Micro-Infusion of 5-HT1a Receptor Antagonists into the Ventral Subiculum Ameliorate MK-801 Induced Schizophrenia-Like Behavior in Rats.

Recent studies have shown that the 5-HT1a receptor (5-HT1aR) in the central 5-HT (Serotonergic) system is involved in the pathophysiology of schizophrenia through its various receptors, and the dysfunction of the ventral hippocampus may be a key causative factor in schizophrenia. To date, whether the 5-HT1a receptor is involved in ventral hippocampal dysfunction and its internal mechanism remain unclear. In this study, schizophrenia-like animal model was induced by intraperitoneal injection of aspartate receptor antagonist MK-801 in male Sprague Dawley rats, and the role of 5-HT1aR in this animal model was investigated by bilaterally micro-infusing the 5-HT1aR antagonist WAY100635 into the ventral subiculum (vSub) of the hippocampus of rats. Behavioral experiments such as open field test (OFT) and prepulse inhibition (PPI) were performed. The results showed that MK-801 induced hyperactivity and impaired prepulse inhibition in rats, whereas, micro-infusion of 5-HT1aR antagonist WAY100635 into the vSub ameliorated these phenomena. Immunofluorescence analysis revealed that WAY100635 significantly increased the c-Fos expression in vSub. Western blot and immunohistochemical analysis showed that MK-801 induced up-regulation of 5-HT1aR and phospho-extracellular regulated protein kinase (p-ERK) pathway, while micro-infusion of the WAY100635 down-regulated 5-HT1aR and p-ERK in the vSub. Therefore, the results of the present study suggested that in vSub, the 5-HT1aR antagonist WAY100635 may attenuate MK-801-induced schizophrenia-like activity by modulating excitatory neurons and downregulating p-ERK.

Mutation of the attractin gene impairs working memory in rats.

OBJECTIVE: Attractin (ATRN) is a widely expressed member of the cell adhesion and guidance protein family in humans that is closely related to cellular immunity and neurodevelopment. However, while previous studies in our laboratory have confirmed the effect of ATRN mutations on long-term memory, its specific role and the molecular mechanism by which it influences spatial cognition are poorly understood. METHODS: This study aimed to examine the effect of ATRN mutations on working memory in water maze with a novel ATRN-mutant rat generated by the CRISPR/Cas9 system; the mutation involved the substitution of the 505th amino acid, glycine (G), with cysteine (C), namely, a mutation from GGC to TGC. The changes in myelin basic protein (MBP) expression in rats were also analyzed with the western blot. RESULTS: The ATRN-G505C(KI/KI) rats exhibited significant increases in the required latency and distance traveled to locate the escape platform in a Morris water maze test of working memory. In addition, the expression of MBP was reduced in ATRN-mutant rats, as shown in the western blot analysis. CONCLUSION: Our results indicate that ATRN gene mutations may directly lead to the impairment of working memory in the water maze; this impairment may be due to the inhibition of MBP expression, which in turn affects the spatial cognition.

Cyclophilin D-mediated angiotensin II-induced NADPH oxidase 4 activation in endothelial mitochondrial dysfunction that can be rescued by gallic acid.

Vascular endothelial dysfunction plays a central role in the most dreadful human diseases, including stroke, tumor metastasis, and the coronavirus disease 2019 (COVID-19). Strong evidence suggests that angiotensin II (Ang II)-induced mitochondrial dysfunction is essential for endothelial dysfunction pathogenesis. However, the precise molecular mechanisms remain obscure. Here, polymerase-interacting protein 2 (Poldip 2) was found in the endothelial mitochondrial matrix and no effects on Poldip 2 and NADPH oxidase 4 (NOX 4) expression treated by Ang II. Interestingly, we first found that Ang II-induced NOX 4 binds with Poldip 2 was dependent on cyclophilin D (CypD). CypD knockdown (KD) significantly inhibited the binding of NOX 4 to Poldip 2, and mitochondrial ROS generation in human umbilical vein endothelial cells (HUVECs). Similar results were also found in cyclosporin A (CsA) treated HUVECs. Our previous study suggested a crosstalk between extracellular regulated protein kinase (ERK) phosphorylation and CypD expression, and gallic acid (GA) inhibited mitochondrial dysfunction in neurons depending on regulating the ERK-CypD axis. Here, we confirmed that GA inhibited Ang II-induced NOX 4 activation and mitochondrial dysfunction via ERK/CypD/NOX 4/Poldip 2 pathway, which provide novel mechanistic insight into CypD act as a key regulator of the NOX 4/Poldip 2 axis in Ang II-induced endothelial mitochondrial dysfunction and GA might be beneficial in the treatment of wide variety of diseases, such as COVID-19, which is worthy further research.

Asiatic Acid Prevents Oxidative Stress and Apoptosis by Inhibiting the Translocation of α-Synuclein Into Mitochondria.

