Gut bacteria are essential for development of an invasive bark beetle by regulating glucose transport.

Insects and their gut bacteria form a tight and beneficial relationship, especially in utilization of host nutrients. The red turpentine beetle (RTB), a destructive and invasive pine pest, employs mutualistic microbes to facilitate its invasion success. However, the molecular mechanism underlying the utilization of nutrients remains unknown. In this study, we found that gut bacteria are crucial for the utilization of D-glucose, a main carbon source for RTB development. Downstream assays revealed that gut bacteria-induced gut hypoxia and the secretion of riboflavin are responsible for RTB development by regulating D-glucose transport via the activation of a hypoxia-induced transcription factor 1 (Hif-1α). Further functional investigations confirmed that Hif-1α mediates glucose transport by direct upregulation of two glucose transporters (ST10 and ST27), thereby promoting RTB development. Our findings reveal how gut bacteria regulate the development of RTB, and promote our understanding of the mutualistic relationship of animals and their gut bacteria.

Vitexin attenuates chronic kidney disease by inhibiting renal tubular epithelial cell ferroptosis via NRF2 activation.

BACKGROUND: Chronic kidney disease (CKD) involves a variety of pathological processes, and ferroptosis plays a vital role in CKD progression. Targeting ferroptosis is a promising strategy for the treatment of CKD. However, inhibitors of ferroptosis have not been used in the clinical treatment of CKD. Vitexin is a natural flavonoid with many biological activities and protective effects against various diseases. However, whether vitexin can prevent the progression of CKD is not known. METHODS: In vivo, the effect of vitexin on CKD was evaluated by using mouse models of unilateral ureteral obstruction (UUO) and unilateral ischemia-reperfusion (UIR). Western blotting, Sirius red staining and transmission electron microscopy were used to analyze renal tubular injury, interstitial fibrosis, and inflammation in the kidneys of UUO and UIR mice. In vitro, CCK8 assays and lipid peroxidation assays were performed to analyze cell viability and lipid peroxidation in human renal tubular epithelial cells (HK2 cells) induced by erastin. The activation of renal fibroblasts (NRK-49 F cells) was also analyzed. Additionally, an in-silico protein-drug docking model and coimmunoprecipitation were performed to determine the direct substrate of vitexin. RESULTS: In vivo, vitexin treatment significantly ameliorated renal tubular injury, interstitial fibrosis, and inflammation in the kidneys of UUO and UIR mice. Additionally, our results showed that vitexin significantly attenuated UUO- and UIR-induced ferroptosis in renal tubular epithelial cells by upregulating glutathione peroxidase 4 (GPX4) protein levels and inhibiting lipid peroxidation in mouse kidneys. In vitro, treatment with vitexin inhibited erastin-induced ferroptosis in HK2 cells. Moreover, vitexin inhibited the expression of collagen I and α-SMA (alpha-smooth muscle actin) in NRK-49 F cells induced by the supernatant of erastin-treated HK2 cells. Mechanistically, our results suggested that vitexin could activate the NRF2/heme oxygenase-1 (HO-1) pathway by inhibiting the KEAP1- and ubiquitination-mediated degradation of NRF2, thereby increasing the expression of GPX4, and further inhibiting lipid peroxidation and ferroptosis. Additionally, knockout of NRF2 greatly inhibited the antiferroptotic effects of vitexin. CONCLUSIONS: Taken together, our results indicate that vitexin can protect against renal tubular epithelial cell ferroptosis in CKD by activating the KEAP1/NRF2/HO-1 pathway and is a promising drug to treat CKD.

Trehalose attenuates renal ischemia-reperfusion injury by enhancing autophagy and inhibiting oxidative stress and inflammation.

