Search Results (98)

This review reappraises the anti-inflammatory potential of the contact activation system (CAS) in intensive care through an evolutionary lens. The authors propose that coagulation factor XII (FXII) and related components evolved in terrestrial animals as a “foreign-surface sensing–immunothrombosis” module, helping to explain the minimal bleeding phenotype of FXII deficiency and the secondary loss of F12 in marine mammals. CAS shares components with the kallikrein–kinin system (KKS): alpha-coagulation factor XIIa (α-FXIIa) drives coagulation factor XI (FXI) activation to amplify coagulation, whereas betacoagulation factor XIIa (β-FXIIa) activates the KKS to generate bradykinin, promoting vasodilation and vascular leak. Beyond proteolysis, zymogen FXII signals via urokinase-type plasminogen activator receptor (uPAR) to induce neutrophil extracellular trap formation (NETosis), thereby amplifying immunothrombosis. Clinically, the relevance spans sepsis and extracorporeal organ support: pathogens can hijack CAS/KKS to facilitate invasion, and artificial surfaces such as extracorporeal membrane oxygenation (ECMO) circuits chronically trigger contact activation. In animal models, selective inhibition of FXII/FXI prolongs circuit life and attenuates pulmonary edema and inflammation without materially increasing bleeding. The review also catalogs “non-coagulation” roles of CAS members: Activated coagulation factor XI (FXIa) modulates endothelial permeability and smooth-muscle migration, and the FXII heavy chain exhibits direct antimicrobial activity—underscoring CAS as a nexus for coagulation, inflammation, and host defense. Overall, CAS inhibitors may couple “safe anticoagulation” with “cascade-level anti-inflammation,” offering a testable translational path for organ protection in the ICU alongside infection control and informing combined, precision strategies for anticoagulation and anti-inflammatory therapy. Full article

Wool traits such as fiber diameter, fiber length, and greasy fleece yield are economically significant characteristics in sheep breeding programs. Traditional genome-wide association studies (GWAS) have identified relevant genomic regions but often fail to capture the non-linear and polygenic architecture underlying these traits. In this study, we implemented a two-stage machine learning (ML)-based GWAS framework to dissect the genetic basis of wool traits in Central Anatolian Merino sheep. Phenotypic records were collected from 228 animals, genotyped with the Illumina OvineSNP50 BeadChip. In the first stage, feature selection was conducted using LASSO, Ridge Regression, and Elastic Net, generating a consensus SNP panel per trait. In the second stage, association modeling with Random Forest and Support Vector Regression (SVR) identified the most predictive models (R² up to 0.86). Candidate gene annotation highlighted biologically relevant loci: MTHFD2L and EPGN (folate metabolism and keratinocyte proliferation) for fiber diameter; COL5A2, COL3A1, ITFG1, and ELMO1 (extracellular matrix integrity and actin remodeling) for staple length; and FAP, DPP4, PLCH1, and NPTX1 (extracellular matrix remodeling, proteolysis, and sebaceous gland function) for greasy fleece yield. These findings demonstrate the utility of ML-enhanced GWAS pipelines in identifying biologically meaningful markers and propose novel targets for genomic selection strategies to improve wool quality and yield in indigenous sheep populations. Full article

