HtrA2 regulates α-Synuclein-mediated mitochondrial reactive oxygen species production in the mitochondria of microglia

Mitochondria at the crossroads: Quality control mechanisms in neuronal senescence and neurodegeneration

Mitochondria play a central role in essential cellular processes, including energy metabolism, biosynthesis of metabolic substances, calcium ion storage, and regulation of cell death. Maintaining mitochondrial quality control is critical for preserving mitochondrial health and ensuring cellular function. Given their high energy demands, neurons depend on effective mitochondrial quality control to sustain their health and functionality. Neuronal senescence, characterized by a progressive decline in structural integrity and function, is a hallmark of neurodegenerative diseases. In senescent neurons, abnormal mitochondrial morphology, functional impairments, increased reactive oxygen species production and disrupted quality control mechanisms are frequently observed. Understanding the pathological changes in neuronal structure, exploring the intricate relationship between mitochondrial quality control and neuronal health, and leveraging mitochondrial quality control interventions provide a promising foundation for addressing age-related neurodegenerative diseases. This review highlights key mitochondrial quality control, including biogenesis, dynamics, the ubiquitin-proteasome system, autophagy pathways, mitochondria-derived vesicles, and inter-organelle communication, while discussing their roles in neuronal senescence and potential therapeutic strategies. These insights may pave the way for innovative treatments to mitigate neurodegenerative disorders.

N-Terminal Proteomics Reveals Distinct Protein Degradation Patterns in Different Types of Human Atherosclerotic Plaques

Atherosclerotic plaque rupture is a major cause of cardiovascular events. Plaque destabilization is associated with extracellular matrix (ECM) modification involving proteases which generate protein fragments with new N-termini. We hypothesized that rupture-prone plaques would contain elevated fragment levels, and their sequences would allow identification of active proteases and target proteins. Plaques from 21 patients who underwent surgery for symptomatic carotid artery stenosis were examined in an observational/cross-sectional study. Plaques were analyzed by liquid chromatography-mass spectrometry for the presence of N-terminal fragments. 33920 peptides were identified, with 17814 being N-terminal species. 5735 distinct N-terminal peptides were quantified and subjected to multidimensional scaling analysis and consensus clustering. These analyses indicated three clusters, which correlate with gross macroscopic plaque morphology (soft/mixed/hard), ultrasound classification (echolucent/echogenic), and the presence of hemorrhage/ulceration. Differences in the fragment complements are consistent with plaque-type-dependent turnover and degradation pathways. Identified peptides include signal and pro-peptides from synthesis and those from protein fragmentation. Sequence analysis indicates that targeted proteins include ECM species and responsible proteases (meprins, cathepsins, matrix metalloproteinases, elastase, and kallikreins). This study provides a large data set of peptide fragments and proteases present in plaques of differing stability. These species may have potential as biomarkers for improved atherosclerosis risk profiling.

Proteins in scalp hair of preschool children

Background

(1)Early childhood experiences have long-lasting effects on subsequent mental and physical health, education, and employment. Measurement of these effects relies on insensitive behavioral signs, subjective assessments by adult observers, neuroimaging or neurophysiological studies, or retrospective epidemiologic outcomes. Despite intensive search, the underlying mechanisms for these long-term changes in development and health status remain unknown.

Methods

(2)We analyzed scalp hair from healthy children and their mothers using an unbiased proteomics platform using tandem mass spectrometry, ultra-performance liquid chromatography, and collision induced dissociation to reveal commonly observed hair proteins with spectral count of 3 or higher.

Results

(3)We observed 1368 non-structural hair proteins in children, 1438 non-structural hair proteins in mothers, with 1288 proteins showing individual variability. Mothers showed higher numbers of peptide spectral matches and hair proteins compared to children, with important age-related differences between mothers and children. Age-related differences were also observed in children, with differential protein expression patterns between younger (2 years and below) and older children (3-5 years). We observed greater similarity in hair protein patterns between mothers and their biological children as compared to mothers and unrelated children. The top 5% proteins driving population variability represent biological pathways associated with brain development, immune signaling, and stress response regulation.

Conclusion

(4)Non-structural proteins observed in scalp hair include promising biomarkers to investigate the long-term developmental changes and health status associated with early childhood experiences.