Renal ischemia-reperfusion (IR) injury is one of the most common acute kidney injuries, but there is still a lack of effective treatment in the clinical setting. Trehalose (Tre), a natural disaccharide, has been demonstrated to protect against oxidative stress, inflammation, and apoptosis. However, whether it could protect against IR-induced renal injury needs to be investigated. In an in vivo experiment, C57BL/6J mice were pretreated with or without Tre (2 g/kg) through a daily single intraperitoneal injection from 3 days before renal IR surgery. Renal function, apoptosis, oxidative stress, and inflammation were analyzed to evaluate kidney injury. In an in vitro experiment, mouse proximal tubular cells were treated with or without Tre under a hypoxia/reoxygenation condition. Western blot analysis, autophagy flux detection, and apoptosis assay were performed to evaluate the level of autophagy and antiapoptotic effect of Tre. The in vivo results showed that the renal damage induced by IR was ameliorated by Tre treatment, as renal histology and renal function were improved and the enhanced protein levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin were blocked. Moreover, autophagy was activated by Tre pretreatment along with inhibition of the IR injury-induced apoptosis, oxidative stress, and inflammation. The in vitro results showed that Tre treatment activated autophagy and protected against hypoxia/reoxygenation-induced tubular cell apoptosis and oxidative stress. Our results demonstrated that Tre protects against IR-induced renal injury, possibly by enhancing autophagy and blocking oxidative stress, inflammation, and apoptosis, suggesting its potential use for the clinical treatment of renal IR injury.

Inhibition of Mitochondrial Complex I Aggravates Folic Acid-Induced Acute Kidney Injury.

BACKGROUND: Some researches revealed that mitochondrial dysfunction is associated with various kidney injury. However, the role of mitochondrial dysfunction in the pathogenesis of acute kidney injury (AKI) still needs evidence. METHODS: We evaluated the effect of mitochondrial complex I inhibitor rotenone on folic acid (FA)-induced AKI in mice. RESULTS: Strikingly, the mice pretreated with rotenone at a dose of 200 ppm in food showed exacerbated kidney injury as shown by higher levels of blood urea nitrogen and creatinine compared with FA alone group. Meanwhile, both renal tubular injury score and the expression of renal tubular injury marker neutrophil gelatinase-associated lipocalin were further elevated in rotenone-pretreated mice, suggesting the deteriorated renal tubular injury. Moreover, the decrements of mitochondrial DNA copy number and the expressions of mitochondrial Cytochrome c oxidase subunit 1, mitochondrial NADH dehydrogenase subunit 1, and mitochondria-specific superoxide dismutase (SOD2) in the kidneys of FA-treated mice were further reduced in rotenone-pretreated mice, indicating the aggravated mitochondrial damage. In parallel with the SOD2 reduction, the oxidative stress markers of malondialdehyde and HO-1 displayed greater increment in AKI mice with rotenone pretreatment in line with the deteriorated apoptotic response and inflammation. CONCLUSION: Our results suggested that the inhibition of mitochondrial complex I activity aggravated renal tubular injury, mitochondrial damage, oxidative stress, cell apoptosis, and inflammation in FA-induced AKI.

Hypoxia-inducible factor prolyl hydroxylase inhibitor roxadustat (FG-4592) protects against cisplatin-induced acute kidney injury.

Renal hypoxia occurs in acute kidney injury (AKI) of various etiologies. Activation of hypoxia-inducible transcription factor (HIF) has been identified as an important mechanism of cellular adaptation to low oxygen. Preconditional HIF activation protects against AKI, suggesting a new approach in AKI treatment. HIF is degraded under normoxic conditions mediated by oxygen-dependent hydroxylation of specific prolyl residues of the regulative α-subunits by HIF prolyl hydroxylases (PHD). FG-4592 is a novel, orally active, small-molecule HIF PHD inhibitor for the treatment of anemia in patients with chronic kidney disease (CKD). The current study aimed to evaluate the effect of FG-4592 (Roxadustat) on cis-diamminedichloroplatinum (cisplatin)-induced kidney injury. In mice, pretreatment with FG-4592 markedly ameliorated cisplatin-induced kidney injury as shown by the improved renal function (blood urea nitrogen (BUN), serum creatinine (Scr), and cystatin C) and kidney morphology (periodic acid-Schiff (PAS) staining) in line with a robust blockade of renal tubular injury markers of kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Meanwhile, the renal apoptosis and inflammation induced by cisplatin were also strikingly attenuated in FG-4592-treated mice. Along with the protective effects shown above, FG-4592 pretreatment strongly enhanced HIF-1α in tubular cells, as well as the expressions of HIF target genes. FG-4592 alone did not affect the renal function and morphology in mice. In vitro, FG-4592 treatment significantly up-regulated HIF-1α and protected the tubular cells against cisplatin-induced apoptosis. In summary, FG-4592 treatment remarkably ameliorated the cisplatin-induced kidney injury possibly through the stabilization of HIF. Thus, besides the role in treating CKD anemia, the clinical use of FG-4592 also could be extended to AKI.

