant activity ofA. marmelosleaf extract, and validate its mechanistic effects in an in vitro cell model. The qualitative and quantitative analysis of the different phytoconstituents in the extract was determined using standardized protocols. The antioxidant activity of the extract was evaluated by 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay and ferric reducing antioxidant power (FRAP) assay. The antidiabetic activity of the extract was evaluated by α-amylase inhibition and α-glucosidase inhibition assay. The anti-inflammatory activity was studied using an albumin denaturation assay. In addition, the pharmacological effect(s) of leaf extract was checked in the normal rat kidney fibroblast cells (NRK-49F) under high glucose conditions. Intracellular reactive oxygen species (ROS) generation was measured by fluorometry using fluorescence probe 2',7'-dichlorodihydrofluorescin diacetate (DCF-DA). mRNA expression of inflammatory markers including inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) was studied using real-time quantitative polymerase chain reaction (RT-qPCR). Cell migration was studied using cell scratch assay. Statistical analysis was performed using GraphPad Prism version 8.0. The phytochemical analysis ofA. marmelosleaf extract revealed the presence of alkaloids, phenols, flavonoids, and saponins. The extract showed higher antioxidant activity in the DPPH (IC50=258.21 µg/mL) and FRAP assay (IC50=293.83 µg/mL). The extract exhibited prominent antidiabetic activity by inhibiting enzymes α-Amylase (IC50=73.2 µg/mL) and α-glucosidase (IC50=43.9 µg/mL). In addition, the extract showed effective anti-inflammatory activity by significantly inhibiting the denaturation of egg albumin (IC50=102.8 µg/mL). Further, the leaf extract significantly decreased the high glucose-induced ROS generation as well as inflammatory markers in rat fibroblast cell lines in a dose-dependent manner. Additionally, high glucose-induced cell migration as the measure of cell injury was effectively reduced by the extract treatment. A. marmelosleafextract was quantified to possess a substantial amount of important phytoconstituents that have promising pharmacological properties. Besides showing antidiabetic activity, the extract significantly combats the high glucose-induced ROS generation, inflammatory markers expressions, and cell migration. Further, in-depth studies and clinical trials are warranted so as to position these traditional remedies for the treatment of metabolic disorders.

Organotin(IV) compounds loaded in thermo- and pH-responsive smart polymeric nanocarriers based on poly(DEGMA-co-OEGMA)-b-poly(DEAEM) a drug releasing system and in vitro anticancer activity

Nanocarriers in cancer treatment are important for transport and release of insoluble drugs. In this work, block thermo- and pH-responsive copolymers based on poly(di(ethylene glycol) methyl ether methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate) (PDO) and poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEA) were tested. At pH 7.4 and 37 °C, the title polymers formed micelles which were used for the loading and release of diorganotin(IV) complexes (LSnR2), where L is a Schiff base ligand and R = n-butyl (LSnBu2) or cyclohexyl (LSnCy2). Results revealed that the PDO-b-PDE block copolymers could enhance the solubility of LSnR2(IV) compounds in PBS at pH = 7.4, resulting in good loading capacity (%DLC) and loading efficiency (%DLE), and better release performance (pH-dependent and T-dependent) than the free compound. In vitro cytotoxic activity was evaluated by the sulforhodamine B (SRB) assay against a normal cell line, African green monkey kidney fibroblast (COS-7) and seven human cancer cell lines prostate (PC-3), leukemia (K-562), colon (HCT-15), lung (SKLU-1), central nervous system glia (U-251), breast Strogen receptor-positive (MCF-7) and breast hormone-independent (MDA-MB-231). The non-loaded block copolymers were non-cytotoxic, but the loaded ones showed high cell growth inhibition against human cancer cell lines. Results confirmed that these temperature and pH-sensitive polymeric systems are excellent candidates for the loading and release of potential metallodrugs, such as LSnR2, against diverse types of cancers.

Evaluation of the novel ALK5 inhibitor EW-7197 on therapeutic efficacy in renal fibrosis using a three-dimensional chip model.

