Search Results (161)

Background/Objectives: Postbiotics derived from lactic acid bacteria are emerging as promising antimicrobial agents due to their antibacterial, antibiofilm, and immunomodulatory properties. Among their metabolites, lactic acid (LA) is thought to play a major role in antimicrobial activity. This study investigated the proteomic response of Pseudomonas aeruginosa and Staphylococcus aureus to Lacticaseibacillus rhamnosus cell-free supernatant (CFS) and compared it with that elicited by LA alone. Methods: Overnight bacterial cultures were exposed to sub-MIC LA or CFS (1:10 for P. aeruginosa and 1:8 for S. aureus; ~12.5–15.6 mM LA) for 6 h at 37 °C. Intracellular proteins were harvested and subsequently quantified and purified to be analysed by HPLC–MS/MS, for quantitative label-free proteomics. Results: Proteomic analysis revealed clear separation of treated samples from controls, with largely overlapping responses to CFS and LA. Hallmark acid-stress adaptations were observed, including urease-mediated pH buffering, confirming that part of the response was driven by mild organic acid. In P. aeruginosa, treatments suppressed virulence pathways (phenazines, T3SS), while shifting metabolism toward lactate utilisation and reinforcing the outer membrane (lipid A, polyamine). In S. aureus, decreased abundance of the SaeRS-regulated immune-evasion factor Sbi, together with changes in envelope, ROS and translation-related proteins, suggested a bacteriostatic-like state. S. aureus differences between CFS and LA were more pronounced; CFS uniquely increased cell-wall defences, oxidative stress (SodA, SodM) and chaperone expression (GroS, GrpE), suggesting stress beyond acidification alone. Conclusions: These findings shed light on the molecular mechanisms underlying bacterial adaptation to CFS and highlight their potential as a novel antimicrobial approach. Full article

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a major metabolic disorder and is frequently accompanied by liver steatosis. Apolipoprotein J (ApoJ) is a glucose-regulated molecular chaperone that has been implicated in hepatic lipid deposition under nutrient overload. This study aimed to investigate the role of hepatocyte-specific ApoJ deletion in hepatic metabolism under diabetic conditions. Methods: A T2DM mouse model with hepatocyte-specific ApoJ knockout (HKO) was established through a high-fat diet combined with streptozotocin injection. Hepatic metabolic profiles were analyzed using untargeted metabolomics with UHPLC–MS/MS. Differential metabolites were subjected to KEGG pathway and Sankey diagram analyses to identify biologically relevant pathways. Results: In total, 140 metabolites showed significant differential abundance in HKO mouse liver, primarily encompassing organic acids and derivatives as well as lipids and lipid-like molecules. KEGG analysis revealed that ApoJ deletion enhanced pathways related to vitamin digestion and absorption, thiamine metabolism, amino acid biosynthesis, lysine degradation, and 2-oxocarboxylic acid metabolism. In contrast, pathways associated with galactose metabolism, cysteine and methionine metabolism, purine metabolism, and the pentose phosphate pathway were suppressed. Sankey diagram analysis further demonstrated that ApoJ deletion markedly reshapes hepatic metabolic networks in T2DM. Conclusions: Given the central role of hepatic dysmetabolism in the pathogenesis of diabetes and its complications, targeting ApoJ may represent a promising therapeutic approach for restoring hepatic metabolic homeostasis and preventing diabetes-associated steatosis. Full article

Protein aggregates are central to the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. This comprehensive review explores the mechanisms of protein misfolding and aggregation, their prion-like propagation, and the critical role of oligomeric species in neurotoxicity. It further examines cellular clearance pathways, including the ubiquitin–proteasome system and autophagy, alongside the regulatory functions of molecular chaperones. The review also covers advanced diagnostic imaging and biomarker techniques, as well as emerging therapeutic strategies such as pharmacological agents, gene therapy, and immunotherapy. Controversies regarding the toxicity of aggregates and future directions, including novel degradation technologies and targeted therapeutic approaches, are discussed. By integrating current knowledge, this review aims to provide a broad yet detailed overview of the field, highlighting both established concepts and promising avenues for research and treatment. Full article