Effects of novel brominated flame retardant TBPH and its metabolite TBMEHP on human vascular endothelial cells: Implication for human health risks.

As a replacement for polybrominated diphenyl ethers, bis-(2-ethylhexyl) tetrabromophthalate (TBPH) is widely used as a novel flame retardant and has been detected in many environmental matrix including human blood. TBPH can be metabolized into mono-(2-ethyhexyl) tetrabromophthalate (TBMEHP) by carboxylesterase. However, their adverse effects on human vascular endothelium and their potential impacts on human cardiovascular disease are unknown. In this study, their adverse effects and associated molecular mechanisms on human vascular endothelial cells (HUVECs) were investigated. A concentration-dependent inhibition on HUVECs' viability and growth was observed for TBMEHP but not for TBPH. TBMEHP induced a marked G0/G1 cell cycle arrest and robust cell apoptosis at 1µg/mL by inducing expression of p53, GADD45α and cyclin dependent kinase (CDK) inhibitors (p21and p27) while suppressing the expression of cyclin D1, CDK2, CDK6, and Bcl-2. Unlike TBMEHP, TBPH caused early apoptosis after G2/M phase arrest only at 10µg/mL via up-regulation of p21 and down-regulation of CDK2 and CDK4. TBMEHP decreased mitochondrial membrane potential and increased caspase-3 activity at 1µg/mL, suggesting that activation of p53 and mitochondrial pathway were involved in the cell apoptosis. The data showed that TBPH and TBMEHP induced different cell cycle arrest and apoptosis through different molecular mechanisms with much higher toxicity for TBMEHP. Our study implies that the metabolites of TBPH, possibly other novel brominated flame retardants, may be of potential concern for human cardiovascular disease.

Elemental Concentrations in Urban Green Stormwater Infrastructure Soils.

Green stormwater infrastructure (GSI) is designed to capture stormwater for infiltration, detention, evapotranspiration, or reuse. Soils play a key role in stormwater interception at these facilities. It is important to assess whether contamination is occurring in GSI soils because urban stormwater drainage areas often accumulate elements of concern. Soil contamination could affect hydrologic and ecosystem functions. Maintenance workers and the public may also be exposed to GSI soils. We investigated soil elemental concentrations, categorized as macro- and micronutrients, heavy metals, and other elements, at 59 GSI sites in the city of Philadelphia. Non-GSI soil samples 3 to 5 m upland of GSI sites were used for comparison. We evaluated differences in elemental composition in GSI and non-GSI soils; the comparisons were corrected for the age of GSI facility, underlying soil type, street drainage, and surrounding land use. Concentrations of Ca and I were greater than background levels at GSI sites. Although GSI facilities appear to accumulate Ca and I, these elements do not pose a significant human health risk. Elements of concern to human health, including Cd, Hg, and Pb, were either no different or were lower in GSI soils compared with non-GSI soils. However, mean values found across GSI sites were up to four times greater than soil cleanup objectives for residential use.

Use of 16S rRNA Gene-Targeted Group-Specific Primers for Real-Time PCR Analysis of Predominant Bacteria in Mouse Feces.

