The glycolytic enzyme PFKFB3 drives kidney fibrosis through promoting histone lactylation-mediated NF-κB family activation.

Persistently elevated glycolysis in kidney has been demonstrated to promote chronic kidney disease (CKD). However, the underlying mechanism remains largely unclear. Here, we observed that 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), a key glycolytic enzyme, was remarkably induced in kidney proximal tubular cells (PTCs) following ischemia-reperfusion injury (IRI) in mice, as well as in multiple etiologies of patients with CKD. PFKFB3 expression was positively correlated with the severity of kidney fibrosis. Moreover, patients with CKD and mice exhibited increased urinary lactate/creatine levels and kidney lactate, respectively. PTC-specific deletion of PFKFB3 significantly reduced kidney lactate levels, mitigated inflammation and fibrosis, and preserved kidney function in the IRI mouse model. Similar protective effects were observed in mice with heterozygous deficiency of PFKFB3 or those treated with a PFKFB3 inhibitor. Mechanistically, lactate derived from PFKFB3-mediated tubular glycolytic reprogramming markedly enhanced histone lactylation, particularly H4K12la, which was enriched at the promoter of NF-κB signaling genes like Ikbkb, Rela, and Relb, activating their transcription and facilitating the inflammatory response. Further, PTC-specific deletion of PFKFB3 inhibited the activation of IKKß, I κ B α, and p65 in the IRI kidneys. Moreover, increased H4K12la levels were positively correlated with kidney inflammation and fibrosis in patients with CKD. These findings suggest that tubular PFKFB3 may play a dual role in enhancing NF-κB signaling by promoting both H4K12la-mediated gene transcription and its activation. Thus, targeting the PFKFB3-mediated NF-κB signaling pathway in kidney tubular cells could be a novel strategy for CKD therapy.

Loss of BAF (mSWI/SNF) chromatin-remodeling ATPase Brg1 causes multiple malformations of cortical development in mice.

Mutations in genes encoding subunits of the BAF (BRG1/BRM-associated factor) complex cause various neurodevelopmental diseases. However, the underlying pathophysiology remains largely unknown. Here, we analyzed the function of Brahma-related gene 1 (Brg1), a core ATPase of BAF complexes, in the developing cerebral cortex. Loss of Brg1 causes several morphological defects resembling human malformations of cortical developments (MCDs), including microcephaly, cortical dysplasia, cobblestone lissencephaly and periventricular heterotopia. We demonstrated that neural progenitor cell renewal, neuronal differentiation, neuronal migration, apoptotic cell death, pial basement membrane and apical junctional complexes, which are associated with MCD formation, were impaired after Brg1 deletion. Furthermore, transcriptome profiling indicated that a large number of genes were deregulated. The deregulated genes were closely related to MCD formation, and most of these genes were bound by Brg1. Cumulatively, our study indicates an essential role of Brg1 in cortical development and provides a new possible pathogenesis underlying Brg1-based BAF complex-related neurodevelopmental disorders.

Prognostic significance of hypertension at the onset of lupus nephritis in Chinese patients: prevalence and clinical outcomes.

The demographic features, and clinical and histological characteristics of lupus nephritis (LN) patients with hypertension in the Chinese population remain unclear. Hence, the clinical characteristics of LN with and without hypertension were retrospectively analyzed. A total of 764 LN patients (53.1%) were hypertensive. These hypertensive patients had higher levels of serum creatinine and blood urea nitrogen, and lower estimated glomerular filtration rates, when compared to their normotensive counterparts (P < 0.05). Furthermore, these hypertensive patients had higher median acuity index and chronicity index scores, when compared to normotensives (P < 0.001). In terms of histology, hypertensive patients were more likely to develop glomerular sclerosis, thickened glomerular capillary loops, or crescent formations, and had more severe endothelial cell proliferation, when compared to normotensive patients (P < 0.001). Hypertensive patients also had a higher percentage for more severe tubular atrophy, interstitial inflammatory cell infiltration and interstitial fibrosis (P < 0.001). Compared with normotensive patients, hypertensive patients exhibited a significant decline in survival time and rate for all end points (P < 0.01). The presence of hypertension was an independent predictor of mortality (P = 0.009), ESRD (P = 0.026), and doubling of serum creatinine (P = 0.017). In conclusion, hypertension is associated with poor clinical and renal outcome in LN patients. The monitoring and control of hypertension should be considered an important clinical goal in the treatment of LN patients.

