VCP-Mediated Autophagy Enhancement

Mitophagy is an essential mitochondrial quality control mechanism that eliminates damaged mitochondria and the production of reactive oxygen species (ROS). The relationship between mitochondria oxidative stress, ROS production and mitophagy are intimately interwoven, and these processes are all involved in various pathological conditions of acute kidney injury (AKI). The elimination of damaged mitochondria through mitophagy in mammals is a complicated process which involves several pathways. Furthermore, the interplay between mitophagy and different types of cell death, such as apoptosis, pyroptosis and ferroptosis in kidney injury is unclear. Here we will review recent advances in our understanding of the relationship between ROS and mitophagy, the different mitophagy pathways, the relationship between mitophagy and cell death, and the relevance of these processes in the pathogenesis of AKI.Abbreviations: AKI: acute kidney injury; AMBRA1: autophagy and beclin 1 regulator 1; ATP: adenosine triphosphate; BAK1: BCL2 antagonist/killer 1; BAX: BCL2 associated X, apoptosis regulator; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BH3: BCL2 homology domain 3; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; CASP1: caspase 1; CAT: catalase; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CI-AKI: contrast-induced acute kidney injury; CISD1: CDGSH iron sulfur domain 1; CL: cardiolipin; CNP: 2',3'-cyclic nucleotide 3'-phosphodiesterase; DNM1L/DRP1: dyna

Macroautophagy/autophagy is essential for the degradation and recycling of cytoplasmic materials. The initiation of this process is determined by phosphatidylinositol-3-kinase (PtdIns3K) complex, which is regulated by factor BECN1 (beclin 1). UFMylation is a novel ubiquitin-like modification that has been demonstrated to modulate several cellular activities. However, the role of UFMylation in regulating autophagy has not been fully elucidated. Here, we found that VCP/p97 is UFMylated on K109 by the E3 UFL1 (UFM1 specific ligase 1) and this modification promotes BECN1 stabilization and assembly of the PtdIns3K complex, suggesting a role for VCP/p97 UFMylation in autophagy initiation. Mechanistically, VCP/p97 UFMylation stabilizes BECN1 through ATXN3 (ataxin 3)-mediated deubiquitination. As a key component of the PtdIns3K complex, stabilized BECN1 facilitates assembly of this complex. Re-expression of VCP/p97, but not the UFMylation-defective mutant, rescued the VCP/p97 depletion-induced increase in MAP1LC3B/LC3B protein expression. We also showed that several pathogenic VCP/p97 mutations identified in a variety of neurological disorders and cancers were associated with reduced UFMylation, thus implicating VCP/p97 UFMylation as a potential therapeutic target for these diseases. Abbreviation: ATG14:autophagy related 14; Baf A1:bafilomycin A1;CMT2Y: Charcot-Marie-Toothdisease, axonal, 2Y; CYB5R3: cytochromeb5 reductase 3; DDRGK1: DDRGK domain containing 1; DMEM:Dulbecco'smodified

Mechanisms of protein homeostasis are crucial for overseeing the clearance of misfolded and toxic proteins over the lifetime of an organism, thereby ensuring the health of neurons and other cells of the central nervous system. The highly conserved pathway of autophagy is particularly necessary for preventing and counteracting pathogenic insults that may lead to neurodegeneration. In line with this, mutations in genes that encode essential autophagy factors result in impaired autophagy and lead to neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS). However, the mechanistic details underlying the neuroprotective role of autophagy, neuronal resistance to autophagy induction, and the neuron-specific effects of autophagy-impairing mutations remain incompletely defined. Further, the manner and extent to which non-cell autonomous effects of autophagy dysfunction contribute to ALS pathogenesis are not fully understood. Here, we review the current understanding of the interplay between autophagy and ALS pathogenesis by providing an overview of critical steps in the autophagy pathway, with special focus on pivotal factors impaired by ALS-causing mutations, their physiologic effects on autophagy in disease models, and the cell type-specific mechanisms regulating autophagy in non-neuronal cells which, when impaired, can contribute to neurodegeneration. This review thereby provides a framework not only to guide further investigations of neuronal autophagy but also to

Phosphoglycerate kinase 1 (PGK1) is traditionally recognized for its pivotal role in glycolysis. Our findings reveal that PGK1 also functions as a protein kinase phosphorylating valosin-containing protein (VCP) at S746, which subsequently reduces Beclin 1 deubiquitination and impairs autophagy. Inhibition of PGK1 initiates autophagy in T315I-mutant chronic myeloid leukemia (CML) cells, thereby enhancing their sensitivity to first-generation Tyrosine Kinase Inhibitor (TKI) imatinib and third-generation TKI ponatinib. Despite the significant clinical implications, few PGK1-targeting inhibitors have been approved for clinical use to date. Through a comprehensive high-throughput screening of ∼20,000 natural compounds, we identified flavonoid as potent inhibitors of the enzymatic activity of PGK1. Subsequent structural optimization of these flavonoid derivatives led to the development of CPU-216, a compound that binds to the GLU344 and PHE292 residues of PGK1, effectively inhibiting its enzymatic and kinase activity. Notably, CPU-216 induces autophagy via VCP and Beclin 1 in CML-T315I cells, enhancing their responsiveness to TKIs. These discoveries propose a novel therapeutic strategy for T315I-mutant CML, underscoring the potential to develop targeted treatments that leverage the kinase functions of PGK1.

