TLR7 and IL-6 differentially regulate the effects of rotarod exercise on the transcriptomic profile and neurogenesis to influence anxiety and memory

Treadmill exercise modulates the medial prefrontal-amygdala neural circuit to improve the resilience against chronic restraint stress

Aerobic exercise effectively ameliorates mental disorders including anxiety and depression. Current findings mainly attribute its neural mechanism to the improvement of adult neurogenesis, while leaving the possible circuitry mechanism unclear. In the current study, we identify the overexcitation of the medial prefrontal cortex (mPFC) to basolateral amygdala (BLA) pathway under chronic restraint stress (CRS), and 14-day treadmill exercise selectively reverses such abnormalities. Using chemogenetic approaches, we find that the mPFC-BLA circuit is necessary for preventing anxiety-like behaviors in CRS mice. These results collectively suggest a neural circuitry mechanism by which exercise training improves the resilience against environmental stress.

Sex bias in social deficits, neural circuits and nutrient demand in Cttnbp2 autism models

Autism spectrum disorders caused by both genetic and environmental factors are strongly male-biased neuropsychiatric conditions. However, the mechanism underlying the sex bias of autism spectrum disorders remains elusive. Here, we use a mouse model in which the autism-linked gene Cttnbp2 is mutated to explore the potential mechanism underlying the autism sex bias. Autism-like features of Cttnbp2 mutant mice were assessed via behavioural assays. C-FOS staining identified sex-biased brain regions critical to social interaction, with their roles and connectivity then validated by chemogenetic manipulation. Proteomic and bioinformatic analyses established sex-biased molecular deficits at synapses, prompting our hypothesis that male-biased nutrient demand magnifies Cttnbp2 deficiency. Accordingly, intakes of branched-chain amino acids (BCAA) and zinc were experimentally altered to assess their effect on autism-like behaviours. Both deletion and autism-linked mutation of Cttnbp2 result in male-biased social deficits. Seven brain regions, including the infralimbic area of the medial prefrontal cortex (ILA), exhibit reduced neural activity in male mutant mice but not in females upon social stimulation. ILA activation by chemogenetic manipulation is sufficient to activate four of those brain regions susceptible to Cttnbp2 deficiency and consequently to ameliorate social deficits in male mice, implying an ILA-regulated neural circuit is critical to male-biased social deficits. Proteomics analysis reveals male-specific downregulated proteins (including SHANK2 and PSD-95, two synaptic zinc-binding proteins) and female-specific upregulated proteins (including RRAGC) linked to neuropsychiatric disorders, which are likely relevant to male-biased deficits and a female protective effect observed in Cttnbp2 mutant mice. Notably, RRAGC is an upstream regulator of mTOR that senses BCAA, suggesting that mTOR exerts a beneficial effect on females. Indeed, increased BCAA intake activates the mTOR pathway and rescues neuronal responses and social behaviours of male Cttnbp2 mutant mice. Moreover, mutant males exhibit greatly increased zinc demand to display normal social behaviours. Mice carrying an autism-linked Cttnbp2 mutation exhibit male-biased social deficits linked to specific brain regions, differential synaptic proteomes and higher demand for BCAA and zinc. We postulate that lower demand for zinc and BCAA are relevant to the female protective effect. Our study reveals a mechanism underlying sex-biased social defects and also suggests a potential therapeutic approach for autism spectrum disorders.

A novel protective modality against rotenone-induced Parkinson's disease: A pre-clinical study with dulaglutide

Parkinson's disease (PD) drugs treat symptoms without inhibiting progression. In recent years, finding novel therapeutic medications that can halt disease progression has become crucial. Research on antidiabetic medicines is valuable in these investigations because of the parallels between the two disorders. Using Rotenone (ROT), a frequently used PD model, the possible neuroprotective benefits of Dulaglutide (DUL), an extended-acting glucagon-like peptide-1 agonist, were considered. Twenty-four rats were randomly assigned to 4 groups to complete this experiment (n = 6). 0.2 ml of the vehicle (1 ml of dimethyl sulfoxide (DMSO) diluted in sunflower oil) was administered to the standard control group subcutaneously with a 48-hour pause. The second group was administered ROT 2.5 mg/kg SC every 48 h for 20 days as a positive control group. The third and fourth groups were administered one dose of DUL each week (0.05 and 0.1 mg/kg SC, respectively) to their regimens. The mice received ROT (2.5 mg/kg SC) every 48 h for 20 days after receiving DUL for the initial dose (96 h later). The current study focused on the DUL's ability to preserve usual behavioral function, enhance antioxidant and anti-inflammatory pathways, inhibit alpha-synuclein (α-syn), and increase parkin levels. It is concluded that DUL acts as an antioxidant and an anti-inflammatory to protect against ROT-induced PD. However, more studies are required to support this finding.

Rethinking Parkinson Disease: Exploring Gut-Brain Interactions and the Potential Role of Exercise

Although Parkinson disease (PD) has traditionally been considered a disease of the central nervous system, a bidirectional communication system known as the gut-brain axis can influence PD pathogenesis. The dual-hit hypothesis proposed that PD is due to peripheral dysregulations to the gut microbiota, known as dysbiosis. Since then, further investigation has shown that there are multiple pathological sources associated with PD. However, dysbiosis plays a critical role in the disease process. Substantial evidence has identified that cardinal motor symptoms of PD and disease progression are associated with dysbiosis. In other neurodegenerative disorders, dysbiosis has been linked to cognition. Non-PD research has shown that exercise can effectively restore the gut microbiota. Likewise, exercise has become a well-established strategy to improve cognitive and motor function in PD. However, despite the interaction between the gut and brain, and the exercise benefits on gut health, no research to date has considered the effects of exercise on the gut microbiota in PD. Therefore, the purpose of this Perspective is to explore whether exercise benefits observed in PD could partly be due to restorations to the gut microbiota. First, we will review the gut-brain axis and its influence on motor and cognitive function. Next, we will outline evidence regarding exercise-induced restoration of the gut microbiota in non-PD populations. Finally, we will summarize benefits of exercise on motor-cognitive function in PD, proposing that benefits of exercise seen in PD might actually be due to restorations to the gut microbiota. By positing the gut microbiota as a moderator of exercise improvements to motor and cognitive function, we aim to provide a new perspective for physical therapists to prioritize exercise regimens for individuals with PD that can specifically restore the gut microbiota to better improve PD symptoms and prognosis.

IMPACT

This Perspective raises awareness that dysregulations to the gut microbiota have recently been attributed to PD symptoms and pathology and that exercise can be an effective therapeutic strategy to improve gut health in individuals with PD.

LAY SUMMARY

People with PD have been found to have reduced microbial diversity in their gut, which can play an important role in the progression of the disease. Physical therapists can design therapeutic exercises that might help improve gut health in people with PD.