Osteoarthritis (OA) lacks disease-modifying therapies, in part because key features of the joint microenvironment remain underappreciated. One such feature is localized acidosis, characterized by sustained reductions in extracellular pH within the cartilage, meniscus, and the osteochondral interface despite near-neutral bulk synovial fluid. We synthesize current evidence on the origins, sensing, and consequences of joint acidosis in OA. Metabolic drivers include hypoxia-biased glycolysis in avascular cartilage, cytokine-driven reprogramming in the synovium, and limits in proton/lactate extrusion (e.g., monocarboxylate transporters (MCTs)), with additional contributions from fixed-charge matrix chemistry and osteoclast-mediated acidification at the osteochondral junction. Acidic niches shift proteolysis toward cathepsins, suppress anabolic control, and trigger chondrocyte stress responses (calcium overload, autophagy, senescence, apoptosis). In the nociceptive axis, protons engage ASIC3 and sensitize TRPV1, linking acidity to pain. Joint cells detect pH through two complementary sensor classes: proton-sensing GPCRs (GPR4, GPR65/TDAG8, GPR68/OGR1, GPR132/G2A), which couple to G_s, G_q/11, and G_12/13 pathways converging on MAPK, NF-κB, CREB, and RhoA/ROCK; and proton-gated ion channels (ASIC1a/3, TRPV1), which convert acidity into electrical and Ca²⁺ signals. Therapeutic implications include inhibition of acid-enabled proteases (e.g., cathepsin K), pharmacologic modulation of pH-sensing receptors (with emerging interest in GPR68 and GPR4), ASIC/TRPV1-targeted analgesia, metabolic control of lactate generation, and pH-responsive intra-articular delivery systems. We outline research priorities for pH-aware clinical phenotyping and imaging, cell-type-resolved signaling maps, and targeted interventions in ‘acidotic OA’ endotypes. Framing acidosis as an actionable component of OA pathogenesis provides a coherent basis for mechanism-anchored, locality-specific disease modification. Full article

The urokinase-type plasminogen activator receptor (uPAR) plays a pivotal role in regulating extracellular proteolysis, cell migration, immune responses, and tissue remodeling across diverse physiological and pathological contexts. This review provides detailed insights into the structure of uPAR, ligand interactions, and signaling mechanisms, emphasizing its central function in cancer progression, including tumor invasion, metastasis, angiogenesis, and modulation of the tumor microenvironment. We also summarize the involvement of uPAR as a key player in cardiovascular, infectious, and neurological diseases, where it contributes to inflammation, tissue damage, and disease progression. However, translational gaps remain, most notably inconsistent assay harmonization (especially for suPAR), uncertain context-specific cut-offs and patient-selection criteria and limited multicenter validation for uPAR-targeted imaging and therapeutics. This review addresses these gaps by synthesizing cross-disease evidence to clarify clinical use cases and outline practical selection frameworks. Furthermore, we discuss the clinical potential of uPAR as a diagnostic and prognostic biomarker in diverse disease contexts, along with recent advances in therapeutic strategies targeting uPAR. Full article

Deer antler-derived medicinal materials, including antler velvet, antlers, and deer antler base, exhibit differential therapeutic efficacy across developmental stages, though their molecular mechanisms at the proteomic level remain uncharacterized. This study employed Data-Independent Acquisition (DIA) quantitative proteomics to systematically analyze protein profiles in sika deer antler velvet, antlers, and deer antler base. Comparative analysis revealed 3154 differentially expressed proteins (DEPs, 95% upregulated) between antler velvet and antlers, which were significantly enriched in Ribosome Biogenesis (e.g., Polyadenylate-binding protein), oxidative phosphorylation, and neurodegenerative disease pathways. In the comparison of deer antler base versus antlers, 1024 DEPs (92% upregulated) were identified, primarily involved in proteolysis (e.g., ACTC protein), glycolysis, and complement and coagulation cascades. Between deer antler base and antler velvet, 2749 DEPs (87% downregulated) were enriched in Thioredoxin domains, cytoskeleton regulation, and RNA-binding functions. Subcellular localization demonstrated antler velvet proteins predominantly distributed in the cytoplasm (37.6%) and nucleus (19.6%), while deer antler base proteins showed marked enrichment in extracellular regions (19.7%) and cytoskeletal components. As the first comprehensive proteomic characterization of these materials, this study identifies ribosomal proteins and complement pathway-related proteins as key biomarkers, thus establishing a scientific foundation for precise authentication, quality control, and efficacy–mechanism interpretation of deer antler-derived medicines. It further highlights antler velvet’s neuroprotective potential and deer antler base’s immunomodulatory applications. Full article