Risk factors and clinical outcomes of encapsulating peritoneal sclerosis: A case-control study from China.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is an uncommon, but serious complication in patients with continuous ambulatory peritoneal dialysis (PD) who have a considerable mortality rate. This study aimed to identify risk factors and outcomes of EPS in Chinese patients on PD. METHODS: Sixteen patients on PD who met the International Society for Peritoneal Dialysis criteria for diagnosis of EPS in the First Affiliated Hospital of Sun Yat-Sen University from 1997 to 2018 were included. Patients without EPS were matched for age, sex and the duration of PD and selected at a 1:3 ratio for the controls. A case-control study was conducted to analyse the clinical profile and risk factors associated with EPS in patients. RESULTS: The prevalence of EPS in patients on PD in our centre was 0.55%. The percentage of EPS significantly increased with the duration of PD. In univariate regression analysis, a history of peritonitis (odds ratios (OR): 2.83; 95% confidence interval (CI): 0.82-9.68; p = 0.08), peritoneal glucose exposure (OR: 1.12; 95% CI: 1.03-1.22; p < 0.01) and a high peritoneal transport status (OR: 14.70; 95% CI: 1.85-117.02; p < 0.01) were associated with EPS in patients on PD. However in the multivariate model, only a high peritoneal transport status (adjusted odds ratios (aOR): 13.65; 95% CI: 1.69-109.96; p = 0.01) was independently associated with EPS. CONCLUSION: The rate of EPS significantly increases with the duration of PD. Progressive peritoneal dysfunction, especially a high peritoneal transport status, is associated with a higher risk of EPS in this population.

Bifenthrin induces DNA damage and autophagy in Spodoptera frugiperda (Sf9) insect cells.

Bifenthrin is one of the most commonly used synthetic pyrethroid insecticides. It targets the nervous system of insects, mainly acting on sodium channels in nerve cell membranes. The high use of bifrenthrin may lead to an increase in pest insect resistance. Additionally, there are only a few studies describing its cytotoxic action. A series of bioassays were carried out, and the results showed that bifenthrin has a significant ability to induce DNA damage and the inhibition of viability in Spodoptera frugiperda (Sf9) cells. Monodansylcadaverine staining and transmission electron microscope assays were used to observe significant levels of autophagosomes and mitochondrial dysfunction in the cytoplasm. Additionally, western blot analysis showed an upregulation in LC3-II and beclin-1 protein expression and a downregulation in p62 expression, which contributed to the cytotoxic effect of bifenthrin on Sf9 cells. Overall, bifenthrin significantly impacts the viability of Sf9 cells by inducing DNA damage and autophagy. These results provide a theoretical basis for understanding bifrenthin's mechanism of cytotoxicity.

Ten-year survival of patients treated with peritoneal dialysis: A prospective observational cohort study.

BACKGROUND: Few studies evaluated over 5-year outcomes of dialysis patients. This study examined 10-year all-cause mortality and death-censored technique failure in a cohort of incident peritoneal dialysis (PD) individuals. METHODS: Five hundred and thirty-three incident PD individuals from 2006 to 2008 were prospectively followed up for more than 10 years until 2018. Clinical characteristics at PD initiation were collected. The primary outcome was all-cause mortality, and the secondary outcome was death-censored technique failure. Cox hazards models were fit using clinical characteristics at PD initiation. RESULTS: The mean age starting PD for these participants was 48 ± 16 years; 130 (24%) patients had diabetic nephropathy. During follow-up, 208 patients died, and 84 patients experienced technique failures. The 1, 3, 5, and 10 years' survival rates for incident PD patients were 93%, 81%, 64%, and 36%, respectively, and the technical survival rates were 98%, 93%, 85%, and 62%, respectively. Mortality risk was much higher after 3 years on PD. The peritonitis rate was 0.19 episodes per patient-year, and 7 (1.3%) patients had encapsulating peritoneal sclerosis (EPS) giving an incidence rate of 3.1 of 1000 patient-years. The main causes of death were cardiovascular events (97 of 208, 47%), and technique failure was mainly due to peritonitis (41 of 84, 49%). Older age, higher Charlson comorbidity index, and lower level of education were strongly associated with mortality, and diabetic nephropathy was an independent risk factor for technique failure. CONCLUSIONS: The 10-year's survival and technique survival rates of incident PD patients were 36% and 62%. Long-term PD can be continued successfully with improved outcomes and low risk for EPS.

Drp1-mediated mitochondrial fission promotes renal fibroblast activation and fibrogenesis.

Excessive mitochondrial fission acts as a pro-proliferative marker in some cancers and organ fibrosis; its potential role in renal fibroblast activation and fibrogenesis has never been investigated. Here, we showed more pronounced fragmented mitochondria in fibrotic than in non-fibrotic renal fibroblast in humans and mice. In a mouse model of obstructive nephropathy, phosphorylation of Drp1 at serine 616 (p-Drp1S616) and acetylation of H3K27(H3K27ac) was increased in fibrotic kidneys; pharmacological inhibition of mitochondrial fission by mdivi-1 substantially reduced H3K27ac levels, fibroblasts accumulation, and interstitial fibrosis. Moreover, mdivi-1 treatment was able to attenuate the established renal fibrosis. In cultured renal interstitial fibroblasts, targeting Drp1 using pharmacological inhibitor or siRNA suppressed TGF-ß1-elicited cell activation and proliferation, as evidenced by inhibiting expression of α-smooth muscle actin (α-SMA) and collagen I, as well as by reducing DNA synthesis. In contrast, Drp1 deletion enhanced cell apoptosis, along with decreased mitochondrial fragmentation, mtROS elevation, and glycolytic shift upon TGF-ß1 stimulation. In Drp1 deletion fibroblasts, re-expression of wild-type Drp1 rather than Drp1S616A mutant restores the reduction of TGF-ß-induced-Drp1 phosphorylation, H3K27ac, and cell activation. Moreover, TGF-ß1 treatment increased the enrichment of H3K27ac at the promoters of α-SMA and PCNA, which was reversed in Drp1-knockdown fibroblasts co-transfected with empty vector or Drp1S616A, but not wild-type Drp1. Collectively, our results imply that inhibiting p-Drp1S616-mediated mitochondrial fission attenuates fibroblast activation and proliferation in renal fibrosis through epigenetic regulation of fibrosis-related genes transcription and may serve as a therapeutic target for retarding progression of chronic kidney disease.