Canopy FGF signaling regulator 3 (CNPY3) is a cochaperone of the molecular chaperone GRP94. CNPY3 is critical for the post-translational maturation of toll-like receptors and for regulating inflammasome signaling. However, the role of CNPY3 in cancer development and progression is still not fully understood. In this study, we aimed to investigate the role of CNPY3 in human breast cancer progression and metastasis. We used genomic and clinical information from multiple databases to profile CNPY3 and GRP94 in human cancers. We found that CNPY3 and GRP94 were elevated in human breast cancers compared to normal tissue. Higher expression of CNPY3 correlated with cancer progression and poor clinical outcomes in breast cancers. We confirmed these findings using a human breast cancer tissue array. We silenced CNPY3 in human breast cancer cells using a CRISPR/Cas9 system. For the first time, we found that deletion of CNPY3 significantly reduced tumor growth and metastasis in vitro and in vivo. Additionally, network and enrichment analyses revealed that changes in the unfolded protein response pathway and immune-related genes were significantly dependent on alterations in CNPY3 and GRP94. This study suggests that CNPY3 is a potential biomarker and novel therapeutic target for cancers. Full article

Drought stress severely limits peanut productivity, highlighting the urgent need to understand the molecular mechanisms that underlie drought adaptation. While microRNAs (miRNAs) are known to play essential roles in plant stress responses, their functional contributions in polyploid crops like peanut remain insufficiently explored. This study provides the first integrated transcriptomic analysis of drought-responsive miRNAs in tetraploid peanut (Arachis hypogaea). We performed high-throughput sRNA sequencing on a drought-tolerant cultivar Fenhua 8 under PEG6000-simulated drought stress, identifying 10 conserved drought-responsive miRNAs. Among these, ahy-miR398 and ahy-miR408 were significantly downregulated under drought conditions. Degradome sequencing revealed that ahy-miR398 targets copper chaperones for superoxide dismutase (CCSs), potentially reducing SOD activation and amplifying oxidative stress. In contrast, ahy-miR408 targets laccase 12 (LAC12), P-type ATPase copper transporters (COPAs), and a blue copper protein-like (PCL) gene. These targets are involved in copper homeostasis and the regulation of reactive oxygen species (ROS), suggesting that ahy-miR408 plays a role in oxidative stress management. Functional validation in transgenic Arabidopsis lines overexpressing ahy-miR398 or ahy-miR408 showed significantly reduced drought tolerance, with impaired seed germination, shorter primary roots, and exacerbated growth suppression during water deprivation. Taken together, these findings highlight a novel miRNA-mediated regulatory network in peanut drought adaptation, centered on copper-associated oxidative stress management. This study provides new insights into miRNA-based regulation in polyploid crops and offers potential molecular targets for breeding climate-resilient peanut varieties, especially in arid regions where yield stability is crucial. Full article

Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease are characterized by progressive neuronal loss, driven mainly by the misfolding, aggregation, and accumulation of each disease’s specific proteins. These pathogenic aggregates, including tau, α-synuclein, TDP-43, and huntingtin, disrupt cellular proteostasis and initiate cascades of neuroinflammation, oxidative stress, mitochondrial dysfunction, and synaptic failure. While protein aggregation has been a long-recognized hallmark of these disorders, growing evidence points towards a more complex interplay of initial molecular pathways with defects in RNA processing, stress granule pathology, and cell-type-specific vulnerability. Notably, such events may manifest differentially with respect to sex and are further modulated by age-related loss of the protein quality control processes like the ubiquitin–proteasome pathway, autophagy–lysosome pathway, and molecular chaperones. This review synthesizes current insights into the structural and functional dynamics of protein aggregation and its significance for neuronal well-being. It highlights the role of post-translational modifications, prion-like transmission, and aggregation kinetics in the regulation of toxicity. The review further discusses promising therapeutic strategies centered on restoring proteostasis, including small molecules that inhibit aggregation, protein clearance pathway enhancers, immunotherapy, antioxidant therapy, and diagnostic prospects such as the identification of reliable molecular signatures in bodily fluids that can reflect pathological changes even before clinical symptoms emerge. Advancements in single-cell transcriptomics and multi-omics platforms, which are changing our understanding of disease onset and progression and opening avenues for precision medicine and personalized treatments, were also discussed. Ultimately, deciphering the molecular logic that distinguishes physiological from pathological protein assemblies and understanding how cellular systems fail to adapt under stress will be key to the development of effective, disease-modifying therapies for these debilitating disorders. Full article

Molecular chaperones, especially Heat Shock Proteins (HSPs), play complex, context-dependent roles in cancer, particularly in nervous system (NS) tumors like glioblastoma (GBM) and neuroblastoma (NB). They are often upregulated, promoting tumor growth, poor prognosis, and resistance to therapy and immune responses. This supports the potential of negative chaperonotherapy, aimed at inhibiting them. However, some studies suggest chaperones can also act as tumor suppressors in certain cancers, indicating that positive chaperonotherapy—enhancing or restoring their function—may be beneficial. For NS tumors, this latter area is still understudied. With emphasis on GBM and NB, in this review we address the potential of molecular chaperones, particularly HSPs, as therapeutic targets or agents. We discuss strategies to inhibit pro-tumorigenic chaperones as well as the underexplored potential of chaperone induction and immunomodulation. Ultimately, we examine the emerging use of pharmacological and chemical chaperones to improve treatment outcomes in these NS tumors. These strategies, whether applied alone or in combination, may offer significant benefits for GBM and NB, which are presently among the most aggressive and challenging tumors to manage. Full article