EW-7197, a potent oral ALK5 inhibitor, was assessed for its impact on transforming growth factor beta 1 (TGF-β1)-induced fibrosis in a three-dimensional (3D) renal fibrosis-on-a-chip and a mouse model. The evaluation included tubular epithelial-mesenchymal transition, angiogenesis, and inflammatory cytokine expression. In a 3D renal fibrosis-on-a-chip model, three cell types (kidney fibroblasts, human proximal tubular cell line, and human umbilical vein endothelial cells) were cultured and treated with TGF-β1 and EW-7197. Expression of alpha smooth muscle actin (α-SMA) and keratin 8 (KRT-8) was assessed, angiogenesis was observed via confocal microscopy, and cytokine levels were measured using real-time polymerase chain reaction, immunoassay, and enzyme-linked immunosorbent assay. In a cisplatin-induced renal fibrosis mouse model, blood urea nitrogen levels, TGF-β, and Smad 2/3 were determined, and renal fibrosis was assessed with Masson's trichrome stain. The α-SMA expression was significantly lower in the EW-7197 group than in the TGF-β fibrosis group. TGF-β decreased the expression of the epithelial marker KRT-8, an effect that was reversed by EW-7197 and SB431542. In the TGF-β-induced fibrosis model, the length of the thick vessels was reduced, and the diameter of both thick and thin vessels was decreased, but EW-7197 reversed these effects. EW-7197 significantly reduced the messenger RNA expression of TGF-β and increased the levels of vascular endothelial growth factor receptor 2, interleukin (IL)-10, and IL-6. EW-7197 reduced the levels of secretory cytokines TGF-β1, TGF-β3, IL-1β. In the cisplatin-induced renal fibrosis mouse model, EW-7197 reduced renal fibrosis by down-regulating TGF-β signaling. EW-7197 attenuated the TGF-β1-induced fibrotic cellular response in the 3D chip model and animal model. These findings indicate the potential effect of EW-7197 in attenuating renal fibrosis.

Calorie restriction exacerbates folic acid-induced kidney fibrosis by altering mitochondria metabolism

Calorie restriction (CR) is known to confer health benefits, including longevity and disease prevention. Although CR is promising in preventing chronic kidney disease (CKD), its potential impact on the progression of kidney fibrosis from acute kidney injury (AKI) to CKD remains unclear. Here, we present evidence that CR exacerbates renal damage in a mouse model of folic acid (FA)-induced renal fibrosis by altering mitochondrial metabolism and inflammation. Mice subjected to CR (60% of ad libitum) for three days were subjected to high dose of FA (250 mg/kg) injection and maintained under CR for an additional week before being sacrificed. Biochemical analyses showed that CR mice exhibited increased kidney injury and fibrosis. RNA sequencing analysis demonstrated decreased electron transport and oxidative phosphorylation (OXPHOS) in CR kidneys with injury, heightened inflammatory, and fibrotic responses. CR significantly decreased OXPHOS gene and protein levels and reduced β-oxidation-associated proteins in the kidney. To determine whether defects in mitochondrial metabolism is associated with inflammation in the kidney, further in vitro experiments were performed. NRK52E kidney epithelial cells were treated with antimycin A to induce mitochondrial damage. Antimycin A treatment significantly increased chemokine expression via a STING-dependent pathway. Serum restriction in NRK49F kidney fibroblasts was observed to enhance the fibrotic response induced by TGFβ under in vitro conditions. In summary, our results indicate that CR exacerbates fibrosis and inflammatory responses in the kidney by altering mitochondrial metabolism, highlighting the importance of adequate energy supply for an effective response to AKI and fibrosis development.

Activation of Yes-Associated Protein Is Indispensable for Transformation of Kidney Fibroblasts into Myofibroblasts during Repeated Administration of Cisplatin.

Cisplatin is a potent chemotherapy medication that is used to treat various types of cancer. However, it can cause nephrotoxic side effects, which lead to acute kidney injury (AKI) and subsequent chronic kidney disease (CKD). Although a clinically relevant in vitro model of CKD induced by repeated administration of low-dose cisplatin (RAC) has been established, its underlying mechanisms remain poorly understood. Here, we compared single administration of high-dose cisplatin (SAC) to repeated administration of low-dose cisplatin (RAC) in myofibroblast transformation and cellular morphology in a normal rat kidney fibroblast NRK-49F cell line. RAC instead of SAC transformed the fibroblasts into myofibroblasts as determined by α-smooth muscle actin, enlarged cell size as represented by F-actin staining, and increased cell flattening as expressed by the semidiameter ratio of attached cells to floated cells. Those phenomena, as well as cellular senescence, were significantly detected from the time right before the second administration of cisplatin. Interestingly, inhibition of the interaction between Yes-associated protein (YAP) and the transcriptional enhanced associated domain (TEAD) using Verteporfin remarkedly reduced cell size, cellular senescence, and myofibroblast transformation during RAC. These findings collectively suggest that YAP activation is indispensable for cellular hypertrophy, senescence, and myofibroblast transformation during RAC in kidney fibroblasts.