Mouse models are widely used for studying gastrointestinal (GI) tract-related diseases. It is necessary and important to develop a new set of primers to monitor the mouse gut microbiota. In this study, 16S rRNA gene-targeted group-specific primers for Firmicutes, Actinobacteria, Bacteroidetes, Deferribacteres, "Candidatus Saccharibacteria," Verrucomicrobia, Tenericutes, and Proteobacteria were designed and validated for quantification of the predominant bacterial species in mouse feces by real-time PCR. After confirmation of their accuracy and specificity by high-throughput sequencing technologies, these primers were applied to quantify the changes in the fecal samples from a trinitrobenzene sulfonic acid-induced colitis mouse model. Our results showed that this approach efficiently predicted the occurrence of colitis, such as spontaneous chronic inflammatory bowel disease in transgenic mice. The set of primers developed in this study provides a simple and affordable method to monitor changes in the intestinal microbiota at the phylum level.

Tiliroside attenuates acute kidney injury by inhibiting ferroptosis through the disruption of NRF2-KEAP1 interaction.

BACKGROUND: Ferroptosis, an iron-dependent process that regulates cell death. Emerging evidences suggest that ferroptosis induces acute kidney injury (AKI) progression, and inhibiting ferroptosis provides an effect strategy for AKI treatment. The disruption of the NRF2-KEAP1 protein to protein interaction (PPI) induces NRF2 activation, which provides a promising strategy that can identify new ferroptosis inhibitors. A previous study revealed that tiliroside, a glycosidic flavonoid extracted from Edgeworthia chrysantha Lindl (buds), has anti-neuroinflammatory and neuroprotective effects via NRF2 activation. However, the mechanism through which tiliroside activates NRF2 is unknown, and it remains unclear whether it has protective effects against AKI. PURPOSE: To investigate whether tiliroside has protective effects against AKI in mice and the associated mechanisms. METHODS: Possible tiliroside substrates were analyzed using molecular docking. Cisplatin- and ischemia-reperfusion injury (IRI)-induced AKI mouse models and HK2 cells model were constructed to evaluate the protective effects of tiliroside. CRISPR/Cas9 mediated NRF2 knockout HK2 cells were used to verify whether NRF2 mediates tiliroside protective effects. RESULTS: In vivo, our results showed that tiliroside treatment preserved kidney functions in AKI mice models, as showed by lower levels of serum creatinine (SCr), blood urea nitrogen (BUN), and renal injury markers, including neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1), compared with the mice in control groups. In vitro, tiliroside treatment greatly ameliorated cisplatin-induced ferroptosis through NRF2 activation in cultured HK2 cells, as evidenced by the protective effects of tiliroside being greatly blunted after the knockout of NRF2 in HK2 cells. Mechanistic studies indicated that tiliroside promoted NRF2/GPX4 pathway activation and ferroptosis inhibition, perhaps via the disruption of the NRF2-KEAP1 PPI. CONCLUSION: Together, our results demonstrate that tiliroside may serve as a NRF2-KEAP1 PPI inhibitor and prevents ferroptosis-induced AKI, indicating its potential for clinical AKI treatment.

G-Protein Coupled Receptor Gpr-1 Is Important for the Growth and Nutritional Metabolism of an Invasive Bark Beetle Symbiont Fungi Leptographium procerum.

Leptographium procerum has been demonstrated to play important roles in the invasive success of red turpentine beetle (RTB), one of the most destructive invasive pests in China. Our previous studies found that bacterial volatile ammonia plays an important role in the maintenance of the RTB-L. procerum invasive complex. In this study, we found a GPCR gene Gpr-1 that was a response to ammonia but not involved in the ammonia-induced carbohydrate metabolism. Deletion of Gpr-1 significantly inhibited the growth and pathogenicity but thickened the cell wall of L. procerum, resulting in more resistance to cell wall-perturbing agents. Further analyses suggested that Gpr-1 deletion caused growth defects that might be due to the dysregulation of the amino acid and lipid metabolisms. The thicker cell wall in the ΔGpr-1 mutant was induced through the cell wall remodeling process. Our results indicated that Gpr-1 is essential for the growth of L. procerum by regulating the nutritional metabolism, which can be further explored for potential applications in the management of RTB.

Olesoxime protects against cisplatin-induced acute kidney injury by attenuating mitochondrial dysfunction.