The endoplasmic reticulum (ER) maintains protein homeostasis through chaperone-mediated folding and ER-associated degradation (ERAD). Disruption of this quality control, particularly involving the ER chaperone GRP94, contributes to diseases such as hypercholesterolemia, cancer, and immune disorders, where defective GRP94-dependent folding and the trafficking of client proteins like PCSK9, integrins, and Toll-like receptors drive pathology. Here, we characterize NSC637153 (cp153), a small molecule identified in a drGFP-based ERAD dislocation screen, as a selective probe of GRP94-dependent processes. cp153 inhibits the dislocation of ERAD substrates, preferentially affecting luminal clients, increases PCSK9 secretion, and promotes LDLR degradation. Unlike ATP-competitive HSP90 inhibitors, cp153 does not induce HSP70 or destabilize AKT, suggesting that it perturbs GRP94 function by interfering with client interaction or folding. The identification of cp153 provides a useful tool to for probing GRP94’s role in protein folding, trafficking, ER quality control, and disease-relevant signaling pathways, and supports the development of client-selective GRP94-targeted therapies. Full article

The seasonal patterns of viral diseases in farm animals present significant challenges to global livestock productivity, with cold stress emerging as a potential modulator of host–pathogen interactions. This review synthesizes current knowledge on the expression dynamics of heat shock protein 70 (HSP70) in farm animals under cold-stress conditions and its potential roles as (1) a viral replication facilitator and (2) an immune response regulator. This review highlights cold-induced HSP70 overexpression in essential organs, as well as its effects on significant virus life cycles, such as porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), and bovine viral diarrhea virus (BVDV), through processes like viral protein chaperoning, replication complex stabilization, and host defense modulation. By integrating insights from thermophysiology, virology, and immunology, we suggest that HSP70 serves as a crucial link between environmental stress and viral disease seasonality. We also discuss translational opportunities targeting HSP70 pathways to break the cycle of seasonal outbreaks, while addressing key knowledge gaps requiring further investigation. This article provides a framework for understanding climate-driven disease patterns and developing seasonally adjusted intervention strategies. Full article

Protein degradation plays a fundamental role in maintaining protein homeostasis and ensures proper cellular function by regulating protein quality and quantity. Heat shock protein 100 (Hsp100), found in bacteria, plants, and fungi, is a unique chaperone family responsible for rescuing misfolded proteins from aggregated states in an ATP-dependent manner. To date, they are primarily known to mediate heat stress adaptation and enhance cellular survival under extreme conditions in higher plants and algae. Resting cyst formation in dinoflagellates is widely recognized as a response to adverse conditions, which offers an adaptive advantage to endure harsh environmental extremes that are unsuitable for vegetative cell growth and survival. In this study, based on a full-length cDNA sequence, we characterized an Hsp100 gene (SaHsp100) from the cosmopolitan bloom-forming dinoflagellate Scrippsiella acuminata, aiming to examine its life stage-specific expression patterns and preliminarily explore its potential functions. The qPCR results revealed that Hsp100 transcript levels were significantly elevated in newly formed resting cysts compared to vegetative cells and continued to increase during storage under simulated marine sediment conditions (darkness, low temperature, and anoxia). Parallel reaction monitoring (PRM)-based quantification further confirmed that Hsp100 protein levels were significantly higher in resting cysts than in vegetative cells and increased after three months of storage. These findings collectively highlighted the fundamental role of Hsp100 in the alteration of the life cycle and dormancy maintenance of S. acuminata, likely by enhancing stress adaptation and promoting cell survival through participation in proteostasis maintenance, particularly under natural sediment-like conditions that trigger severe abiotic stress. Our work deepens the current understanding of Hsp family members in dinoflagellates, paving the way for future investigations into their ecological relevance within this ecologically significant group. Full article

