Endothelial ErbB4 deficit induces alterations in exploratory behavior and brain energy metabolism in mice

Present and future use of exosomes containing proteins and RNAs in neurodegenerative diseases for synaptic function regulation: A comprehensive review

Neurodegenerative diseases (NDDs) are increasingly prevalent with global aging, demanding effective treatments. Exosomes, which contain biological macromolecules such as RNA (including miRNAs) and proteins like α-synuclein, tau, and amyloid-beta, are gaining attention as innovative therapeutics. This comprehensive review systematically explores the potential roles of exosomes in NDDs, with a particular focus on their role in synaptic dysfunction. We present the synaptic pathophysiology of NDDs and discuss the mechanisms of exosome formation, secretion, and action. Subsequently, we review the roles of exosomes in different types of NDDs, such as Alzheimer's disease and Parkinson's disease, with a special focus on their regulation of synaptic function. In addition, we explore the potential use of exosomes as biomarkers, as well as the challenges and opportunities in their clinical application. We provide perspectives on future research directions and development trends to provide a more comprehensive understanding of and guidance for the application of exosomes in the treatment of NDDs. In conclusion, exosomes rich in biological macromolecules, as a novel therapeutic strategy, have opened up new possibilities for the treatment of NDDs and brought new hope to patients.

MicroRNA-23a-3p is upregulated in plasma exosomes of bulbar-onset ALS patients and targets ERBB4

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease related to the progressive death of motor neurons. Understanding the pathogenesis of ALS continues to provide considerable challenges. Bulbar-onset ALS involves faster functional loss and shorter survival time than spinal cord-onset ALS. However, debate is ongoing regarding typical plasma miRNA changes in ALS patients with bulbar onset. Exosomal miRNAs have not yet been described as a tool for bulbar-onset ALS diagnosis or prognosis prediction. In this study, candidate exosomal miRNAs were identified by small RNA sequencing using samples from patients with bulbar-onset ALS and healthy controls. Potential pathogenic mechanisms were identified through enrichment analysis of target genes for differential miRNAs. Expression of miR-16-5p, miR-23a-3p, miR-22-3p, and miR-93-5p was significantly up-regulated in plasma exosomes from bulbar-onset ALS patients compared with healthy control subjects. Among them, miR-16-5p and miR-23a-3p were significantly lower in spinal-onset ALS patients than those with bulbar-onset. Furthermore, up-regulation of miR-23a-3p in motor neuron-like NSC-34 cells promoted apoptosis and inhibited cell viability. This miRNA was found to directly target ERBB4 and regulate the AKT/GSK3β pathway. Collectively, the above miRNAs and their targets are related to the development of bulbar-onset ALS. Our research indicates that miR-23a-3p might have an effect on motor neuron loss observed in bulbar-onset ALS and may be a novel target for the therapy of ALS in the future.

Shared genetics of psychiatric disorders and type 2 diabetes:a large-scale genome-wide cross-trait analysis

BACKGROUND

Individuals with psychiatric disorders have elevated rates of type 2 diabetes comorbidity. Although little is known about the shared genetics and causality of this association. Thus, we aimed to investigate shared genetics and causal link between different type 2 diabetes and psychiatric disorders.

METHODS

We conducted a large-scale genome-wide cross-trait association study(GWAS) to investigate genetic overlap between type 2 diabetes and anorexia nervosa, attention deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, obsessive-compulsive disorder, schizophrenia, anxiety disorders and Tourette syndrome. By post-GWAS functional analysis, we identify variants genes expression in various tissues. Enrichment pathways, potential protein interaction and mendelian randomization also provided to research the relationship between type 2 diabetes and psychiatric disorders.

RESULTS

We discovered that type 2 diabetes and psychiatric disorders had a significant correlation. We identified 138 related loci, 32 were novel loci. Post-GWAS analysis revealed that 86 differentially expressed genes were located in different brain regions and peripheral blood in type 2 diabetes and related psychiatric disorders. MAPK signaling pathway plays an important role in neural development and insulin signaling. In addition, there is a causal relationship between T2D and mental disorders. In PPI analysis, the central genes of the DEG PPI network were FTO and TCF7L2.

CONCLUSION

This large-scale genome-wide cross-trait analysis identified shared genetics andpotential causal links between type 2 diabetes and related psychiatric disorders, suggesting potential new biological functions in common among them.