Gucy1α1 specifically marks kidney, heart, lung and liver fibroblasts.

Fibrosis is a common outcome of numerous pathologies, including chronic kidney disease (CKD), a progressive renal function deterioration. Current approaches to target activated fibroblasts, key effector contributors to fibrotic tissue remodeling, lack specificity. Here, we report Gucy1α1 as a specific kidney fibroblast marker. Gucy1α1 levels significantly increased over the course of two clinically relevant murine CKD models and directly correlated with established fibrosis markers. Immunofluorescent (IF) imaging showed that Gucy1α1 comprehensively labelled cortical and medullary quiescent and activated fibroblasts in the control kidney and throughout injury progression, respectively. Unlike traditionally used markers platelet derived growth factor receptor beta (Pdgfrβ) and vimentin (Vim), Gucy1α1 did not overlap with off-target populations such as podocytes. Notably, Gucy1α1 labelled kidney fibroblasts in both male and female mice. Furthermore, we observed elevated GUCY1α1 expression in the human fibrotic kidney and lung. Studies in the murine models of cardiac and liver fibrosis revealed Gucy1α1 elevation in activated Pdgfrβ-, Vim- and alpha smooth muscle actin (αSma)-expressing fibroblasts paralleling injury progression and resolution. Overall, we demonstrate Gucy1α1 as an exclusive fibroblast marker in both sexes. Due to its multiorgan translational potential, GUCY1α1 might provide a novel promising strategy to specifically target and mechanistically examine fibroblasts.

3D printed subcutaneous implant for prolonged delivery of tenofovir with desired release capability, biocompatibility, and viability

This study introduced a progressive approach to address the challenges associated with drug delivery in hepatitis B by developing a 3D printed subcutaneous implant. The implant, composed of a polymer-reinforced bovine serum albumin hydrogel crosslinked with glutaraldehyde, exhibited shear thinning and thixotropic behavior. This allows it to undergo transformation into an implant using a semisolid extrusion-based 3D printing technique. Thorough analysis encompassing physical, thermal, and spectroscopy assessments ensured thermal and chemical stability of the implant. Scanning electron microscopy revealed the highly porous microstructures of the hydrogel implant, enhancing its suitability for drug encapsulation. Swelling study showed only 7.88 % swelling of the implant after 28 days, suggesting restricted water movement into the implant matrix, leading to a gradual release of the encapsulated drug. The biodegradable nature of the implant was confirmed using an enzyme degradation study. Notably, the hydrogel implant exhibited sustained release of tenofovir of approximately 63 % over a 28-day period, presenting a promising avenue for prolonged therapeutic interventions in both hepatitis B. Furthermore, the crosslinked hydrogel was found to be cytocompatible in human kidney and dermal fibroblast cells. Overall, this work signifies a notable advancement in implantable drug delivery systems utilizing both hydrogel and the emerging 3D printing technique, offering a potential solution for sustained and localized treatment of chronic viral infections.

Dynamically visualizing profibrotic maladaptive repair after acute kidney injury by fibroblast activation protein imaging