Advanced glycation end-products (AGEs) are formed by the non-enzymatic glycation of proteins, lipids, and nucleic acids due to the consumption of high-carbohydrate diets; their production is also promoted by a sedentary lifestyle as well as cigarette smoking. Elevated levels of AGEs in the circulatory system and internal organs of the body are commonly observed in a number of cardiovascular diseases such as hypertension, diabetes, atherosclerosis, coronary artery disease, aortic aneurysm, atrial fibrillation, myocardial infarction, and heart failure, which are associated with the development of oxidative stress and myocardial inflammation. The adverse effects of AGEs on the cardiovascular system are elicited by both non-receptor mechanisms involving the cross-linking of extracellular and intracellular proteins, and by receptor-mediated mechanisms involving the binding of AGEs with advanced glycation end-product receptors (RAGEs) on the cell membrane. AGE–RAGE interactions along with the cross-linking of proteins promote the generation of oxidative stress, the production of inflammation, the occurrence of intracellular Ca²⁺-overload, and alterations in the extracellular matrix leading to the development of cardiovascular dysfunction. AGEs also bind with two other protein receptors in the circulatory system: soluble RAGEs (sRAGEs) are released upon the proteolysis of RAGEs due to the activation of matrix metalloproteinase, and endogenous secretory RAGEs (esRAGEs) are secreted as a spliced variant of endogenous RAGEs. While the AGE–RAGE signal transduction axis serves as a pathogenic mechanism, both sRAGEs and esRAGEs serve as cytoprotective interventions. The serum levels of sRAGEs are decreased in ischemic heart disease, vascular disease, and heart failure, as well as in other cardiovascular diseases, but are increased in chronic diabetes and renal disease. Several interventions which can reduce the formation of AGEs, block the AGE–RAGE axis, or increase the levels of circulating sRAGEs have been shown to exert beneficial effects in diverse cardiovascular diseases. These observations support the view that the AGE–RAGE axis not only plays a critical role in pathogenesis, but is also an excellent target for the treatment of cardiovascular disease. Full article

Targeted protein degradation (TPD) has emerged as a revolutionary strategy for modulating protein function, offering a promising alternative to traditional small-molecule inhibitors. The distinctive mechanism of action in TPD has previously allowed researchers to target undruggable proteins, broadening the scope of “druggable” properties and expanding the scope of therapeutic possibilities. As the field of TPD advances, several alternative strategies to proteolysis-targeting chimeras (PROTACs) have emerged, which do not rely on the E3 ubiquitin ligase recruitment mechanism, expending the scope of TPD. Recently, several new technologies have emerged for TPD of extracellular and membrane proteins. While encouraging progress has been made in this field, the application of these technologies remains in its early stages. In this review, we explore the therapeutic potential of current key emerging lysosome-mediated TPD approaches by summarizing key discoveries and address the challenges associated with degrading extracellular and membrane protein targets. We also outline the chemical structure, activity, and pharmaceutical properties of each degrader, as well as the development of chemical probes for perturbing autophagy pathways. Full article

