Search Results (115)

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders among the elderly. The exact etiology of sporadic PD is still unknown; however, there is general consensus that the accumulation and aggregation of α-synuclein (α-syn) are among the prominent pathological features. The precise function of α-syn in the healthy human brain is not agreed upon, although it has been reported to play a role in vesicular trafficking and neurotransmitter release. Dutch Juvenile-1 (DJ-1) is a multifunctional protein involved in regulating an array of mechanisms, including oxidative stress, ferroptosis, mitochondrial and dopamine homeostasis. Loss-of-function of DJ-1 was reported to cause familial PD, and oxidative inactivation of DJ-1 has been observed in sporadic cases, suggesting that both genetic and post-translational events converge on common disease pathways. This review proposes that loss of DJ-1 function may elevate intracellular α-syn levels, leading to their aggregation and consequent neurotoxicity. Reports suggest that DJ-1 can inhibit α-syn aggregation, facilitate α-syn clearance via chaperone-mediated autophagy, and act as a deglycase or glyoxalase to neutralize glycated α-syn species. Clinical studies have also reported altered DJ-1 oxidation states in PD patient samples, supporting its potential as a biomarker. By bridging familial and sporadic PD mechanisms, DJ-1 emerges as a compelling therapeutic target with the potential to mitigate α-syn–mediated neurodegeneration across both forms. However, further research is required to fully establish its clinical relevance and translational potential. Full article

RNA-seq analysis of the highly differentiated human retinal pigment epithelial (RPE) cell-line ARPE-19, cultured on transwells for ≥4 months, yielded 44,909 genes showing 83.35% alignment with the human reference genome. These included mRNA transcripts of RPE-specific genes and those involved in retinopathies. Monolayers were fed photoreceptor outer segments (POS), designed to be synchronously internalised, mimicking homeostatic RPE activity. Cells were subsequently fixed at 4, 6, 24 and 48 h when POS were previously shown to maximally co-localise with Rab5, Rab7, LAMP/lysosomes and LC3b/autophagic compartments. A comprehensive analysis of differentially expressed genes involved in proteolysis revealed a pattern of gene orchestration consistent with POS breakdown in the autophagy-lysosomal pathway. At 4 h, these included elevated upstream signalling events promoting early stages of cargo transport and endosome maturation compared to RPE without POS exposure. This transcriptional landscape altered from 6 h, transitioning to promoting cargo degradation in autolysosomes by 24–48 h. Longitudinal scrutiny of mRNA transcripts revealed nuanced differences even within linked gene networks. POS exposure also initiated transcriptional upregulation in ubiquitin proteasome and chaperone-mediated systems within 4–6 h, providing evidence of cross-talk with other proteolytic processes. These findings show detailed evidence of transcriptome-level responses to cargo trafficking and processing in RPE cells. Full article

Targeted degradation technologies, primarily referring to targeted protein degradation, have emerged as promising drug discovery strategies. In contrast to traditional “occupancy-driven” inhibition approaches, these technologies ingeniously leverage the cell’s endogenous degradation mechanisms to achieve specific elimination of disease-causing targets. Autophagy, a highly conserved cellular clearance pathway, possesses broad substrate recognition capabilities, enabling degradation of not only individual proteins but also protein aggregates, damaged organelles, and invading pathogens. Given these characteristics, researchers are actively exploring the application of autophagy mechanisms in targeted degradation technologies. Herein, we summarize recent advances in autophagy-dependent degradation approaches, including autophagosome tethering compounds (ATTEC), autophagy-targeting chimeras (AUTAC), autophagy-targeting Chimera (AUTOTAC), chaperone-mediated autophagy (CMA)-based methods, nanotechnology-based strategies, and the newly introduced autophagy-induced antibody (AUTAB) technique, highlighting their mechanisms, advantages, and potential applications in treating tumors, neurodegenerative diseases, and other challenging conditions. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by neuronal loss, cognitive decline, and pathological hallmarks such as amyloid-beta (Aβ) plaques and tau neurofibrillary tangles. Recent evidence highlights autophagy as a pivotal mechanism in cellular homeostasis, mediating the clearance of misfolded proteins and damaged organelles. However, impaired autophagy contributes significantly to AD pathogenesis by disrupting proteostasis, exacerbating neuroinflammation, and promoting synaptic dysfunction. This review aims to scrutinize the intricate relationship between autophagy dysfunction and AD progression, explaining key pathways including macroautophagy, chaperone-mediated autophagy (CMA), and selective autophagy processes such as mitophagy and aggrephagy. This further extends the discussion beyond the central nervous system, evaluating the role of hepatic autophagy in Aβ clearance and systemic metabolic regulation. An understanding of autophagy’s involvement in AD pathology via various mechanisms could give rise to a novel therapeutic strategy targeting autophagic modulation to mitigate disease progression in the future. Full article