BACKGROUND: Mitochondrial dysfunction is a critical factor in the pathogenesis of acute kidney injury (AKI). Agents that ameliorate mitochondrial dysfunction hold potential for AKI treatment. The objective of this study was to investigate the impact of olesoxime, a novel mitochondrial-targeted agent, on cisplatin-induced AKI. METHODS: In vivo, a cisplatin-induced AKI mouse model was established by administering a single intraperitoneal dose of cisplatin (25 mg/kg) to male C57BL/6 mice for 72 hours, followed by gavage of either olesoxime or a control solution. In vitro, human proximal tubular HK2 cells were cultured and subjected to treatments with cisplatin, either in the presence or absence of olesoxime. RESULTS: In vivo, our findings demonstrated that olesoxime administration significantly mitigated the nephrotoxic effects of cisplatin in mice, as evidenced by reduced blood urea nitrogen (BUN) and serum creatinine (SCr) levels, improved renal histopathology, and decreased expression of renal tubular injury markers such as kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Furthermore, olesoxime administration markedly reduced cisplatin-induced apoptosis, inflammation, and oxidative stress in the kidneys of AKI mice. Additionally, olesoxime treatment effectively restored mitochondrial function in the kidneys of AKI mice. In vitro, our results indicated that olesoxime treatment protected against cisplatin-induced apoptosis and mitochondrial dysfunction in cultured HK2 cells. Notably, cisplatin's anticancer effects were unaffected by olesoxime treatment in human cancer cells. CONCLUSION: The results of this study suggest that olesoxime is a viable and efficient therapeutic agent in the treatment of cisplatin-induced acute kidney injury presumably by alleviating mitochondrial dysfunction.

Overexpression of Phosphoserine Aminotransferase (PSAT)-Enhanced Cadmium Resistance and Accumulation in Duckweed (Lemna turionifera 5511).

Cadmium (Cd) hampers plant growth and harms photosynthesis. Glutamate (Glu) responds to Cd stress and activates the Ca2+ signaling pathway in duckweed, emphasizing Glu's significant role in Cd stress. In this study, we overexpressed phosphoserine aminotransferase (PSAT), a crucial enzyme in Glu metabolism, in duckweed. We investigated the response of PSAT-transgenic duckweed to Cd stress, including growth, Glu metabolism, photosynthesis, antioxidant enzyme activity, Cd2+ flux, and gene expression. Remarkably, under Cd stress, PSAT-transgenic duckweed prevented root abscission, upregulated the expression of photosynthesis ability, and increased Chl a, Chl b, and Chl a + b levels by 13.9%, 7%, and 12.6%, respectively. Antioxidant enzyme activity (CAT and SOD) also improved under Cd stress, reducing cell membrane damage in PSAT-transgenic duckweeds. Transcriptomic analysis revealed an upregulation of Glu metabolism-related enzymes in PSAT-transgenic duckweed under Cd stress. Moreover, metabolomic analysis showed a 68.4% increase in Glu content in PSAT duckweed exposed to Cd. This study sheds novel insights into the role of PSAT in enhancing plant resistance to Cd stress, establishing a theoretical basis for the impact of Glu metabolism on heavy metal tolerance in plants.

WWP2 deletion aggravates acute kidney injury by targeting CDC20/autophagy axis.