The present Perspective analyzes the remarkable evolution of the Amyloid Cascade Hypothesis 2.0 (ACH2.0) theory of Alzheimer’s disease (AD) since its inception a few years ago, as reflected in the diminishing role of amyloid-beta (Aβ) in the disease. In the initial iteration of the ACH2.0, Aβ-protein-precursor (AβPP)-derived intraneuronal Aβ (iAβ), accumulated to neuronal integrated stress response (ISR)-eliciting levels, triggers AD. The neuronal ISR, in turn, activates the AβPP-independent production of its C99 fragment that is processed into iAβ, which drives the disease. The second iteration of the ACH2.0 stemmed from the realization that AD is, in fact, a disease of the sustained neuronal ISR. It introduced two categories of AD—conventional and unconventional—differing mainly in the manner of their causation. The former is caused by the neuronal ISR triggered by AβPP-derived iAβ, whereas in the latter, the neuronal ISR is elicited by stressors distinct from AβPP-derived iAβ and arising from brain trauma, viral and bacterial infections, and various types of inflammation. Moreover, conventional AD always contains an unconventional component, and in both forms, the disease is driven by iAβ generated independently of AβPP. In its third, the current, iteration, the ACH2.0 posits that proteolytic production of Aβ is suppressed in AD-affected neurons and that the disease is driven by C99 generated independently of AβPP. Suppression of Aβ production in AD seems an oxymoron: Aβ is equated with AD, and the later is inconceivable without the former in an ingrained Amyloid Cascade Hypothesis (ACH)-based notion. But suppression of Aβ production in AD-affected neurons is where the logic leads, and to follow it we only need to overcome the inertia of the preexisting assumptions. Moreover, not only is the generation of Aβ suppressed, so is the production of all components of the AβPP proteolytic pathway. This assertion is not a quantum leap (unless overcoming the inertia counts as such): the global cellular protein synthesis is severely suppressed under the neuronal ISR conditions, and there is no reason for constituents of the AβPP proteolytic pathway to be exempted, and they, apparently, are not, as indicated by the empirical data. In contrast, tau protein translation persists in AD-affected neurons under ISR conditions because the human tau mRNA contains an internal ribosomal entry site in its 5′UTR. In current mouse models, iAβ derived from AβPP expressed exogenously from human transgenes elicits the neuronal ISR and thus suppresses its own production. Its levels cannot principally reach AD pathology-causing levels regardless of the number of transgenes or the types of FAD mutations that they (or additional transgenes) carry. Since the AβPP-independent C99 production pathway is inoperative in mice, the current transgenic models have no potential for developing the full spectrum of AD pathology. What they display are only effects of the AβPP-derived iAβ-elicited neuronal ISR. The paper describes strategies to construct adequate transgenic AD models. It also details the utilization of human neuronal cells as the only adequate model system currently available for conventional and unconventional AD. The final alteration of the ACH2.0, introduced in the present Perspective, is that AβPP, which supports neuronal functionality and viability, is, after all, potentially produced in AD-affected neurons, albeit not conventionally but in an ISR-driven and -compatible process. Thus, the present narrative begins with the “omnipotent” Aβ capable of both triggering and driving the disease and ends up with this peptide largely dislodged from its pedestal and retaining its central role in triggering the disease in only one, although prevalent (conventional), category of AD (and driving it in none). Among interesting inferences of the present Perspective is the determination that “sporadic AD” is not sporadic at all (“non-familial” would be a much better designation). The term has fatalistic connotations, implying that the disease can strike at random. This is patently not the case: The conventional disease affects a distinct subpopulation, and the basis for unconventional AD is well understood. Another conclusion is that, unless prevented, the occurrence of conventional AD is inevitable given a sufficiently long lifespan. This Perspective also defines therapeutic directions not to be taken as well as auspicious ways forward. The former category includes ACH-based drugs (those interfering with the proteolytic production of Aβ and/or depleting extracellular Aβ). They are legitimate (albeit inefficient) preventive agents for conventional AD. There is, however, a proverbial snowball’s chance in hell of them being effective in symptomatic AD, lecanemab, donanemab, and any other “…mab” or “…stat” notwithstanding. They comprise Aβ-specific antibodies, inhibitors of beta- and gamma-secretase, and modulators of the latter. In the latter category, among ways to go are the following: (1) Depletion of iAβ, which, if sufficiently “deep”, opens up a tantalizing possibility of once-in-a-lifetime preventive transient treatment for conventional AD and aging-associated cognitive decline, AACD. (2) Composite therapy comprising the degradation of C99/iAβ and concurrent inhibition of the neuronal ISR. A single transient treatment could be sufficient to arrest the progression of conventional AD and prevent its recurrence for life. Multiple recurrent treatments would achieve the same outcome in unconventional AD. Alternatively, the sustained reduction/removal of unconventional neuronal ISR-eliciting stressors through the elimination of their source would convert unconventional AD into conventional one, preventable/treatable by a single transient administration of the composite C99/iAβ depletion/ISR suppression therapy. Efficient and suitable ISR inhibitors are available, and it is explicitly clear where to look for C99/iAβ-specific targeted degradation agents—activators of BACE1 and, especially, BACE2. Directly acting C99/iAβ-specific degradation agents such as proteolysis-targeting chimeras (PROTACs) and molecular-glue degraders (MGDs) are also viable options. (3) A circumscribed shift (either upstream or downstream) of the position of transcription start site (TSS) of the human AβPP gene, or, alternatively, a gene editing-mediated excision or replacement of a small, defined segment of its portion encoding 5′-untranslated region of AβPP mRNA; targeting AβPP RNA with anti-antisense oligonucleotides is another possibility. If properly executed, these RNA-based strategies would not interfere with the protein-coding potential of AβPP mRNA, and each would be capable of both preventing and stopping the AβPP-independent generation of C99 and thus of either preventing AD or arresting the progression of the disease in its conventional and unconventional forms. The paper is interspersed with “validation” sections: every conceptually significant notion is either validated by the existing data or an experimental procedure validating it is proposed. Full article