Malignant cells exhibit elevated rates of protein synthesis and secretion to facilitate tumor growth, proliferation, and tumorigenesis. Upon malignant transformation, the endoplasmic reticulum (ER) experiences stress due to the accumulation of unfolded or misfolded proteins in the ER lumen, lack of nutrient availability and overall hostile tumor microenvironment conditions. The demand for regulated protein turnover and proteostasis reinstatement results in the activation of the unfolded protein response (UPR) pathway for cellular adaptation and survival. The UPR machinery utilizes the BiP chaperone and three ER-bound sensors, PERK, IRE1, and ATF6, to substantiate signal transduction and orchestrate gene expression associated with protein folding, degradation and recycling, inflammation, autophagy, and programmed cell death. The pleiotropic function of UPR emerges as a central mediator for tumor progression, especially in multiple myeloma and glioblastoma pathologies. Numerous studies have recently pointed out that communication of the extracellular matrix (ECM) with surrounding tumor cells dictates in part UPR activity and vice versa. In the context of this dynamic interplay, ER stress and UPR mechanisms have been proposed as potential targets to elicit novel and effective therapeutic approaches in clinical trials. Full article

Parkinson’s disease and related synucleinopathies, including dementia with Lewy bodies and multiple system atrophy, are characterised by the pathological aggregation of the α-synuclein (aSyn) protein in neuronal and glial cells, leading to cellular dysfunction and neurodegeneration. This review synthesizes knowledge of aSyn biology, including its structure, aggregation mechanisms, cellular interactions, and systemic influences. We highlight the structural diversity of aSyn aggregates, ranging from oligomers to fibrils, their strain-like properties, and their prion-like propagation. While the role of prion-like mechanisms in disease progression remains a topic of ongoing debate, these processes may contribute to the clinical heterogeneity of synucleinopathies. Dysregulation of protein clearance pathways, including chaperone-mediated autophagy and the ubiquitin–proteasome system, exacerbates aSyn accumulation, while post-translational modifications influence its toxicity and aggregation propensity. Emerging evidence suggests that immune responses and alterations in the gut microbiome are key modulators of aSyn pathology, linking peripheral processes—particularly those of intestinal origin—to central neurodegeneration. Advances in biomarker development, such as cerebrospinal fluid assays, post-translationally modified aSyn, and real-time quaking-induced conversion technology, hold promise for early diagnosis and disease monitoring. Furthermore, positron emission tomography imaging and conformation-specific antibodies offer innovative tools for visualising and targeting aSyn pathology in vivo. Despite significant progress, challenges remain in accurately modelling human synucleinopathies, as existing animal and cellular models capture only specific aspects of the disease. This review underscores the need for more reliable aSyn biomarkers to facilitate the development of effective treatments. Achieving this goal requires an interdisciplinary approach integrating genetic, epigenetic, and environmental insights. Full article