PINK1 is a master regulator of PINK1-parkin-mediated mitophagy, a key process for maintaining mitochondrial homeostasis. The precise regulation of PINK1 is therefore essential for orchestrating mitophagy. While proteolytic processing of PINK1 and degradation of cleaved PINK1 via the N-end rule under basal conditions have been extensively characterized, the mechanisms governing full-length PINK1 degradation upon mitochondrial damage remain enigmatic. Here, we demonstrate that PINK1 undergoes ubiquitination and proteasomal degradation during mitophagy through the coordinated action of STUB1 and VCP/p97. Depletion of STUB1 stabilizes full-length PINK1, which paradoxically impairs mitophagy through the acceleration of parkin degradation. At the organismal level, the STUB1-VCP axis plays an important role in neuronal mitophagy-related memory and learning capacities in the roundworm C. elegans. Congruently, this axis is impaired in the postmortem brain tissues from patients with Alzheimer's disease compared with cognitively normal controls. Collectively, our findings support STUB1-VCP as a molecular calibrator that fine-tunes full-length PINK1 levels to enable efficient mitophagy and maintain mitochondrial homeostasis.

p97, also known as valosin-containing protein (VCP), is an evolutionarily conserved ATPase that functions upstream of the two major protein degradation pathways: the ubiquitin-proteasome system (UPS) and autophagy. In this capacity, it plays a central role in maintaining protein homeostasis and genome stability. The roles of the UPS and autophagy in regulating immune responses including within the tumour microenvironment (TME), are well established. However, the contribution of p97 to shaping immune responses in the TME has only recently begun to emerge. Recent findings indicate that p97 not only affects cancer cells directly but also plays a critical role in the heterogeneous TME, acting as a key driver of tumour progression, therapy resistance, and metastatic initiation. In this review, we will discuss the role of the p97 system in tumour immunity. A deeper understanding of how p97 regulates immune responses is essential for advancing cancer biology and oncology.

Tauopathies are a diverse group of progressive and fatal neurodegenerative diseases characterized by aberrant tau inclusions in the central nervous system. Tau protein forms pathologic fibrillar aggregates that are typically closely associated with neuronal cell death, leading to varied clinical phenotypes including dementia, movement disorders, and motor neuron disease. In this review, we describe the clinicopathologic features of tauopathies and highlight recent advances in understanding the mechanisms that lead to spread of pathologic aggregates through interconnected neuronal pathways. The cell-to-cell propagation of tauopathy is then linked to posttranslational modifications, tau fibril structural variants, and the breakdown of cellular protein quality control.

Mechanisms of protein homeostasis are crucial for overseeing the clearance of misfolded and toxic proteins over the lifetime of an organism, thereby ensuring the health of neurons and other cells of the central nervous system. The highly conserved pathway of autophagy is particularly necessary for preventing and counteracting pathogenic insults that may lead to neurodegeneration. In line with this, mutations in genes that encode essential autophagy factors result in impaired autophagy and lead to neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS). However, the mechanistic details underlying the neuroprotective role of autophagy, neuronal resistance to autophagy induction, and the neuron-specific effects of autophagy-impairing mutations remain incompletely defined. Further, the manner and extent to which non-cell autonomous effects of autophagy dysfunction contribute to ALS pathogenesis are not fully understood. Here, we review the current understanding of the interplay between autophagy and ALS pathogenesis by providing an overview of critical steps in the autophagy pathway, with special focus on pivotal factors impaired by ALS-causing mutations, their physiologic effects on autophagy in disease models, and the cell type-specific mechanisms regulating autophagy in non-neuronal cells which, when impaired, can contribute to neurodegeneration. This review thereby provides a framework not only to guide further investigations of neuronal autophagy but also to

Axonal beading is a key morphological indicator of axonal degeneration, which plays a significant role in various neurodegenerative diseases and drug-induced neuropathies. Quantification of axonal susceptibility to beading using neuronal cell culture can be used as a facile assay to evaluate induced degenerative conditions, and thus aid in understanding mechanisms of beading and in drug development. Manual analysis of axonal beading for large datasets is labor-intensive and prone to subjectivity, limiting the reproducibility of results. To address these challenges, we developed a semi-automated Python-based tool to track axonal beading in time-lapse microscopy images. The software significantly reduces human effort by detecting the onset of axonal swelling. Our method is based on classical image processing techniques rather than an AI approach. This provides interpretable results while allowing the extraction of additional quantitative data, such as bead density, coarsening dynamics, and morphological changes over time. Comparison of results obtained through human analysis and the software shows strong agreement. The code can be easily extended to analyze diameter information of ridge-like structures in branched networks of rivers, road networks, blood vessels, etc.

Background and Objectives: Vernix caseosa peritonitis (VCP) is rare. Nonspecific symptoms of acute abdomen during early puerperium make preoperative diagnosis of VCP challenging. We aimed to identify risk factors, early diagnosis and treatment options, and the association between the timing and severity of VCP diagnosis and maternal outcomes. Materials and Methods: We searched PubMed, PubMed Central, and Google Scholar. Articles were analyzed according to the PRISMA guidelines. The search items included: 'vernix caseosa peritonitis, 'vernix caseosa granuloma, 'maternal meconium peritonitis', 'maternal meconium granuloma', 'vernix caseosa', 'peritonitis', 'pregnancy', 'puerperium', 'postpartum', and 'gravid'. Additional studies were extracted by reviewing the reference lists of retrieved studies. Demographic, clinical, obstetric, diagnostic, and treatment parameters, and outcomes were collected. Results: Out of 55 published VCP case reports, 46 were available. Most involved term pregnancies (84.8%) and were delivered by Cesarean section (CS) (87%), with no difference in parity distribution (χ2(2) = 1.1875, p = 0.5523) or fetal sex (m: f = 53.3%: 46.7%). Common symptoms included abdominal pain and fever over 38 °C, while dyspnea or tachypnea was unexpectedly frequent (23.9%/15.2%). The interval from delivery to surgery ranged from 4 to 13 days (average 8 days), with no difference between CS and vaginal deliveries. Preoperative VCP was diagnosed in only 4.3% of cases, and intrao