Although it has been shown that the tumor extracellular matrix (ECM) may sustain the cancer stem cell (CSC) niche, its role in the modulation of CSC properties remains poorly characterized. To elucidate this, paired tumor and adjacent normal mucosa, derived from colon cancer patients’ surgical resections, were decellularized and recellularized with two distinct colon cancer cells, HT-29 or HCT-15. Methods: The matrix impact on cancer stem cell marker expression was evaluated by flow cytometry and qRT-PCR, while transforming growth factor-β (TGF-β) secretion and matrix metalloprotease (MMP) activity were quantified by ELISA and zymography. Results: In contrast to their paired normal counterparts, the tumor decellularized matrices enhanced HT-29 expression of the pluripotency and stemness genes NANOG (p = 0.0117), SOX2 (p = 0.0156), and OCT4 (p = 0.0312) and of the epithelial-to-mesenchymal transition (EMT)-associated transcription factor SNAI1 (p = 0.0156). Notably, no significant differences were found in the expression of SLUG or TGFB on HT-29 or of the six transcripts on HCT-15 cells. HT-29 mRNA alterations were followed by enhanced expression of the stemness-associated receptors cluster of differentiation 44 (CD44), CD133, and CD166 (p = 0.0078), the secretion of TGF-β (p = 0.0286), and MMP-2 (p = 0.0081) and MMP-9 (p = 0.0402) proteolysis. To infer the clinical relevance of these findings, we assessed cohort databases and evidenced that patients expressing higher levels of the four stemness-associated genes (NANOG/SOX2/OCT4/SNAI1) had worse overall survival. This study demonstrates that normal and tumor matrices harbor different stemness potential and suggest patient-derived decellularized matrices as an excellent three-dimensional (3D) model to unveil stemness signatures, appointing candidates for future therapeutic strategies. Full article

Amyotrophic lateral sclerosis (ALS) is a devastating neuromuscular disease characterized by progressive motor neuron degeneration and muscle atrophy, with no effective treatments available. Chronic inflammation, which impairs muscle regeneration and promotes proteolysis, is a key contributor to ALS-related muscle atrophy and a promising therapeutic target. Here, we applied extracellular vesicles (EVs) derived from regenerating skeletal muscles 14 days post-acute injury (CTXD14SkM-EVs), which possess a unique anti-inflammatory profile, to target muscle defects in ALS. We found that CTXD14SkM-EVs enhanced myoblast differentiation and fusion in a cellular muscle-wasting model induced by pro-inflammatory cytokine tumor necrosis factor alpha. Intramuscular administration of these EVs into an ALS mouse model mitigated muscle atrophy by promoting muscle regeneration, shifting macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 state, and suppressing the aberrant Nuclear Factor Kappa B (NF-κB) signaling, a key driver of muscle protein degradation. These results underscore the therapeutic potential of regenerating muscle-derived EVs for combating muscle atrophy in ALS. Full article

