A novel crosstalk between Nrf2 and Smad2/3 bridged by two nuanced Keap1 isoforms with their divergent effects on these distinct family transcription factors

Engineered Extracellular Vesicle-Based Nanoformulations That Coordinate Neuroinflammation and Immune Homeostasis, Enhancing Parkinson's Disease Therapy

Although conventional intervention to microglia can mitigate neuroinflammation in the short term, immune disorders by peripheral inflammatory cells can infiltrate continuously, resulting in an overactivated immune microenvironment of Parkinson's disease (PD). Here, we design engineered extracellular vesicle-based nanoformulations (EVNs) to address multiple factors for the management of PD. Specifically, EVN is developed by coating CCR2-enriched mesenchymal stem cell-derived extracellular vesicles (MSCCCR2 EVs) onto a dihydrotanshinone I-loaded nanocarrier (MSeN-DT). The MSCCCR2 EVs (the shell of EVN) can actively show homing to specific chemokines CCL2 in the substantia nigra, which enables them to block the infiltration of peripheral inflammatory cells. Interestingly, MSeN-DT (the core of EVN) can promote the Nrf2-GPX4 pathway for the suppression of the source of inflammation by inhibiting ferroptosis in microglia. In the PD model mice, a satisfactory therapeutic effect is achieved, with inhibition of peripheral inflammatory cell infiltration, precise regulation of inflammatory microglia in the substantia nigra, as well as promotion of behavioral improvement and repairing damaged neurons. In this way, the combinatorial code of alleviation of inflammation and modulation of immune homeostasis can reshape the immune microenvironment in PD, which bridges internal anti-inflammatory and external immunity. This finding reveals a comprehensive therapeutic paradigm for PD that breaks the vicious cycle of immune overactivation.

Regulation of oxidative stress in the intestine of piglets after enterotoxigenic Escherichia coli (ETEC) infection

Enterotoxigenic Escherichia coli (ETEC) is recognized globally as a major gastrointestinal pathogen that impairs intestinal function. ETEC infection can lead to oxidative stress and disruption of intestinal integrity. The present study investigated the mechanism of increased oxidative stress and whether restoration of antioxidant defense could improve intestinal integrity in a piglet model with ETEC infection. Weaned piglets were divided into three groups: control, ETEC-infection and ETEC-infection with antibiotic supplementation. The infection caused a significant elevation of serum diamine oxidase activity and D-lactate levels coupled with a reduced intestinal (mid-jejunum) tight-junction protein expression, suggesting increased intestinal permeability and impaired gut function. The infection also inhibited nuclear factor erythroid 2-related factor 2 (Nrf2) activation, decreased the expression of glutathione synthesizing enzymes, superoxide dismutase-1 (SOD1), and heme oxygenase-1 (HO-1) in the intestine. This led to a decreased antioxidant glutathione level and an increased lipid peroxidation in the intestine and serum, indicating oxidative stress. The infection stimulated the expression of pro-inflammatory cytokines (IL-6, TNF-α). Antibiotic supplementation attenuated oxidative stress, in part, through restoration of glutathione levels and antioxidant enzyme expression in the intestine. Such a treatment enhanced tight-junction protein expression and improved intestinal function. Furthermore, induction of oxidative stress in Caco2 cells by hydrogen peroxide inhibited tight-junction protein expression and stimulated inflammatory cytokine expression. Glutathione supplementation effectively attenuated oxidative stress and restored tight-junction protein expression. These results suggest that downregulation of Nrf2 activation may weaken antioxidant defense and increase oxidative stress in the intestine. Mitigation of oxidative stress can improve intestinal function after infection.