Melatonin-mediated FKBP4 downregulation protects against stress-induced neuronal mitochondria dysfunctions by blocking nuclear translocation of GR

Progress in the regulatory mechanism of mitophagy in chronic cerebral ischemic neuronal injury

Chronic cerebral ischemia (CCI) is a common clinical syndrome that can impact various cerebrovascular diseases. Its pathological mechanism of injury involves energy imbalance, oxidative stress, inflammatory response, and many other processes. Neuronal damage occurs in a complex and multifaceted manner. This article provides a detailed discussion of the activation and inhibition mechanisms of mitophagy under cerebral ischemia and considers the advantages and disadvantages of mitophagy in the recovery process of ischemic brain injury. Finally, we address the future direction of research on neuronal injury and the regulatory mechanisms of mitophagy in chronic cerebral ischemia. Future studies should focus on drug intervention at specific regulatory points and the cross-regulation of related signaling pathways to comprehensively deepen understanding of the mechanisms of neuronal injury in chronic cerebral ischemia. Promising interventions could potentially improve the treatment and outcomes of chronic cerebral ischemia.

Self-Healing COCu-Tac Hydrogel Enhances iNSCs Transplantation for Spinal Cord Injury by Promoting Mitophagy via the FKBP52/AKT Pathway

In the realm of neural regeneration post-spinal cord injury, hydrogel scaffolds carrying induced neural stem cells (iNSCs) have demonstrated significant potential. However, challenges such as graft rejection and dysfunction caused by mitochondrial damage persist after transplantation, presenting formidable barriers. Tacrolimus, known for its dual role as an immunosuppressant and promoter of neural regeneration, holds the potential for enhancing iNSC transplantation. However, systemic administration of tacrolimus often comes with severe side effects. This study pioneers the development of a self-healing hydrogel with sustained-release tacrolimus (COCu-Tac), tailored specifically for iNSC transplantation after spinal cord injury. This research reveals that the sustained release of tacrolimus enhances axonal growth and improves mitochondrial quality control in iNSCs and neurons. Further analysis shows that tacrolimus targets FKBP52 rather than FKBP51, enhancing mitophagy via the FKBP52/AKT pathway. This advanced system demonstrates significant efficacy in promoting neural regeneration and restoring motor function following spinal cord injury.

Melatonin Protects Against Cocaine-Induced Blood-Brain Barrier Dysfunction and Cognitive Impairment by Regulating miR-320a-Dependent GLUT1 Expression

Cocaine abuse has been strongly linked to blood-brain barrier (BBB) dysfunction, though the exact mechanism by which cocaine disrupts the BBB remains unclear. In this study, we found that cocaine treatment reduces the expression of glucose transporter 1 (GLUT1) in brain microvascular endothelial cells, a key factor in cocaine-induced brain glucose uptake, BBB leakage, and cognitive impairment. Mechanistically, our results show that cocaine upregulates miR-320a, which in turn suppresses GLUT1 expression via the beta 2-adrenergic receptor (ADRB2). Notably, the administration of adeno-associated viruses encoding full-length GLUT1 or miR-320a inhibitors to the brain microvascular endothelium significantly mitigated cocaine-induced BBB leakage and cognitive deficits. Additionally, we discovered that melatonin, a well-known neuroprotective hormone, alleviates cocaine-induced BBB disruption and cognitive impairment. This protective effect of melatonin was mediated through the upregulation of miR-320a-dependent GLUT1 expression in brain endothelial cells via MT1 receptor-mediated inhibition of the cAMP/PKA/CREB signaling pathway. In conclusion, our findings demonstrate that cocaine downregulates brain microvascular GLUT1, leading to BBB dysfunction, and highlight melatonin as a potential therapeutic agent for treating cocaine-related complications.

Modulation of autophagy by melatonin and its receptors: implications in brain disorders

Autophagy plays a crucial role in maintaining neuronal homeostasis and function, and its disruption is linked to various brain diseases. Melatonin, an endogenous hormone that primarily acts through MT1 and MT2 receptors, regulates autophagy via multiple pathways. Growing evidence indicates that melatonin's ability to modulate autophagy provides therapeutic and preventive benefits in brain disorders, including neurodegenerative and affective diseases. In this review, we summarize the key mechanisms by which melatonin affects autophagy and explore its therapeutic potential in the treatment of brain disorders.