INTRODUCTION: Acute kidney injury (AKI) is associated with high morbidity and mortality rates. The molecular mechanisms underlying AKI are currently being extensively investigated. WWP2 is an E3 ligase that regulates cell proliferation and differentiation. Whether WWP2 plays a regulatory role in AKI remains to be elucidated. OBJECTIVES: We aimed to investigate the implication of WWP2 in AKI and its underlying mechanism in the present study. METHODS: We utilized renal tissues from patients with AKI and established AKI models in global or tubule-specific knockout (cKO) mice strains to study WWP2's implication in AKI. We also systemically analyzed ubiquitylation omics and proteomics to decipher the underlying mechanism. RESULTS: In the present study, we found that WWP2 expression significantly increased in the tubules of kidneys with AKI. Global or tubule-specific knockout of WWP2 significantly aggravated renal dysfunction and tubular injury in AKI kidneys, whereas WWP2 overexpression significantly protected tubular epithelial cells against cisplatin. WWP2 deficiency profoundly affected autophagy in AKI kidneys. Further analysis with ubiquitylation omics, quantitative proteomics and experimental validation suggested that WWP2 mediated poly-ubiquitylation of CDC20, a negative regulator of autophagy. CDC20 was significantly decreased in AKI kidneys, and selective inhibiting CDC20 with apcin profoundly alleviated renal dysfunction and tubular injury in the cisplatin model with or without WWP2 cKO, indicating that CDC20 may serve as a downstream target of WWP2 in AKI. Inhibiting autophagy with 3-methyladenine blocked apcin's protection against cisplatin-induced renal tubular cell injury. Activating autophagy by rapamycin significantly protected against cisplatin-induced AKI in WWP2 cKO mice, whereas inhibiting autophagy by 3-methyladenine further aggravated apoptosis in cisplatin-exposed WWP2 KO cells. CONCLUSION: Taken together, our data indicated that the WWP2/CDC20/autophagy may be an essential intrinsic protective mechanism against AKI. Further activating WWP2 or inhibiting CDC20 may be novel therapeutic strategies for AKI.

Roles of DNA damage in renal tubular epithelial cells injury.

The prevalence of renal diseases including acute kidney injury (AKI) and chronic kidney disease (CKD) is increasing worldwide. However, the pathogenesis of most renal diseases is still unclear and effective treatments are still lacking. DNA damage and the related DNA damage response (DDR) have been confirmed as common pathogenesis of acute kidney injury and chronic kidney disease. Reactive oxygen species (ROS) induced DNA damage is one of the most common types of DNA damage involved in the pathogenesis of acute kidney injury and chronic kidney disease. In recent years, several developments have been made in the field of DNA damage. Herein, we review the roles and developments of DNA damage and DNA damage response in renal tubular epithelial cell injury in acute kidney injury and chronic kidney disease. In this review, we conclude that focusing on DNA damage and DNA damage response may provide valuable diagnostic biomarkers and treatment strategies for renal diseases including acute kidney injury and chronic kidney disease.

Acetylcholine (ACh) enhances Cd tolerance through transporting ACh in vesicles and modifying Cd absorption in duckweed (Lemna turionifera 5511).

Acetylcholine (ACh), an important neurotransmitter, plays a role in resistance to abiotic stress. However, the role of ACh during cadmium (Cd) resistance in duckweed (Lemna turionifera 5511) remains uncharacterized. In this study, the changes of endogenous ACh in duckweed under Cd stress has been investigated. Also, how exogenous ACh affects duckweed's ability to withstand Cd stress was studied. The ACh sensor transgenic duckweed (ACh 3.0) showed the ACh signal response under Cd stress. And ACh was wrapped and released in vesicles. Cd stress promoted ACh content in duckweed. The gene expression analysis showed an improved fatty acid metabolism and choline transport. Moreover, exogenous ACh addition enhanced Cd tolerance and decreased Cd accumulation in duckweed. ACh supplement reduced the root abscission rate, alleviated leaf etiolation, and improved chlorophyll fluorescence parameters under Cd stress. A modified calcium (Ca2+) flux and improved Cd2+ absorption were present in conjunction with it. Thus, we speculate that ACh could improve Cd resistance by promoting the uptake and accumulation of Cd, as well as the response of the Ca2+ signaling pathway. Also, plant-derived extracellular vesicles (PDEVs) were extracted during Cd stress. Therefore, these results provide new insights into the response of ACh during Cd stress.

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) drives chronic kidney disease progression in male mice.

