Modifiable Lifestyle, Sedentary Behaviors and the Risk of Frailty: A Univariate and Multivariate Mendelian Randomization Study.

This research conducted a two-sample univariate and multivariate Mendelian Randomization (MR) analysis to explore the causal link between different types of leisure sedentary behavior (LSB) and frailty. Independent instrumental variables significantly associated with sedentary behaviors (p < 5 × 10-8) are obtained from a genome-wide association study (GWAS) of 422,218 individuals, and Frailty Index (FI) are derived from the latest GWAS dataset of 175,226 individuals. MR analysis is conducted using inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode, supplemented by MRAPSS. Univariate MR revealed that sedentary behaviors such as watching television increased the risk of frailty (OR, 1.271; 95% CI: 1.202-1.345; p = 6.952 × 10-17), as sedentary driving behaviors are done (OR, 1.436; 95% CI: 1.026-2.011; p = 0.035). Further validation through APSS, taking into account cryptic relatedness, stratification, and sample overlap, maintained the association between television viewing and increased frailty risk (OR, 1.394; 95% CI: 1.266-1.534; p = 1.143 × 10-11), while the association with driving dissipated. In multivariate inverse variance weighted (IVW) analysis, after adjusting for C-reactive protein (CRP) levels, television Sedentary behavior (SB) inversely affected frailty (OR, 0.782; 95% CI: 0.724-0.845; p = 4.820 × 10-10). This study indicates that televisio SB significantly increases the risk of frailty, suggesting potential biological heterogeneity behind specific sedentary activities. This process may interact with inflammation, influencing the development of frailty.

Correction to: Mild endoplasmic reticulum stress ameliorates lipopolysaccharide-induced neuroinflammation and cognitive impairment via regulation of microglial polarization.

An amendment to this paper has been published and can be accessed via the original article.

Pro-inflammatory role of high-mobility group box-1 on brain mast cells via the RAGE/NF-κB pathway.

High-mobility group box-1 (HMGB-1) acts as a pro-inflammatory cytokine contributing to the occurrence of many central inflammatory and infectious disorders. Brain mast cells (MCs) are the first responders to peripheral inflammatory stimulation because of their rapid response to external stimuli coupled with their release of preformed and newly synthesized reactive chemicals. Little is known about the involvement of brain MCs in the pro-inflammatory effects of HMGB-1 on the central nervous system (CNS). Thus, we investigated the activation process of MCs by HMGB-1 and explored whether this process is involved in the pro-inflammatory effects of HMGB-1 on the CNS. In this study, we used P815 cells to study the activating role of HMGB-1 on MCs and to explore its potential mechanism in vitro. In an in vivo study, adult male Sprague-Dawley rats received i.c.v. injection of sterile saline or cromoglycate (stabilizer of MCs) 30 min prior to i.p. injection of HMGB-1. Increased levels of tumor necrosis factor and IL-1ß were observed in the P815 cells, as well as in the rats' brains, after HMGB-1 treatment. Pretreatment with the receptor of advanced glycation endproducts (RAGE)-siRNA inhibited the HMGB-1-induced inflammatory process in the P815 cells. Activation of the RAGE/nuclear factor-κB (NF-κB) pathway was observed in both the P815 cells and rats' brains. In addition, HMGB-1 induced the accumulation of brain MCs in the hippocampal CA1 region, and the blood-brain barrier was disrupted. Pretreatment with cromoglycate, a stabilizer of MCs, mitigated these HMGB-1-induced pro-inflammatory processes in rats. These findings indicate that brain MCs are involved in the pro-inflammatory effect of HMGB-1 on the CNS, probably via activating the RAGE/NF-κB pathway.

Mild endoplasmic reticulum stress ameliorates lipopolysaccharide-induced neuroinflammation and cognitive impairment via regulation of microglial polarization.

BACKGROUND: Neuroinflammation, which ultimately leads to neuronal loss, is considered to play a crucial role in numerous neurodegenerative diseases. The neuroinflammatory process is characterized by the activation of glial cells such as microglia. Endoplasmic reticulum (ER) stress is commonly associated with impairments in neuronal function and cognition, but its relationship and role in neurodegeneration is still controversial. Recently, it was confirmed that nonharmful levels of ER stress protected against experimental Parkinson's disease. Here, we investigated mild ER stress-based regulation of lipopolysaccharide (LPS)-driven neuroinflammation in rats and in primary microglia. METHODS: Male Sprague-Dawley (SD) rats received the intracerebroventricular injection of the ER stress activator tunicamycin (TM) with or without intraperitoneal injection of the ER stress stabilizer sodium 4-phenylbutyrate (4-PBA) 1 h before LPS administration. The levels of neuroinflammation and memory dysfunction were assessed 24 h after treatment. In addition, the effect of mild ER stress on microglia was determined in vitro. RESULTS: Here, we found that low doses of TM led to mild ER stress without cell or organism lethality. We showed that mild ER stress preconditioning reduced microglia activation and neuronal death as well as improved LPS-induced memory impairment in rats. In addition, pre-exposure to nonlethal doses of TM in microglia showed significant protection against LPS-induced proinflammatory cytokine production and M1/2b polarization. However, sodium 4-PBA, a compound that ameliorates ER stress, ablated this protective effect in vivo and in vitro. CONCLUSIONS: Based on our findings, we conclude that the mild ER stress not only limits the accumulation of misfolded proteins but also protects tissues from harmful endotoxemia insults. Therefore, ER stress preconditioning has potential therapeutic value for the treatment of neurodegenerative diseases.

Protective effects of Garcinol against neuropathic pain - Evidence from in vivo and in vitro studies.

Neuroinflammatory processes have a vital role in the pathogenesis of neuropathic pain. Garcinol, harvested from Garcinia indica, is known to exert potent anti-inflammatory properties. Recent studies have indicated that Garcinol may inhibit activation of nuclear factor-κB (NF-κB) by inhibiting NF-κB/p65 acetylation. These findings prompted us to evaluate the protective effects of Garcinol in the lumbar fifth spinal nerve ligation (SNL)-induced rat model of neuropathic pain and Lipopolysaccharide(LPS)-stimulated primary cultured microglia. In the present study, we found that intrathecal administration of Garcinol significantly attenuated SNL-induced nociceptive behaviors. Garcinol suppressed microglial activation as well as the expression of interleukin (IL)-1ß, IL-6, inducible nitric oxide synthase (iNOS)/nitric oxide (NO), and cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) in the spinal cord of SNL rats. It also reduced the nuclear translocation of NF-κB by decreasing acetyl-p65 protein expression. Similarly, in the in vitro study, Garcinol decreased the production of NO/iNOS, PGE2/COX-2, and proinflammatory cytokines in LPS-exposed microglia. Likewise, Garcinol inhibited the NF-κB signaling pathway by downregulating acetyl-p65 levels in LPS-challenged microglia. Our findings suggest that Garcinol may have protective effects against neuropathic pain that are associated with the inhibition of neuroinflammation in microglia. Therefore, Garcinol could be a promising agent in the treatment of neuropathic pain.