Laquinimod inhibits MMP+ induced NLRP3 inflammasome activation in human neuronal cells

Gut-brain axis: Mechanisms and potential therapeutic strategies for ischemic stroke through immune functions

After an ischemic stroke (IS) occurs, immune cells begin traveling to the brain and immune system from the gut and gastrointestinal tract, where most of them typically reside. Because the majority of the body's macrophages and more than 70% of the total immune cell pool are typically found within the gut and gastrointestinal tract, inflammation and immune responses in the brain and immune organs require the mobilization of a large number of immune cells. The bidirectional communication pathway between the brain and gut is often referred to as the gut-brain axis. IS usually leads to intestinal motility disorders, dysbiosis of intestinal microbiota, and a leaky gut, which are often associated with poor prognosis in patients with IS. In recent years, several studies have suggested that intestinal inflammation and immune responses play key roles in the development of IS, and thus may become potential therapeutic targets that can drive new therapeutic strategies. However, research on gut inflammation and immune responses after stroke remains in its infancy. A better understanding of gut inflammation and immune responses after stroke may be important for developing effective therapies. This review discusses the immune-related mechanisms of the gut-brain axis after IS and compiles potential therapeutic targets to provide new ideas and strategies for the future effective treatment of IS.

Hydrogen sulfide antagonizes sleep deprivation-induced depression- and anxiety-like behaviors by inhibiting neuroinflammation in a hippocampal Sirt1-dependent manner

Increasing evidence confirms that sleep deprivation (SD), which induces hippocampal neuroinflammation, is a risk factor for depression. Hydrogen sulfide (H₂S) is a novel neuromodulator that plays antidepressant-like role. Silent mating type information regulation 2 homolog 1 (Sirt1) is well-characterized as a regulator of mood disorder. Furthermore, we have previously reported that H₂S upregulates Sirt1 expression in the hippocampus of SD-exposed rats. Here, we explored whether H₂S ameliorates depression- and anxiety-like behaviors as well as hippocampal neuroinflammatory in SD-exposed rats and whether Sirt1 mediates these protective roles of H₂S. In the present work, we showed that NaHS (a donor of H₂S) significantly alleviated depression- and anxiety-like behaviors in the SD-exposed rats tested by novelty-suppressed feeding test (NST), forced swim test (FST), tail suspension test (TST), and elevated plus maze test (EPMT) and that NaHS attenuates neuroinflammatory in the hippocampus of SD-exposed rats, as evidenced by reducing the levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and chemokine CCL2, as well as increasing the levels of anti-inflammatory cytokines (IL-4 and IL-10) in the hippocampus. However, Sirt1 inhibitor reversed the protective effects of H₂S against SD-induced depression- and anxiety-like behaviors as well as hippocampal neuroinflammatory. In conclusion, H₂S antagonizes SD-induced depression- and anxiety-like behaviors and neuroinflammation, which is required hippocampal Sirt1. These findings suggested that H₂S is a novel approach to prevent SD-induced depression and anxiety.

Berberine Protects Against NLRP3 Inflammasome via Ameliorating Autophagic Impairment in MPTP-Induced Parkinson's Disease Model

The NLR family pyrin domain containing 3 (NLRP3) inflammasome was reported to be regulated by autophagy and activated during inflammatory procession of Parkinson’s disease (PD). Berberine (BBR) is well-studied to play an important role in promoting anti-inflammatory response to mediate the autophagy activity. However, the effect of Berberine on NLRP3 inflammasome in PD and its potential mechanisms remain unclear. Hence, in this study, we investigated the effects of BBR on 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, by evaluating their behavioral changes, dopaminergic (DA) neurons loss, neuroinflammation, NLRP3 inflammasome and autophagic activity. BBR was also applied in BV2 cells treated with 1-methyl-4-pehnyl-pyridine (MPP+). The autophagy inhibitor 3-Methyladenine (3-MA) was administrated to block autophagy activity both in vivo and in vitro. In our in vivo studies, compared to MPTP group, mice in MPTP + BBR group showed significant amelioration of behavioral disorders, mitigation of neurotoxicity and NLRP3-associated neuroinflammation, enhancement of the autophagic process in substantia nigra (SN). In vitro, compared to MPP+ group, BBR significantly decreased the level of NLRP3 inflammasome including the expressions of NLRP3, PYD and CARD domain containing (PYCARD), cleaved caspase 1 (CASP1), and mature interleukin 1 beta (IL1B), via enhancing autophagic activity. Furthermore, BBR treatment increased the formation of autophagosomes in MPP+-treated BV2 cells. Taken together, our data indicated that BBR prevents NLRP3 inflammasome activation and restores autophagic activity to protect DA neurons against degeneration in vivo and in vitro, suggesting that BBR may be a potential therapeutic to treat PD.

NaSH increases SIRT1 activity and autophagy flux through sulfhydration to protect SH-SY5Y cells induced by MPP~

Parkinson's disease (PD) is one of the most prevailing aging diseases around the world. The present study was to investigate the potential effect of hydrogen sulfide (H2S) and silent mating type information regulation 2 homolog 1 (SIRT1) in MPP~+ induced SH-SY5Y cells and its underlying mechanisms in PD. SH-SY5Y cells were induced by MPP~+ and treated with the H2S donor NaHS to detect the effect of H2S on the molecular behaviors of MPP~+ induced SH-SY5Y cells. NaHS reduced the apoptosis rate and expressions of MDA, 4-HNE and p62, while increased cell viability, autophagy flux and expressions of LC3 II/I and Beclin1 in MPP~+ induced SH-SY5Y cells. Then, levels of autophagy-related proteins and inflammation-related proteins (TNF-α, IL-Iβ) were detected, indicating that Chloroquine and Sirtinol reversed the protective effect of H2S on SH-SY5Y cells induced by MPP~+. We further explored the particular function of H2S, SH-SY5Y cells treated with MPP~+, NaHS chloroquine, and SIRT1 inhibitor (Sirtinol). The results showed that H2S increased SIRT1 expression and sulfhydration. Finally, a PD mouse model verified the above results. In a word, H2S ameliorated SIRT1 activity through acceleration of SIRT1 sulfhydration to increase the autophagy flux and attenuate damage of SH-SY5Y cells induced by MPP~+. H2S and SIRT1 activator might be a target in the treatment of PD patients.