The association of α-synuclein (α-syn) with mitochondria occurs through interaction with mitochondrial complex I. Defects in this protein have been linked to the pathogenesis of Parkinson disease (PD). Overexpression of α-synuclein in cells has been suggested to cause elevations in mitochondrial oxidant radicals and structural and functional abnormalities in mitochondria. Asiatic acid (AA), a triterpenoid, is an antioxidant that is used for depression, and we have shown that pretreatment with AA can prevent PD-like damage, but its therapeutic effects in PD and mechanism remain unknown. In this study, we found that 0.5-2 mg AA/100 g diet significantly improves climbing ability in drosophila and extends their life-span-effects that we attributed to its antioxidant properties. AA also protected mitochondria against oxidative stress and apoptosis in a rotenone-induced cellular model. In an isolated mitochondria model, AA attenuated the decline in mitochondrial membrane potential that was induced by α-syn. Consequently, AA maintained membrane integrity and ATP production. Finally, we demonstrated that AA protects by blocking the translocation of α-syn into mitochondria. Our results suggest that mitochondria are crucial in PD and that AA is an excellent candidate for the prevention and therapy of this disease.

Andrographolide sulfonate improves Alzheimer-associated phenotypes and mitochondrial dysfunction in APP/PS1 transgenic mice.

Alzheimer's disease is a neurodegenerative disorder with Amyloid-ß plaques onset, synaptic damage, and cognitive decline. Aß deposits cause pathological events including oxidative stress, mitochondrial dysfunction, and neuron death. In this study, APPswe/PSENΔ9 double transgenic mice model was used to imitate Alzheimer's disease and the effect and possible mechanism of Andrographolide sulfonate were examined. Andrographolide sulfonate was given to the mice for 7 months before the onset of Aß plaque. Spatial memory test showed that Andrographolide sulfonate treatment prevented cognitive decline. Aß deposits were not affected while hippocampus and synapse damage was significantly alleviated. Mechanism studies showed that oxidative stress and mitochondrial swelling was reduced after Andrographolide sulfonate administration. These findings suggest that Andrographolide sulfonate, which has been applied in clinical medicine, might be a promising therapeutic agent for AD therapy via mitochondria protection.

Enhanced circulating ILC2s accompany by upregulated MDSCs in patients with asthma.

Group 2 innate lymphoid cells (ILC2s) are considered to be the most significant mediators during the orchestration of immune responses in asthma. Myeloid-derived suppressor cells (MDSCs) has received a great deal of attention for their immunosuppressive activity, and our early studies indicate that the increased Th2 cytokines are associated with MDSCs. In this study, we sought to determine whether MDSCs are also participation in immune imbalance and its relationship with ILC2s in asthma. The data showed that the circulatory ILC2s or MDSCs and their characteristic cytokines or transcription factors were significantly enhanced in asthmatic patients, as well as in chronic obstructive pulmonary disease (COPD) or respiratory viral infections (RVI). Meanwhile, a Th2-dominated phenotype was found in patients with asthma which closely related to the expression levels of ILC2s and MDSCs associated moleculars. These findings indicated that Th2 polarization was close related to synergistically increased ILC2s and MDSCs, it may allow to further the comprehension of the contribution of these cells to the inflammatory response involved in asthma or other respiratory tract inflammatory diseases, such as COPD and RVI, as well as to develop novel therapeutic strategies.

Asiatic acid ameliorates dextran sulfate sodium-induced murine experimental colitis via suppressing mitochondria-mediated NLRP3 inflammasome activation.

In the present study, the effect of asiatic acid, a natural triterpenoid compound, on murine experimental colitis induced by dextran sulfate sodium (DSS) and its possible mechanism were examined in vivo and vitro. Oral administration of asiatic acid dose-dependently attenuated the loss of body weight and shortening of colon length induced by DSS. The disease activity index, histopathologic scores of musco and myeloperoxidase activity were also significantly reduced by asiatic acid treatment. Protein and mRNA levels of DSS-induced pro-inflammatory cytokines in colon, including TNF-α, IL-1ß, IL-6 and IFN-γ, were markedly suppressed by asiatic acid. At the same time, decreased activation of caspase-1 in peritoneal macrophages was detected in asiatic acid-treated mice, which suggested that the NLRP3 inflammasome activation was suppressed. In addition, we also found that asiatic acid dose-dependently inhibited IL-1ß secretion, caspase-1 activation as well as inflammasome assembling in vitro. Furthermore, the mechanism of asiatic acid was related to the inhibition of mitochondrial reactive oxygen species generation and prevention of mitochondrial membrane potential collapse. Taken together, our results demonstrate the ability of asiatic acid to inhibit NLRP3 inflammasome activation and its potential usage in the treatment of inflammatory bowel diseases.

[Expressions and implications of Th1/Th2 cytokines in injured rat brain and spinal cord].