Brain aging is driven by interconnected processes, including impaired autophagy, chronic inflammation, mitochondrial dysfunction, and cellular senescence, all of which contribute to neurovascular decline and neurodegenerative diseases such as Alzheimer’s disease (AD). Targeting these mechanisms simultaneously offers a promising therapeutic approach. This review explores the rationale for combining metformin, benzimidazole derivatives, phosphodiesterase-5 (PDE5), and acetylsalicylic acid (ASA) as a multi-targeted strategy to restore proteostasis, reduce senescence-associated secretory phenotype (SASP) factors, and enhance mitochondrial and lysosomal function. Metformin activates AMP-activated protein kinase (AMPK) and promotes autophagy initiation and chaperone-mediated autophagy, whilst benzimidazole derivatives enhance lysosomal fusion through JIP4–TRPML1 pathways independently of mTOR signaling; and ASA augments autophagic flux while suppressing NF-κB-driven inflammation and promoting specialized pro-resolving mediator pathways. This combinatorial approach targets both upstream autophagy initiation and downstream autophagosome–lysosome fusion, while concurrently attenuating inflammation and cellular senescence. Patient stratification based on the biomarkers of autophagy impairment, inflammation, and metabolic dysfunction could optimize therapeutic responses. While this strategy shows strong preclinical promise, careful attention to timing, dosing, and cell-specific responses is crucial to maximize benefits and avoid adverse effects. Future studies integrating biomarker-guided precision medicine frameworks are essential to validate the potential of this therapeutic combination in preventing or slowing cognitive decline and promoting healthy brain aging. Full article

The term autophagy identifies several mechanisms that mediate the degradation of intracellular and extracellular components via the lysosomal pathway. Three main forms of autophagy exist, namely macroautophagy, chaperone-mediated autophagy, and endosomal microautophagy, which have distinct mechanisms but share lysosomes as the final destination of their cargo. A basal autophagic flux is crucial for the maintenance of cellular homeostasis, being involved in the physiological turnover of proteins and organelles. Several stressors, including nutrient shortage and genotoxic and oxidative stress, increase the autophagic rate, which prevents the accumulation of damaged and potentially harmful cell components, thus preserving cell viability. In this context, several studies have highlighted the role of MAPKs, serine–threonine kinases activated by several stimuli, in linking oxidative stress and autophagy. Indeed, several oxidative stressors activate autophagy by converging on MAPKs, directly or indirectly. In this regard, the different transcription factors that bridge MAPKs and autophagic activation are here described. In this review, we summarize the current knowledge regarding the regulation of autophagy by MAPK, including the atypical ones, with a particular focus on the regulation of autophagy by oxidative stress. Full article

Atherosclerosis, a chronic inflammatory disease characterized by lipid accumulation and immune cell infiltration, is linked to plaque formation and cardiovascular events. While traditionally associated with lipid metabolism and endothelial dysfunction, recent research highlights the roles of autophagy and clonal hematopoiesis (CH) in its pathogenesis. Autophagy, a cellular process crucial for degrading damaged components, regulates macrophage homeostasis and inflammation, both of which are pivotal in atherosclerosis. In macrophages, autophagy influences lipid metabolism, cytokine regulation, and oxidative stress, helping to prevent plaque instability. Defective autophagy exacerbates inflammation, impairs cholesterol efflux, and accelerates disease progression. Additionally, autophagic processes in endothelial cells and smooth muscle cells further contribute to atherosclerotic pathology. Recent studies also emphasize the interplay between autophagy and CH, wherein somatic mutations in genes like TET2, JAK2, and DNMT3A drive immune cell expansion and enhance inflammatory responses in atherosclerotic plaques. These mutations modify macrophage function, intensifying the inflammatory environment and accelerating atherosclerosis. Chaperone-mediated autophagy (CMA), a selective form of autophagy, also plays a critical role in regulating macrophage inflammation by degrading pro-inflammatory cytokines and oxidized low-density lipoprotein (ox-LDL). Impaired CMA activity leads to the accumulation of these substrates, activating the NLRP3 inflammasome and worsening inflammation. Preclinical studies suggest that pharmacologically activating CMA may mitigate atherosclerosis progression. In animal models, reduced CMA activity accelerates plaque instability and increases inflammation. This review highlights the importance of autophagic regulation in macrophages, focusing on its role in inflammation, plaque formation, and the contributions of CH. Building upon current advances, we propose a hypothesis in which autophagy, programmed cell death, and clonal hematopoiesis form a critical intrinsic axis that modulates the fundamental functions of macrophages, playing a complex role in the development of atherosclerosis. Understanding these mechanisms offers potential therapeutic strategies targeting autophagy and inflammation to reduce the burden of atherosclerotic cardiovascular disease. Full article

Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by deficiency of α-galactosidase A (α-GalA), leading to the accumulation of glycosphingolipids and multi-organ dysfunction, particularly affecting the cardiovascular and renal systems. Disease-modifying treatments such as enzyme replacement therapy (ERT) and oral chaperone therapy (OCT) have limited efficacy, particularly in advanced disease, prompting a need for innovative therapeutic approaches targeting underlying molecular mechanisms beyond glycosphingolipid storage alone. Recent insights into the pathophysiology of FD highlights chronic inflammation and mitochondrial, lysosomal, and endothelial dysfunction as key mediators of disease progression. Adjunctive therapies such as sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) agonists, and mineralocorticoid receptor antagonists (MRAs) demonstrate significant cardiovascular and renal benefits in conditions including heart failure and chronic kidney disease. These drugs also modulate pathways involved in the pathophysiology of FD, such as autophagy, oxidative stress, and pro-inflammatory cytokine signaling. While theoretical foundations support their utility, dedicated trials are necessary to confirm efficacy in the FD-specific population. This narrative review highlights the importance of expanding therapeutic strategies in FD, advocating for a multi-faceted approach involving evidence-based adjunctive treatments to improve outcomes. Tailored research focusing on diverse FD phenotypes, including females and non-classical variants of disease, will be critical to advancing care and improving outcomes in this complex disorder. Full article

Lysosome-associated membrane glycoproteins (LAMPs), including lysosomal membrane protein 1 (Lamp1) and lysosomal membrane protein 2 (Lamp2), are involved in phagocytosis, chaperone-mediated autophagy (CMA), and other pathways that interact with lysosomal activity. However, the role of Lamp2 in teleosts has not been clarified. In this study, we investigated the functions of lamp2 genes during Vibrio vulnificus infection. We achieved subcellular localization of the lamp2 gene at the cellular level and performed overexpression and RNA interference experiments followed by Lipopolysaccharides (LPS) stimulation to probe the expression changes of related genes. Ultrapathology analysis of the head-kidney revealed an increase in lysosomes and the formation of autophagosomal vesicles after V. vulnificus infection, suggesting that lysosomes bind to autophagosomes. The lamp2 gene, encoding 401 amino acids in Cynoglossus semilaevis, was constitutively expressed in all examined tissues of healthy half-smooth tongue sole, with the highest expression in blood. A challenge test was conducted to assess the response of half-smooth tongue sole (Cynoglossus semilaevis) to different concentrations of V. vulnificus. The results showed that the relative expression of lamp2 and its related genes—lc3, rab7, vamp8, atg14, stx17, snap29, ctsb, and ctsd—varied with time and concentration in the gill, spleen, head-kidney, blood, liver, and gut tissues. From the results of lamp2 gene overexpression and RNA interference experiments, it is hypothesized that lamp2 positively regulates lc3, rab7, vamp8, snap29, and stx17, and negatively regulates ctsd and ctsb. Our findings provide new primary data for the function of lamp2 gene in the half-smooth tongue sole., particularly its role in regulating the immune response against V. vulnificus. Full article

The structural and functional integrity of the retinal pigment epithelium (RPE) plays a key role in the normal functioning of the visual system. RPE cells are characterized by an efficient system of photoreceptor outer segment phagocytosis, high metabolic activity, and risk of oxidative damage. RPE dysfunction is a common pathological feature in various retinal diseases. Dysregulation of RPE cell proteostasis and redox homeostasis is accompanied by increased reactive oxygen species generation during the impairment of phagocytosis, lysosomal and mitochondrial failure, and an accumulation of waste lipidic and protein aggregates. They are the inducers of RPE dysfunction and can trigger specific pathways of cell death. Autophagy serves as important mechanism in the endogenous defense system, controlling RPE homeostasis and survival under normal conditions and cellular responses under stress conditions through the degradation of intracellular components. Impairment of the autophagy process itself can result in cell death. In this review, we summarize the classical types of oxidative stress-induced autophagy in the RPE with an emphasis on autophagy mediated by molecular chaperones. Heat shock proteins, which represent hubs connecting the life supporting pathways of RPE cells, play a special role in these mechanisms. Regulation of oxidative stress-counteracting autophagy is an essential strategy for protecting the RPE against pathological damage when preventing retinal degenerative disease progression. Full article