Kidney injury initiates epithelial dedifferentiation and myofibroblast activation during the progression of chronic kidney disease. Herein, we find that the expression of DNA-PKcs is significantly increased in the kidney tissues of both chronic kidney disease patients and male mice induced by unilateral ureteral obstruction and unilateral ischemia-reperfusion injury. In vivo, knockout of DNA-PKcs or treatment with its specific inhibitor NU7441 hampers the development of chronic kidney disease in male mice. In vitro, DNA-PKcs deficiency preserves epithelial cell phenotype and inhibits fibroblast activation induced by transforming growth factor-beta 1. Additionally, our results show that TAF7, as a possible substrate of DNA-PKcs, enhances mTORC1 activation by upregulating RAPTOR expression, which subsequently promotes metabolic reprogramming in injured epithelial cells and myofibroblasts. Taken together, DNA-PKcs can be inhibited to correct metabolic reprogramming via the TAF7/mTORC1 signaling in chronic kidney disease, and serve as a potential target for treating chronic kidney disease.

FADD phosphorylation contributes to development of renal fibrosis by accelerating epithelial-mesenchymal transition.

FADD, a classical apoptotic signaling adaptor, has recently been reported to exhibit a series of non-apoptotic functions. Here, we report that FADD may play a critical role in the development of renal fibrosis. Neutrophil infiltration in the renal interstitial part, glomerular mesangial cell proliferation, and base-membrane thickening were observed in FADD-D mice by H&E, PAS, and PASM staining. Immunofluorescence analysis revealed that macrophage infiltration was significantly enhanced in FADD-D mice. Renal fibrosis might be induced by IgA nephritis in FADD-D mice as evidenced by increased Ki67 and type IV collagen. Additionally, the levels of α-SMA, Fibronectin, and Vimentin were also found to be elevated. Mechanism study indicated that the TLR4/myD88/NF-κB signaling pathway was activated in FADD-D mice. Moreover, FADD phosphorylation activated the mTOR and TGF-ß/Smad pathway and accelerated the process of epithelial mesenchymal transition. Further studies indicated that the TGF-ß1 pathway was also activated and the process of EMT was accelerated in both FADD-disrupted HEK293 cells and FADD-deficient MES cells. Thus, we concluded that FADD phosphorylation could lead to IgA nephritis and eventually result in renal fibrosis. Taken together, our study provides evidence, for the first time, that FADD, especially in its phosphorylated form, has an effect on the development of renal fibrosis.Abbreviations: FADD: FAS-associated protein with death domain; DED: death effector domain; DD: death domain; CKD: chronic kidney disease; ECM: extracellular matrix; ESRD: end-stage renal disease; RRT: renal replacement therapy; H&E: hematoxylin and eosin; PASM: periodic acid silver methenamine.

New Insight into the Function of Dopamine (DA) during Cd Stress in Duckweed (Lemna turionifera 5511).

Dopamine (DA), a kind of neurotransmitter in animals, has been proven to cause a positive influence on plants during abiotic stress. In the present study, the function of DA on plants under cadmium (Cd) stress was revealed. The yellowing of duckweed leaves under Cd stress could be alleviated by an exogenous DA (10/20/50/100/200 µM) supplement, and 50 µM was the optimal concentration to resist Cd stress by reducing root breakage, restoring photosynthesis and chlorophyll content. In addition, 24 h DA treatment increased Cd content by 1.3 times in duckweed under Cd stress through promoting the influx of Cd2+. Furthermore, the gene expression changes study showed that photosynthesis-related genes were up-regulated by DA addition under Cd stress. Additionally, the mechanisms of DA-induced Cd detoxification and accumulation were also investigated; some critical genes, such as vacuolar iron transporter 1 (VIT1), multidrug resistance-associated protein (MRP) and Rubisco, were significantly up-regulated with DA addition under Cd stress. An increase in intracellular Ca2+ content and a decrease in Ca2+ efflux induced by DA under Cd stress were observed, as well as synchrony with changes in the expression of cyclic nucleotide-gated ion channel 2 (CNGC2), predicting that, in plants, CNGC2 may be an upstream target for DA action and trigger the change of intracellular Ca2+ signal. Our results demonstrate that DA supplementation can improve Cd resistance by enhancing duckweed photosynthesis, changing intracellular Ca2+ signaling, and enhancing Cd detoxification and accumulation. Interestingly, we found that exposure to Cd reduced endogenous DA content, which is the result of a blocked shikimate acid pathway and decreased expression of the tyrosine aminotransferase (TAT) gene. The function of DA in Cd stress offers a new insight into the application and study of DA to Cd phytoremediation in aquatic systems.