A major challenge in prevention and early treatment of organ fibrosis is the lack of valuable tools to assess the evolving profibrotic maladaptive repair after injury invivo in a non-invasive way. Here, using acute kidney injury (AKI) as an example, we tested the utility of fibroblast activation protein (FAP) imaging for dynamic assessment of maladaptive repair after injury. The temporospatial pattern of kidney FAP expression after injury was first characterized. Single-cell RNA sequencing and immunostaining analysis of patient biopsies were combined to show that FAP was specifically upregulated in kidney fibroblasts after AKI and was associated with fibroblast activation and chronic kidney disease (CKD) progression. This was corroborated in AKI mouse models, where a sustained and exaggerated kidney FAP upregulation was coupled to persistent fibroblast activation and a fibrotic outcome, linking kidney FAP level to post-insult maladaptive repair. Furthermore, using positron emission tomography (PET)/CT scanning with FAP-inhibitor tracers ([18F]FAPI-42, [18F]FAPT) targeting FAP, we demonstrated the feasibility of non-invasively tracking of maladaptive repair evolution toward kidney fibrosis. Importantly, a sustained increase in kidney [18F]FAPT (less hepatobiliary metabolized than [18F]FAPI-42) uptake reflected persistent kidney upregulation of FAP and characterized maladaptive repair after AKI. Kidney [18F]FAPT uptake at hour 2-day 7 correlated with kidney fibrosis 14 days after AKI. Similar changes in [18F]FAPI-42 PET/CT imaging were observed in patients with AKI and CKD progression. Thus, persistent kidney FAP upregulation after AKI was associated with maladaptive repair and a fibrotic outcome. Hence, FAP-specific PET/CT imaging enables dynamic visualization of maladaptive repair after AKI and prediction of kidney fibrosis within a clinically actionable window.

Transcription factor Twist1 drives fibroblast activation to promote kidney fibrosis via signaling proteins Prrx1/TNC

The transcription factor Twist1 plays a vital role in normal development in many tissue systems and continues to be important throughout life. However, inappropriate Twist1 activity has been associated with kidney injury and fibrosis, though the underlying mechanisms involved remain incomplete. Here, we explored the role of Twist1 in regulating fibroblast behaviors and the development kidney fibrosis. Initially Twist1 protein and activity was found to be markedly increased within interstitial myofibroblasts in fibrotic kidneys in both humans and rodents. Treatment of rat kidney interstitial fibroblasts with transforming growth factor-β1 (a profibrotic factor) also induced Twist1 expression in vitro. Gain- and loss-of-function experiments supported that Twist1 signaling was responsible for transforming growth factor-β1-induced fibroblast activation and fetal bovine serum-induced fibroblast proliferation. Mechanistically, Twist1 protein promoted kidney fibroblast activation by driving the expression of downstream signaling proteins, Prrx1 and TNC. Twist1 directly enhanced binding to the promoter of Prrx1 but not TNC, whereas the promoter of TNC was directly bound by Prrx1. Finally, mice with fibroblast-specific deletion of Twist1 exhibited less Prrx1 and TNC protein abundance, interstitial extracellular matrix deposition and kidney inflammation in both the unilateral ureteral obstruction and ischemic-reperfusion injury-induced kidney fibrotic models. Inhibition of Twist1 signaling with Harmine, a β-carboline alkaloid, improved extracellular matrix deposition in both injury models. Thus, our results suggest that Twist1 signaling promotes the activation and proliferation of kidney fibroblasts, contributing to the development of interstitial fibrosis, offering a potential therapeutic target for chronic kidney disease.

Expression of the Discoidin Domain Receptor Family Depended on Glucose and Their High Expression in Arterial Tissues in the Rat Model of Type 2 Diabetes.

The active form of discoidin domain receptors (DDRs) is expressed in cell surface and regulated post-translationally by glucose. The DDR2 and DDR1 transfected in HEK293 cells were expressed mainly in their active forms with sizes of 130 and 120 kDa, respectively. DDRs were observed predominantly as 100 kDa proteins in glucose-depleted culture conditions. However, transfection of endothelial growth factor receptor (EGFR) in HEK293 cells resulted in the expression of only one form regardless of glucose concentration. Vascular smooth muscle cells, HT1080s, and MDA-MB-231 cancer cells expressed DDRs in their active forms in high glucose concentrations, which did not occur with EGFR. In diabetic rats, DDRs were expressed at high levels in arterial tissue but EGFR was not highly expressed. Taken together, these results suggest that DDRs expression depends on glucose concentration it may cooperate in the development of atherosclerosis and kidney fibroblasts, promoting nephropathy in diabetic rats.