HTRA2/OMI-Mediated Mitochondrial Quality Control Alters Macrophage Polarization Affecting Systemic Chronic Inflammation

Systemic chronic inflammation (SCI) due to intrinsic immune over-activation is an important factor in the development of many noninfectious chronic diseases, such as neurodegenerative diseases and diabetes mellitus. Among these immune responses, macrophages are extensively involved in the regulation of inflammatory responses by virtue of their polarization plasticity; thus, dysregulation of macrophage polarization direction is one of the potential causes of the generation and maintenance of SCI. High-temperature demand protein A2 (HtrA2/Omi) is an important regulator of mitochondrial quality control, not only participating in the degradation of mis-accumulated proteins in the mitochondrial unfolded protein response (UPRmt) to maintain normal mitochondrial function through its enzymatic activity, but also participating in the regulation of mitochondrial dynamics-related protein interactions to maintain mitochondrial morphology. Recent studies have also reported the involvement of HtrA2/Omi as a novel inflammatory mediator in the regulation of the inflammatory response. HtrA2/Omi regulates the inflammatory response in BMDM by controlling TRAF2 stabilization in a collagen-induced arthritis mouse model; the lack of HtrA2 ameliorates pro-inflammatory cytokine expression in macrophages. In this review, we summarize the mechanisms by which HtrA2/Omi proteins are involved in macrophage polarization remodeling by influencing macrophage energy metabolism reprogramming through the regulation of inflammatory signaling pathways and mitochondrial quality control, elucidating the roles played by HtrA2/Omi proteins in inflammatory responses. In conclusion, interfering with HtrA2/Omi may become an important entry point for regulating macrophage polarization, providing new research space for developing HtrA2/Omi-based therapies for SCI.

Advancements in Genetic and Biochemical Insights: Unraveling the Etiopathogenesis of Neurodegeneration in Parkinson's Disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative movement disorder worldwide, which is primarily characterized by motor impairments. Even though multiple hypotheses have been proposed over the decades that explain the pathogenesis of PD, presently, there are no cures or promising preventive therapies for PD. This could be attributed to the intricate pathophysiology of PD and the poorly understood molecular mechanism. To address these challenges comprehensively, a thorough disease model is imperative for a nuanced understanding of PD's underlying pathogenic mechanisms. This review offers a detailed analysis of the current state of knowledge regarding the molecular mechanisms underlying the pathogenesis of PD, with a particular emphasis on the roles played by gene-based factors in the disease's development and progression. This study includes an extensive discussion of the proteins and mutations of primary genes that are linked to PD, including α-synuclein, GBA1, LRRK2, VPS35, PINK1, DJ-1, and Parkin. Further, this review explores plausible mechanisms for DAergic neural loss, non-motor and non-dopaminergic pathologies, and the risk factors associated with PD. The present study will encourage the related research fields to understand better and analyze the current status of the biochemical mechanisms of PD, which might contribute to the design and development of efficacious and safe treatment strategies for PD in future endeavors.

Insights of Chinese herbal medicine for mitochondrial dysfunction in chronic cerebral hypoperfusion induced cognitive impairment: Existed evidences and potential directions

Chronic cerebral hypoperfusion (CCH) is one of the main pathophysiological markers of cognitive impairment in central nervous system diseases. Mitochondria are cores of energy generation and information process. Mitochondrial dysfunction is the key upstream factors of CCH induced neurovascular pathology. Increasing studies explored the molecular mechanisms of mitochondrial dysfunction and self-repair for effective targets to improve CCH-related cognitive impairment. The clinical efficacy of Chinese herbal medicine in the treatment of CCH induced cognitive impairment is definite. Existed evidences from pharmacological studies have further proved that, Chinese herbal medicine could improve mitochondrial dysfunction and neurovascular pathology after CCH by preventing calcium overload, reducing oxidative stress damage, enhancing antioxidant capacity, inhibiting mitochondria-related apoptosis pathway, promoting mitochondrial biogenesis and preventing excessive activation of mitophagy. Besides, CCH mediated mitochondrial dysfunction is one of the fundamental causes for neurodegeneration pathology aggravation. Chinese herbal medicine also has great potential therapeutic value in combating neurodegenerative diseases by targeting mitochondrial dysfunction.