Mitochondrial Targeted Antioxidant SKQ1 Ameliorates Acute Kidney Injury by Inhibiting Ferroptosis.

Emerging evidence suggests that ferroptosis is highly correlated with the pathogenesis of acute kidney injury (AKI). Ferroptosis, an iron-dependent form of cell death, is manifested by a toxic accumulation of lipid peroxides and ultrastructural changes in mitochondria. We herein investigated the effect of Visomitin (SKQ1), a novel mitochondria-targeting antioxidant, on several AKI models in vivo and in vitro. Our results revealed that SKQ1 treatment greatly reversed renal outcomes in cisplatin, ischemia-reperfusion injury (IRI), or folic acid-induced AKI models. These effects were reflected in attenuated levels of renal injury biomarkers, histologic indices of tubular injury, and inflammatory infiltration in the SKQ1-treated groups. Transcriptomics analysis depicted ferroptosis signaling as the most pronounced pathway downregulated after SKQ1 treatment. Consequently, administration of SKQ1 significantly ameliorated lipid peroxide accumulation and inhibited ferroptosis in the kidneys of mice with AKI. In cultured human proximal tubule epithelial cells (HK2), SKQ1 treatment markedly mitigated cisplatin-induced mitochondrial reactive oxygen species (ROS) production, resulting in lower levels of lipid peroxidation and ferroptosis. In conclusion, SKQ1 treatment protected against ischemic- or nephrotoxic-induced AKI by inhibiting ferroptosis in vivo and in vitro. These results could facilitate a broader understanding of the interaction between mitochondrial antioxidants and ferroptotic defense mechanisms, providing a possible therapeutic strategy in AKI.

Ursodeoxycholic acid protects against cisplatin-induced acute kidney injury and mitochondrial dysfunction through acting on ALDH1L2.

Mitochondrial dysfunction plays an important role in acute kidney injury (AKI). Thus, the agents improving the mitochondrial function could be beneficial for treating AKI. Ursodeoxycholic acid (UDCA) has been demonstrated to prevent mitochondrial dysfunction under pathology, however, its role in AKI and the underlying mechanism remain unknown. This study aimed to evaluate the effect of UDCA on cisplatin-induced AKI. In vivo, C57BL/6 J mice were treated with cisplatin (25 mg/kg) for 72 h to induce AKI through a single intraperitoneal (i.p.) injection with or without UDCA (60 mg/kg/day) administration by gavage. Renal function, mitochondrial function and oxidative stress were analyzed to evaluate kidney injury. In vitro, mouse proximal tubular cells (mPTCs) and human proximal tubule epithelial cells (HK2) were treated with cisplatin with or without UDCA treatment for 24 h. Transcriptomic RNA-seq was preformed to analyze possible targets of UDCA. Our results showed that cisplatin-induced increments of serum creatinine (Scr), blood urea nitrogen (BUN), and cystatin C were significantly reduced by UDCA along with ameliorated renal tubular injury evidenced by improved renal histology and blocked upregulation of neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1). Meanwhile, the apoptosis induced by cisplatin was also markedly attenuated by UDCA administration. In vitro, UDCA treatment protected against tubular cell apoptosis possibly through antagonizing mitochondrial dysfunction and oxidative stress by targeting ALDH1L2 which was screened out by an RNA-seq analysis. Knockout of ALDH1L2 by CRISPR/Cas9 greatly blunted the protective effects of UDCA in renal tubular cells. Moreover, UDCA did not diminish cisplatin's antineoplastic effect in human cancer cells. In all, our results demonstrated that UDCA protects against cisplatin-induced AKI through improving mitochondrial function through acting on the expression of ALDH1L2, suggesting a clinical potential of UDCA for the treatment of AKI.