Chemical constituents of Lasiodiplodia theobromae BPPCA 144, an endophytic fungus, isolated from Aglaia argentea Blume

Endophytic fungi from Aglaia argentea have indicated the prospective to produce secondary metabolites with unique activities, making them promising candidates for anticancer drug development. This study aimed to investigate the secondary metabolites produced by Lasiodiplodia theobromae BPPCA144, isolated from A. argentea. L. theobromae BPPCA144 was found to produce seven compounds: 2-phenylethanol (1), tyrosol (2), 2-(4-hydroxyphenyl)acetic acid (3), (-)-mellein (4), colletopeptide B (5), botryorhodine A (6), and (4R*,6R*)-4-hydroxy-6-n-propyl-1-oxacyclohexan-2-one (7). These compounds were isolated using vacuum liquid and radial chromatography, and their chemical structures were elucidated through 1D-NMR, 2D-NMR analysis, compared with previously reported spectral data. Notably, compounds (5) and (7) were identified as original from L. theobromae. Among the tested compounds, compound (2) exhibited the strongest activity against MCF-7 breast cancer cells. However, compounds (1, 3, 5 and 7) showed insufficient activity against CV-1 cell lines (normal kidney fibroblast cells).

#2027 Activation of histone deacetylase-1 in fibroblasts and pericytes induces renal interstitial fibrosis after ischemia-reperfusion injury

Abstract Background and Aims Following an acute kidney ischemic event the chromatin remodelling enzyme, histone deacetylase-1 (HDAC1), is activated in many cell types of the kidney including fibroblasts and pericytes. During kidney injury, the fibroblasts/pericytes differentiate into the myofibroblasts and produce extracellular matrix that can lead to a permanent decline in kidney function. Pharmacological inhibition of HDACs can attenuate ischemia-reperfusion-injury (IRI) mediated interstitial fibrosis. The hypothesis of this study was that fibroblast/pericyte HDAC1 activation promotes myofibroblast differentiation and interstitial fibrosis. Method Tamoxifen inducible, fibroblast/pericyte HDAC1 knockout (KO) mice (HDAC1Fl/Fl; Col1a2-CreEr) and littermate controls (HDAC1Fl/Fl) were used. Male and female mice were given tamoxifen by ip at 8-10 weeks of age and IRI or sham surgery completed after a 2-week tamoxifen washout period. A mild, 18 min, bilateral, warm IRI model was used, and samples collected over 4 weeks. Glomerular filtration rate (GFR) was assessed using transdermal FITC-Sinistrin clearance. In vitro experiments with kidney fibroblast cells (NRK49F) overexpressing empty vector or HDAC1 were used for RNA-sequencing to determine the HDAC1-dependent myofibroblast transcriptome. Results We confirmed that HDAC1 was knockdown in myofibroblast cells from KO mice with co-localization of HDAC1 and PDGFRβ or α-smooth muscle actin in the kidneys of IRI mice. Twenty-four hours post-surgery, all IRI mice exhibited 2-3 times increase in serum creatinine and a ∼50% reduction in GFR compared to sham mice (control IRI = 513 ± 129 μl /min/100 g body mass, control sham = 1010 ± 218, n = 4-5, p = 0.02; KO IRI = 529 ± 116, KO sham = 1187 ± 59 μl/min/100 g body mass, n = 4-5, p = 0.004). Subsequent GFR measurements over the next 4 weeks showed a gradual recovery of renal function of IRI mice starting at week 2 and fully restored to sham values by week 4. However, the male control IRI mice had significant focal interstitial fibrosis 2- and 4-weeks post injury (4-week data: sham = 0.3 ± 0.09 % of cortical area, IRI = 1.2 ± 0.2%, n = 6/group, p = 0.0011) but this was attenuated in the KO male IRI mice (sham = 0.4 ± 0.07% n = 4, IRI = 0.5 ± 0.1%, n = 7, p = 0.93). The female mice, regardless of genotype, had very little kidney damage or interstitial fibrosis at 4 weeks. Transcriptomes of NRK49F cells overexpressing HDAC1 had an upregulation of 55 genes related to pro-inflammatory cytokines and tumour necrosis factor signalling and downregulation of 367 genes related to cell junctions, cytoskeleton proteins, and cell adhesion compared to the empty vector control cells. Fibroblast proliferation rates were not statistically different among the groups, suggesting HDAC1 does not affect myofibroblast proliferation but rather pro-inflammatory gene expression. Conclusion In male mice, fibroblast/pericyte activation of HDAC1 leads to the production of pro-inflammatory cytokines that we predict will lead to immune cell infiltration and crosstalk that leads to the excessive production of interstitial fibrosis following IRI.