Secretome Analyses Identify FKBP4 as a GBA1-Associated Protein in CSF and iPS Cells from Parkinson's Disease Patients with GBA1 Mutations

Mutations in the GBA1 gene increase the risk of developing Parkinson's disease (PD). However, most carriers of GBA1 mutations do not develop PD throughout their lives. The mechanisms of how GBA1 mutations contribute to PD pathogenesis remain unclear. Cerebrospinal fluid (CSF) is used for detecting pathological conditions of diseases, providing insights into the molecular mechanisms underlying neurodegenerative disorders. In this study, we utilized the proximity extension assay to examine the levels of metabolism-linked protein in the CSF from 17 PD patients carrying GBA1 mutations (GBA1-PD) and 17 idiopathic PD (iPD). The analysis of CSF secretome in GBA1-PD identified 11 significantly altered proteins, namely FKBP4, THOP1, GLRX, TXNDC5, GAL, SEMA3F, CRKL, APLP1, LRP11, CD164, and NPTXR. To investigate GBA1-associated CSF changes attributed to specific neuronal subtypes responsible for PD, we analyzed the cell culture supernatant from GBA1-PD-induced pluripotent stem cell (iPSC)-derived midbrain dopaminergic (mDA) neurons. The secretome analysis of GBA1-PD iPSC-derived mDA neurons revealed that five differently regulated proteins overlapped with those identified in the CSF analysis: FKBP4, THOP1, GLRX, GAL, and CRKL. Reduced intracellular level of the top hit, FKPB4, was confirmed via Western Blot. In conclusion, our findings identify significantly altered CSF GBA1-PD-associated proteins with FKPB4 being firmly attributed to mDA neurons.

Melatonin, BAG-1 and cortisol circadian interactions in tumor pathogenesis and patterned immune responses

A dysregulated circadian rhythm is significantly associated with cancer risk, as is aging. Both aging and circadian dysregulation show suppressed pineal melatonin, which is indicated in many studies to be linked to cancer risk and progression. Another independently investigated aspect of the circadian rhythm is the cortisol awakening response (CAR), which is linked to stress-associated hypothalamus-pituitary-adrenal (HPA) axis activation. CAR and HPA axis activity are primarily mediated via activation of the glucocorticoid receptor (GR), which drives patterned gene expression via binding to the promotors of glucocorticoid response element (GRE)-expressing genes. Recent data shows that the GR can be prevented from nuclear translocation by the B cell lymphoma-2 (Bcl-2)-associated athanogene 1 (BAG-1), which translocates the GR to mitochondria, where it can have diverse effects. Melatonin also suppresses GR nuclear translocation by maintaining the GR in a complex with heat shock protein 90 (Hsp90). Melatonin, directly and/or epigenetically, can upregulate BAG-1, suggesting that the dramatic 10-fold decrease in pineal melatonin from adolescence to the ninth decade of life will attenuate the capacity of night-time melatonin to modulate the effects of the early morning CAR. The interactions of pineal melatonin/BAG-1/Hsp90 with the CAR are proposed to underpin how aging and circadian dysregulation are associated with cancer risk. This may be mediated via differential effects of melatonin/BAG-1/Hsp90/GR in different cells of microenvironments across the body, from which tumors emerge. This provides a model of cancer pathogenesis that better integrates previously disparate bodies of data, including how immune cells are regulated by cancer cells in the tumor microenvironment, at least partly via the cancer cell regulation of the tryptophan-melatonin pathway. This has a number of future research and treatment implications.

Glucocorticoid receptor-mediated Nr1d1 chromatin circadian misalignment in stress-induced irritable bowel syndrome

Stress-elevated glucocorticoids cause circadian disturbances and gut-brain axis (GBA) disorders, including irritable bowel syndrome (IBS). We hypothesized that the glucocorticoid receptor (GR/NR3C1) might cause chromatin circadian misalignment in the colon epithelium. We observed significantly decreased core circadian gene Nr1d1 in water avoidance stressed (WAS) BALB/c colon epithelium, like in IBS patients. WAS decreased GR binding at the Nr1d1 promoter E-box (enhancer box), and GR could suppress Nr1d1 via this site. Stress also altered GR binding at the E-box sites along the Ikzf3-Nr1d1 chromatin and remodeled circadian chromatin 3D structures, including Ikzf3-Nr1d1 super-enhancer, Dbp, and Npas2. Intestinal deletion of Nr3c1 specifically abolished these stress-induced transcriptional alternations relevant to IBS phenotypes in BALB/c mice. GR mediated Ikzf3-Nr1d1 chromatin disease related circadian misalignment in stress-induced IBS animal model. This animal model dataset suggests that regulatory SNPs of human IKZF3-NR1D1 transcription through conserved chromatin looping have translational potential based on the GR-mediated circadian-stress crosstalk.