Serine Racemase mediates subventricular zone neurogenesis via fatty acid metabolism

Dandouchi Polypeptide Alleviates Depressive-like Behavior and Promotes Hippocampal Neurogenesis by Activating the TRIM67/NF-κB Pathway in CUMS-Induced Mice

Background: Dandouchi polypeptide (DDCP) is derived from Semen Sojae Praeparatum (Dandouchi in Chinese), a fermented product of Glycine max (L.) Merr. Semen Sojae Praeparatum is widely used in the food industry for its unique flavor and nutritional value, and DDCP, as its derivative, also shows potential health benefits in food applications. However, the specific active substances responsible for Semen Sojae Praeparatum and the underlying mechanisms involved have not been fully elucidated. Methods: DDCP was extracted from Semen Sojae Praeparatum using enzymes, and its antidepressant effects were tested in chronic unpredictable mild stress (CUMS)-induced mice. Immunohistochemistry, immunofluorescence, and western blotting were used to analyze neurogenesis and the nuclear factor κB (NF-κB) pathway. Moreover, an adeno-associated virus (AAV) shRNA was used to induce tripartite motif-containing 67 (TRIM67) deficiency to examine the function of TRIM67 in the neuroprotective effects of DDCP in depressive disorders. Results: DDCP reduced depressive behaviors in CUMS mice and the expression of proinflammatory markers in the hippocampus. DDCP promoted neurogenesis and modulated the TRIM67/NF-κB pathway, with TRIM67 deficiency impairing its antidepressant effect. Conclusions: This research revealed that DDCP has a protective effect on countering depression triggered by CUMS. Notably, TRIM67 plays a crucial role in mitigating depression through DDCP, positioning DDCP as a potential therapeutic option for treating depressive disorders.

Astrocytes in functional recovery following central nervous system injuries

Astrocytes are increasingly recognised as partaking in complex homeostatic mechanisms critical for regulating neuronal plasticity following central nervous system (CNS) insults. Ischaemic stroke and traumatic brain injury are associated with high rates of disability and mortality. Depending on the context and type of injury, reactive astrocytes respond with diverse morphological, proliferative and functional changes collectively known as astrogliosis, which results in both pathogenic and protective effects. There is a large body of research on the negative consequences of astrogliosis following brain injuries. There is also growing interest in how astrogliosis might in some contexts be protective and help to limit the spread of the injury. However, little is known about how astrocytes contribute to the chronic functional recovery phase following traumatic and ischaemic brain insults. In this review, we explore the protective functions of astrocytes in various aspects of secondary brain injury such as oedema, inflammation and blood-brain barrier dysfunction. We also discuss the current knowledge on astrocyte contribution to tissue regeneration, including angiogenesis, neurogenesis, synaptogenesis, dendrogenesis and axogenesis. Finally, we discuss diverse astrocyte-related factors that, if selectively targeted, could form the basis of astrocyte-targeted therapeutic strategies to better address currently untreatable CNS disorders.

Melatonin mitigates manganese-induced neural damage via modulation of gut microbiota-metabolism in mice

Manganese (Mn), a common environmental and occupational risk factor for Parkinson's disease (PD), can cause central nervous system damage and gastrointestinal dysfunction. The melatonin has been shown to effectively improve neural damage and intestinal microbiota disturbances in animal models. This research investigated the mechanism by which exogenous melatonin prevented Mn-induced neurogenesis impairment and neural damage. Here, we established subchronic Mn-exposed mice model and melatonin supplement tests to evaluate the role of melatonin in alleviating Mn-induced neurogenesis impairment. Mn induced neurogenesis impairment and microglia overactivation, behavioral dysfunction, gut microbiota dysbiosis and serum metabolic disorder in mice. All these events were reversed with the melatonin supplement. The behavioral tests revealed that melatonin group showed approximately 30 % restoration of motor activity. According to quantitative real time polymerase chain reaction (qPCR) results, melatonin group showed remarkable restoration of the expression of dopamine neurons and neurogenesis markers, approximately 46.4 % (TH), 68.4 % (DCX in hippocampus) and 48 % (DCX in striatum), respectively. Interestingly, melatonin increased neurogenesis probably via the gut microbiota and metabolism modulation. The correlation analysis of differentially expressed genes associated with hippocampal neurogenesis indicated that Firmicutes-lipid metabolism might mediate the critical repair role of melatonin in neurogenesis in Mn-exposed mice. In conclusion, exogenous melatonin supplementation can promote neurogenesis, and restore neuron loss and neural function in Mn-exposed mice, and the multi-omics results provide new research ideas for future mechanistic studies.

Lipidomics Profiling of Metformin-Induced Changes in Obesity and Type 2 Diabetes Mellitus: Insights and Biomarker Potential

Metformin is the first-line oral medication for treating type 2 diabetes mellitus (T2DM). In the current study, an untargeted lipidomic analytical approach was used to investigate the alterations in the serum lipidome of a cohort of 89 participants, including healthy lean controls and obese diabetic patients, and to examine the alterations associated with metformin administration. A total of 115 lipid molecules were significantly dysregulated (64 up-regulated and 51 down-regulated) in the obese compared to lean controls. However, the levels of 224 lipid molecules were significantly dysregulated (125 up-regulated and 99 down-regulated) in obese diabetic patients compared to the obese group. Metformin administration in obese diabetic patients was associated with significant dysregulation of 54 lipid molecule levels (20 up-regulated and 34 down-regulated). Levels of six molecules belonging to five lipid subclasses were simultaneously dysregulated by the effects of obesity, T2DM, and metformin. These include two putatively annotated triacylglycerols (TGs), one plasmenyl phosphatidylcholine (PC), one phosphatidylglycerol (PGs), one sterol lipid (ST), and one Mannosyl-phosphoinositol ceramide (MIPC). This study provides new insights into our understanding of the lipidomics alterations associated with obesity, T2DM, and metformin and offers a new platform for potential biomarkers for the progression of diabetes and treatment response in obese patients.

d-Amino acids: new clinical pathways for brain diseases

Free d-amino acids (d-AAs) are emerging as a novel and important class of signaling molecules in many organs, including the brain and endocrine systems. There has been considerable progress in our understanding of the fundamental roles of these atypical messengers, with increasingly recognized implications in a wide range of neuropathologies, including schizophrenia (SCZ), epilepsy, Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), substance abuse, and chronic pain, among others. Research has enabled the discovery that d-serine, d-aspartate and more recently d-cysteine are essential for the healthy development and function of the central nervous system (CNS). We discuss recent progress that has profoundly transformed our vision of numerous physiological processes but has also shown how d-AAs are now offering therapeutic promise in clinical settings for several human diseases.