OBJECTIVE: To detect the expression levels of Th1/Th2 cytokines in the acute injury of brain and spinal cord in rats, and explore their possible roles in sustained secondary injury. METHODS: The acute brain and spinal cord injury models in SD rats were established and randomly divided into injury group and lipopolysaccharide (LPS) treatment group, and each group was experimentally intervened in the brain and spinal cord, respectively. The mRNA of Th1/Th2 cytokines were determined by quantitative real-time PCR (qRT-PCR) and analyzed in correlation. RESULTS: Compared with the control group, in injury and LPS treatment groups, the level of IFN-γ (as a Th1 associated cytokine) in brain tissue significantly increased (P<0.05), while the expression of T-bet did not significantly change; in spinal cord, the levels of IFN-γ and transcription factors T-bet, HLX rose significantly (P<0.05). The cytokine IL-4 and transcription factor GATA3 in both injury and LPS treatment groups were as low as those in the control group. CONCLUSION: The expressions of Th1 associated cytokines, especially soluble cytokine IFN-γ, increased in brain and spinal cord injury. The up-regulated T-bet and HLX expressions were only observed in spinal injury.

Protective effects of asiatic acid on rotenone- or H2O2-induced injury in SH-SY5Y cells.

Parkinson's disease (PD) is a progressive neurodegenerative disorder with a prevalence of 1-2% in people over the age of 50. Mitochondrial dysfunction occurred in PD patients showing a 15-30% loss of activity in complex I. Asiatic acid (AA), a triterpenoid, is an antioxidant and used for depression treatment, but the effect of AA against PD-like damage has never been reported. In the present study, we investigated the protective effects of AA against H(2)O(2) or rotenone-induced cellular injury and mitochondrial dysfunction in SH-SY5Y cells. Mitochondrial membrane potential (MMP) and the expression of voltage-dependent anion channel (VDAC) were detected with or without AA pretreatment following cellular injury to address the possible mechanisms of AA neuroprotection. The results showed that pre-treatment of AA (0.01-100 nM) protected cells against the toxicity induced by rotenone or H(2)O(2). In addition, MMP dissipation occurred following the exposure of rotenone, which could be prevented by AA treatment. More interestingly, pre-administration of AA inhibited the elevation of VDAC mRNA and protein levels induced by rotenone(100 nM) or H(2)O(2) (300 microM).These data indicate that AA could protect neuronal cells against mitochondrial dysfunctional injury and suggest that AA might be developed as an agent for PD prevention or therapy.

Mitochondrial dysfunction enhances susceptibility to oxidative stress by down-regulation of thioredoxin in human neuroblastoma cells.

Increasing evidence suggests that Alzheimer's disease is associated with mitochondrial dysfunction and oxidative damage. To develop a cellular model of Alzheimer's disease, we investigated the effects of thioredoxin (Trx) expression in the response to mitochondrial dysfunction-enhanced oxidative stress in the SH-SY5Y human neuroblastoma cells. Treatment of SH-SY5Y cells with 15 mM of NaN3, an inhibitor of cytochrome c oxidase (complex IV), led to alteration of mitochondrial membrane potential but no significant changes in cell viability. Therefore, cells were first treated with 15 mM NaN3 to induce mitochondrial dysfunction, then, exposed to different concentrations of H2O2. Cell susceptibility was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay and morphological observation. Expressions of Trx mRNA and protein were determined by RT-PCR; and Western-blot analysis, respectively. It was found that the SH-SY5Y cells with mitochondrial impairment had lower levels of Trx mRNA and protein, and were significantly more vulnerable than the normal cells after exposure to H2O2 while no significant changes of Trx mRNA and protein in SH-SY5Y cells exposed to H2O2 but without mitochondrial complex IV inhibition. These results, together with our previous study in primary cultured neurons, demonstrated that the increased susceptibility to oxidative stress is induced at least in part by the down-regulation of Trx in SH-SY5Y human neuroblastoma cells with mitochondrial impairment and also suggest the mitochondrial dysfunction-enhanced oxidative stress could be used as a cellular model to study the mechanisms of Alzheimer's disease and agents for prevention and treatment.

Vulnerability of neurons with mitochondrial dysfunction to oxidative stress is associated with down-regulation of thioredoxin.

In this study, we first developed an in vitro model of neuron with mitochondrial dysfunction, based on sodium azide (NaN(3))-induced inhibition of cytochrome c oxidase (complex IV) that is reduced in post-mortem AD brains, and then investigated the role of Trx expression in response of neurons with mitochondrial dysfunction to oxidative stress. We found that neurons treated with sub-threshold concentration (8mM) of NaN(3) have mitochondrial dysfunction and that thioredoxin (Trx) mRNA and protein level decreased in neurons with mitochondrial dysfunction though no significant change in the viability. When exposed to extracellular H(2)O(2), neurons with mitochondrial dysfunction were significantly more vulnerable than control neurons. Trx mRNA and protein levels in neurons with mitochondrial dysfunction decreased in a dose- and time-dependent manner (mRNA: 25-150 microM H(2)O(2) for 1h and 50 microM H(2)O(2) for 1-3h; protein: 25-150 microM H(2)O(2) for 1h and 50 microM H(2)O(2) for 1-4h), while those in control neurons had no significant changes (50-250 microM H(2)O(2) for 1h). The data implied that vulnerability of neurons with mitochondrial dysfunction to oxidative stress is associated with down-regulation of thioredoxin.