Structure, regulation, and biological functions of TIGAR and its role in diseases

TIGAR (TP53-induced glycolysis and apoptosis regulator) is the downstream target gene of p53, contains a functional sequence similar to 6-phosphofructose kinase/fructose-2, 6-bisphosphatase (PFKFB) bisphosphatase domain. TIGAR is mainly located in the cytoplasm; in response to stress, TIGAR is translocated to nucleus and organelles, including mitochondria and endoplasmic reticulum to regulate cell function. P53 family members (p53, p63, and p73), some transcription factors (SP1 and CREB), and noncoding miRNAs (miR-144, miR-885-5p, and miR-101) regulate the transcription of TIGAR. TIGAR mainly functions as fructose-2,6-bisphosphatase to hydrolyze fructose-1,6-diphosphate and fructose-2,6-diphosphate to inhibit glycolysis. TIGAR in turn facilitates pentose phosphate pathway flux to produce nicotinamide adenine dinucleotide phosphate (NADPH) and ribose, thereby promoting DNA repair, and reducing intracellular reactive oxygen species. TIGAR thus maintains energy metabolism balance, regulates autophagy and stem cell differentiation, and promotes cell survival. Meanwhile, TIGAR also has a nonenzymatic function and can interact with retinoblastoma protein, protein kinase B, nuclear factor-kappa B, hexokinase 2, and ATP5A1 to mediate cell cycle arrest, inflammatory response, and mitochondrial protection. TIGAR might be a potential target for the prevention and treatment of cardiovascular and neurological diseases, as well as cancers.

Role of pericyte-derived SENP1 in neuronal injury after brain ischemia

Aims

SUMOylation is a posttranslational modification related to multiple human diseases. SUMOylation can be reversed by classes of proteases known as the sentrin/SUMO‐specific proteases (SENPs). In the present study, we investigate the potential role of SENP1 in pericytes in the brain ischemia.

Methods

Pericyte‐specific deletion of senp1 mice (Cspg4‐Cre; senp1^f/f) were used for brain function and neuronal damage evaluation following brain ischemia. The cerebral blood vessels of diameter, velocity, and flux were performed in living mice by two‐photon laser scanning microscopy (TPLSM). Biochemical analysis and immunohistochemistry methods were used to address the role and mechanism of pericyte‐specific SENP1 in the pathological process of brain ischemia. A coculture model of HBVPs and HBMECs mimicked the BBB in vitro and was used to evaluate BBB integrity after glucose deprivation.

Results

Our results showed that senp1‐specific deletion in pericytes did not affect the motor function and cognitive function of mice. However, the pericyte‐specific deletion of senp1 aggravated the infarct size and motor deficit following focal brain ischemia. Consistently, the TPLSM data demonstrated that SENP1 deletion in pericytes accelerated thrombosis formation in brain microvessels. We also found that pericyte‐specific deletion of senp1 exaggerated the neuronal damage significantly following brain ischemia in mice. Moreover, SENP1 knockdown in pericytes could activate the apoptosis signaling and disrupt the barrier integrity in vitro coculture model.

Conclusions

Our findings revealed that targeting SENP1 in pericytes may represent a novel therapeutic strategy for neurovascular protection in stroke.

Cerebral microvascular dysfunction and neurodegeneration in dementia

Maintaining normal learning and memory functions requires a high degree of coordination between neural and vascular cells. Basic and clinical studies have shown that brain microvasculature dysfunction activates inflammatory cells in the brain, leading to progressive neuronal loss and eventually dementia. This review focuses on recent studies aimed at identifying the molecular events that link cerebral microvascular dysfunction to neurodegeneration, including oxidative/nitrosative stress, cellular metabolic dysfunction, inflammatory signalling and abnormal synaptic plasticity. A better understanding of the coupling between vasculature and brain neurons and how this coupling is disrupted under pathological conditions is of great significance in identifying new diagnostic and treatment targets for dementia for which no new drugs have been approved since 2003.

Endothelial ErbB4 deficit induces alterations in exploratory behavior and brain energy metabolism in mice

AIMS

The receptor tyrosine kinase ErbB4 is present throughout the primate brain and has a distinct functional profile. In this study, we investigate the potential role of endothelial ErbB4 receptor signaling in the brain.

RESULTS

Here, we show that the endothelial cell-specific deletion of ErbB4 induces decreased exploratory behavior in adult mice. However, the water maze task for spatial memory and the memory reconsolidation test reveal no changes; additionally, we observe no impairment in CaMKII phosphorylation in Cdh5Cre;ErbB4^f/f mice, which indicates that the endothelial ErbB4 deficit leads to decreased exploratory activity rather than direct memory deficits. Furthermore, decreased brain metabolism, which was measured using micro-positron emission tomography, is observed in the Cdh5Cre;ErbB4^f/f mice. Consistently, the immunoblot data demonstrate the downregulation of brain Glut1, phospho-ULK1 (Ser555), and TIGAR in the endothelial ErbB4 conditional knockout mice. Collectively, our findings suggest that endothelial ErbB4 plays a critical role in regulating brain function, at least in part, through maintaining normal brain energy homeostasis.

CONCLUSIONS

Targeting ErbB4 or the modulation of endothelial ErbB4 signaling may represent a rational pharmacological approach to treat neurological disorders.