Pyrethrum-extract induced autophagy in insect cells: A new target?

Pyrethrum extract (PY) is a natural insecticide that is extensively used across the world, and its insecticidal activity is attributed to the presence of six active esters known as pyrethrins. PY targets the nervous systems of insects by delaying the closure of voltage-gated sodium ion channels in the nerve cells. However, limited information is available regarding the toxicity and detailed mechanisms of PY activity. This study is aimed at understanding the toxicity effect and the underlying mechanisms of PY in cellular level, which have not yet been investigated on the non-nervous system of insects. Results of the MTT assay showed that the viability of Sf9 cells was inhibited by PY in a time- and concentration-dependent manner, and observation under a microscope revealed accumulation of intracellular vacuoles. Monodansylcadaverine staining analysis and transmission electron microscope images revealed typical autophagic morphological changes in PY-treated Sf9 cells. Autophagy-related proteins such as LC3, p62, and beclin-1 were detected using by Western blotting. Protein expression levels of LC3-II and beclin-1 were upregulated while that of p62 was markedly downregulated in a dose-dependent manner upon the PY treatment in Sf9 cells. In conclusion, these results indicate that PY could induce autophagy in the non-nervous system of insects which may contribute to its insecticidal mechanism.

The organophosphate insecticide chlorpyrifos confers its genotoxic effects by inducing DNA damage and cell apoptosis.

The organophosphate insecticide chlorpyrifos (CPF) is known to induce neurological effects, malformation and micronucleus formation, persistent developmental disorders, and maternal toxicity in rats and mice. The binding of chlorpyrifos with DNA to produce DNA adducts leads to an increasing social concern about the genotoxic risk of CPF in human, but CPF-induced cytotoxicity through DNA damage and cell apoptosis is not well understood. Here, we quantified the cytotoxicity and potential genotoxicity of CPF using the alkaline comet assay, γH2AX foci formation, and the DNA laddering assay in order to detect DNA damage and apoptosis in human HeLa and HEK293 cells in vitro. Drosophila S2 cells were used as a positive control. The alkaline comet assay showed that sublethal concentrations of CPF induced significant concentration-dependent increases in single-strand DNA breaks in the treated cells compared with the control. The percentage of γH2AX-positive HeLa cells revealed that CPF also causes DNA double-strand breaks in a time-dependent manner. Moreover, DNA fragmentation analysis demonstrated that exposure to CPF induced a significant concentration- and time-dependent increase in cell apoptosis. We conclude that CPF is a strongly genotoxic agent that induces DNA damage and cell apoptosis.

Comparison of the cytotoxic impact of chlorfluazuron on selected insect and human cell lines.

To gain new insight into the mechanism of selective cytotoxicity of benzoylureas as insecticides, the in vitro mode of action of chlorfluazuron was investigated on lepidopteran Tn5B1-4 and Sf-21 cells and human Hek293 and HepG2 cells. Chlorfluazuron inhibited the proliferation of Tn5B1-4 and Sf-21 cells with 50% inhibitory concentration values (IC50) of 4.96 µM and 1.12 µM at 48 h and 2.37 µM and 1.76 µM at 96 h, respectively, versus that of Hek293 and HepG2 cells with IC50 values >20 µM. When transferred to chlorfluazuron-free medium, lepidopteran Tn5B1-4 and Sf-21 cells had a postinhibitory recovery development period within 24 h followed by a suppressed increase in cell viability, but human Hek293 and HepG2 cells showed an accelerated increase over their control level. Chlorfluazuron affected Tn5B1-4 and Sf-21 cells, with ≥1.8-fold decreases in the ratio of cellular N-acetylglucosamine (GlcNAc) level and protein content and ≥1.5-fold increases in the mitotic index and G2 /M-phase arrest. Neither Hek293 nor HepG2 cells contained GlcNAc, and chlorfluazuron had no significant effects on the cell cycle and mitotic index of Hek293 and HepG2 cells. In conclusion, the differences between human and lepidopteran cell lines in the characteristic GlcNAc content, G2 /M arrest in the cycle progress, and mitotic index of cells in response to chlorfluazuron may contribute to the selective toxicity of chlorfluazuron to lepidopteran cells.