Osteoarthritis (OA) is a prevalent and debilitating joint disease in older adults with a complex etiology. We investigated the role of SUMOylation, a post-translational modification, in OA pathogenesis, focusing on the mitochondrial chaperone Prohibitin (PHB1) and the cartilage homeostasis transcription factor PITX1. We hypothesized that oxidative stress-induced SUMOylation promotes PHB1 nuclear accumulation, leading to PITX1 downregulation and contributing to OA development. Analysis of cartilage specimens from 27 OA patients and 4 healthy controls revealed an increased nuclear accumulation of PHB1 in OA chondrocytes, accompanied by elevated levels of SUMO-1 and SUMO-2/3. Mechanistically, nuclear PHB1 interacted indirectly with SUMO-1 through a SUMO-interacting motif (SIM), and the deletion of this SIM prevented PHB1 nuclear trapping in OA cells. Furthermore, the SUMO-conjugating enzyme E2 (UBC9) encoded by the UBE2I gene was upregulated in knee OA cartilage, and its overexpression in vitro enhanced PHB1 nuclear accumulation. Consistently, transgenic mice overexpressing the Ube2i gene exhibited increased UBC9 in their knee cartilage, resulting in Pitx1 downregulation and the emergence of an early OA-like phenotype in articular chondrocytes. Our findings uncover a novel role for UBC9-mediated SUMOylation in primary knee and hip OA. This pathway enhances PHB1 nuclear accumulation, contributing to PITX1 repression and subsequent OA development. These results underscore the importance of SUMOylation in OA pathogenesis and suggest potential molecular targets for early diagnosis and therapeutic intervention. Full article

Bacterial natural ecological niches are characterized by variations in the availability of nutrients, resulting in a complex metabolism. Their impressive ability to adapt to changeable nutrient conditions is possible through the utilization of large amounts of substrates. Recent discoveries in bacterial metabolism have suggested the importance of polyamine metabolism in bacteria, particularly in those of the order Actinomycetales, in enabling them to survive in their natural habitats. This makes such enzymes promising targets to inhibit their growth. Since the polyamine metabolisms of soil bacteria of the genus Streptomyces and the human pathogenic Mycobacteria are surprisingly similar, target-based drug development in Streptomyces and Mycobacterium spp. is an alternative approach to the classical search for antibiotics. The recent development of drugs to treat epidemic diseases like tuberculosis (TB) has gained attention due to the occurrence of multidrug-resistant strains. In addition, drug repurposing plays a crucial role in the treatment of various complex diseases, such as malaria. With that notion, the treatment of TB could also benefit from this approach. For example, molecular chaperones, proteins that help other proteins to fold properly, are found in almost all living organisms, including the causative agents of TB. Therefore, targeting these molecules could help in the treatment of TB. We aim to summarize our knowledge of the nitrogen and carbon metabolism of the two closely related actinobacterial genera, Streptomyces and Mycobacterium, and of the identification of new potential drug targets. Full article

Understanding the mechanisms of immune activation and deactivation is paramount. A host must initiate effective immunity against pathogenic infections while avoiding triggering immunity against self-antigens, which can lead to detrimental autoimmune disorders. Host immunological pathways can be categorized as Immunoglobulin (Ig)G-dominant eradicable immune reactions and IgA-dominant tolerable immune reactions. Eradicable immune reactions include Th1, Th2, Th22, and Thαβ immune responses against four different types of pathogens. Tolerable immune reactions include Th1-like, Th9, Th17, and Th3 immune responses against four different types of pathogens. Here, we try to determine the mechanisms of activation and deactivation of host immune reactions. The spleen and liver play contrasting roles in mediating immune responses: the spleen is primarily involved in immune activation, whereas the liver is responsible for immune deactivation. Similarly, the sympathetic and parasympathetic nervous systems have opposing functions in immune modulation, with the sympathetic system promoting pro-inflammatory responses and the parasympathetic system facilitating anti-inflammatory processes. Furthermore, adrenocorticotropic hormone (ACTH) and glucocorticosteroids exhibit contrasting effects on immune regulation: ACTH is involved in activating adaptive immunity while inhibiting innate immunity, whereas glucocorticosteroids activate natural IgM antibody associated with innate immunity while inhibiting adaptive immunity. Heat shock proteins, particularly molecular chaperones induced by fever, play pivotal roles in immune activation. Conversely, IgD B cells and gamma/delta T cells contribute to immune deactivation through mechanisms such as clonal anergy. Understanding these mechanisms provides insights into immunological pathways, aiding in the better management of infectious diseases and autoimmune disorders. 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

Eukaryotic transcription involves a complex interplay of protein factors that dynamically engage with chromatin at distinct stages. Among these, the histone chaperone FACT (Facilitates Chromatin Transcription) plays a unique role in nucleosome disassembly and reassembly during transcription, replication, and repair. While its functional importance is well established, the underlying structural mechanisms involved in these activities remain incompletely understood. The remarkable functional versatility of FACT in regulating genetic information processing likely stems from its distinctive structural and mechanical properties. This review focuses on the structural organization of FACT and analysis of the mechanisms involved in chromatin reorganization by this unusual histone chaperone. Full article