Lipophagy is a selective degradation of lipid droplets in lysosomes or vacuoles. Apart from its role in generating energy and free fatty acids for membrane repair, growth, and the formation of new membranes, lipophagy emerges as a key player in other cellular processes and disease pathogenesis. While fungal, plant, and algal cells use microlipophagy, the most prominent form of lipophagy in animal cells is macrolipophagy. However, recent studies showed that animal cells can also use microlipophagy to metabolize their lipid droplets. Therefore, to no surprise, microlipophagy is conserved from simple unicellular to the most complex multicellular eukaryotes, and many eukaryotic cells can operate both forms of lipophagy. Macrolipophagy is the most studied and better understood at the molecular level, while our understanding of microlipophagy is very sparse. This review will discuss microlipophagy from the perspective of its conservation in eukaryotes and its importance in diseases. To better appreciate the conserved nature of microlipophagy, different organisms and types of cells in which microlipophagy has been reported are also shown in a tabular form. We also point toward the gaps in our understanding of microlipophagy, including the signaling behind microlipophagy, especially in the cells of complex multicellular organisms. Full article

Glioblastoma (GB) is one of the most aggressive and treatment-resistant cancers due to its complex tumor microenvironment (TME). We previously showed that GB progression is dependent on the aberrant induction of chaperone-mediated autophagy (CMA) in pericytes (PCs), which promotes TME immunosuppression through the PC secretome. The secretion of extracellular matrix (ECM) proteins with anti-tumor (Lumican) and pro-tumoral (Osteopontin, OPN) properties was shown to be dependent on the regulation of GB-induced CMA in PCs. As biomarkers are rarely studied in TME, in this work, we aimed to validate Lumican and OPN as prognostic markers in the perivascular areas of the peritumoral niche of a cohort of GB patients. Previously, we had validated their expression in GB xenografted mice presenting GB infiltration (OPN) or GB elimination (Lumican) dependent on competent or deficient CMA PCs, respectively. Then, patient sample classification by GB infiltration into the peritumoral brain parenchyma was related to GB-induced CMA in microvasculature PCs, analyzing the expression of the lysosomal receptor, LAMP-2A. Our results revealed a correlation between GB-induced CMA activity in peritumoral PCs and GB patients’ outcomes, identifying three degrees of severity. The perivascular expression of both immune activation markers, Iba1 and CD68, was related to CMA-dependent PC immune function and determined as useful for efficient GB prognosis. Lumican expression was identified in perivascular areas of patients with less severe outcome and partially co-localizing with PCs presenting low CMA activity, while OPN was primarily found in perivascular areas of patients with poor outcome and partially co-localizing with PCs presenting high CMA activity. Importantly, we found sex differences in the incidence of middle-aged patients, being significantly higher in men but with worse prognosis in women. Our results confirmed that Lumican and OPN in perivascular areas of the GB peritumoral niche are effective predictive biomarkers for evaluating prognosis and monitoring possible therapeutic immune responses dependent on PCs in tumor progression. Full article

Chaperone-mediated autophagy (CMA) is a selective autophagic pathway responsible for degrading cytoplasmic proteins within lysosomes. Monitoring CMA flux is essential for understanding its functions and molecular mechanisms but remains technically complex and challenging. In this study, we developed a pH-resistant probe, KFERQ-Gamillus, by screening various green fluorescent proteins. This probe is activated under conditions known to induce CMA, such as serum starvation, and relies on LAMP2A and the KFERQ motif for lysosomal localization and degradation, demonstrating its specificity for the CMA pathway. It enables the detection of CMA activity in living cells through both microscopy and image-based flow cytometry. Additionally, we created a dual-reporter system, KFERQ-Gamillus-Halo, by integrating KFERQ-Gamillus with the Halo-tag system. This probe not only distinguishes between protein synthesis and degradation but also facilitates the detection of intracellular CMA flux via immunoblotting and the rapid assessment of CMA activity using flow cytometry. Together, the KFERQ-Gamillus-Halo probe provides quantitative and time-resolved monitoring for CMA activity and flux in living cells. This tool holds promising potential for high-throughput screening and biomedical research related to CMA. Full article