Mitochondria are the powerhouses of cells, also involved in ROS (reactive oxygen species) generation and cellular death regulation. Thus, several diseases are associated with mitochondrial impairment, including cardiovascular disorders (CVDs). Since CVDs are currently the leading cause of death worldwide, it is very important to evaluate targeting mitochondrial effectors in clinical treatment protocols. Hence, in the present study, antimycin A and rotenone, established inhibitors of the mitochondrial electron transfer chain, were shown to halt apoptotic death induced by curcumin (50 μM) and sorbitol (0.5 M), in H9c2 cardiac cells. In particular, immunoblotting analysis revealed that they totally abolished PARP [poly(ADP-ribose) polymerase] proteolysis, under these conditions. This finding was accompanied by an enhancement of cell viability, recovery of mitochondria networks’ integrity, suppression of cytochrome c release into the cytoplasm, and reversal of chromatin condensation. Chelating extracellular calcium (with EGTA) further enhanced the beneficial impact of antimycin A and rotenone on curcumin- or sorbitol-treated H9c2 cells viability. Of interest, the phosphorylation of eIF2α, indicative of the onset of the pro-survival Integrated Stress Response (IRS), was sustained under these conditions. Overall, our data highlight the anti-apoptotic effect of these compounds, unmasking their potential as mediators in novel therapeutic interventions against mitochondria-associated cardiac dysfunction. Full article

The Aedes aegypti mosquito is responsible for transmitting pathogens such as the Dengue, Zika, and Chikungunya viruses. The peritrophic matrix (PM) is an extracellular chitin-rich structure that lines the midgut of arthropods, providing a crucial protective barrier for the gut epithelium against mechanical damage, ingested pathogens, and toxic substances. During blood digestion, hemoglobin is lysed, releasing free heme into the midgut lumen. Part of this heme binds strongly to the PM, mitigating its harmful effects on the mosquito epithelial cells. Our study focused on investigating the interaction dynamic between hemoglobin and the PM during blood digestion in A. aegypti. Optical microscopy was employed to observe the temporal progression of blood digestion in the A. aegypti midgut, highlighting significant morphological changes in the blood bolus. An electrophoresis analysis revealed distinct protein bands in the PM extract, some of which were associated with hemoglobin and its subunits. The presence of PM-associated hemoglobin was confirmed by amino-terminal sequencing and an immunoblot analysis using anti-hemoglobin antibodies. Furthermore, fluorescence microscopy revealed overlapping labeling between hemoglobin and chitin, suggesting an interaction between hemoglobin and PM chitin. Corroborating these results, hemoglobin showed an affinity with chitin in the chromatography and molecular docking assays, in which the hemoglobin subunits interacted with the oligosaccharide (NAG)₄. Thus, hemoglobin may perform a function similar to that of peritrophins. Further experiments demonstrated the protective role of the PM against hemoglobin proteolysis during blood digestion. Overall, this study provides valuable insights into the intricate interactions between hemoglobin and the PM, enhancing our understanding of mosquito digestive physiology and potentially contributing to the development of vector control strategies. Full article

Enzyme-mediated protein degradation is a major concern in industrial fungal strain improvement, making low-proteolytic strains preferable for enhanced protein production. Here, we improved food-grade Aspergillus oryzae BCC7051 by manipulating the transcriptional regulation of protease-encoding genes. Genome mining of the transcription factor AoprtR and computational analysis confirmed its deduced amino acid sequence sharing evolutionary conservation across Aspergillus and Penicillium spp. The AoPrtR protein, which is classified into the Zn(II)2-Cys6-type transcription factor family, manipulates both intra- and extracellular proteolytic enzymes. Our transcriptional analysis indicated that the regulation of several protease-encoding genes was AoPrtR-dependent, with AoPrtR acting as a potent activator for extracellular acid-protease-encoding genes and a likely repressor for intracellular non-acid-protease-encoding genes. An indirect regulatory mechanism independent of PrtR may enhance proteolysis. Moreover, AoPrtR disruption increased extracellular esterase production by 2.55-fold, emphasizing its role in protein secretion. Our findings highlight the complexity of AoPrtR-mediated regulation by A. oryzae. Manipulation of regulatory processes through AoPrtR prevents secreted protein degradation and enhances the quantity of extracellular proteins, suggesting the low-proteolytic variant as a promising platform for the production of these proteins. This modified strain has biotechnological potential for further refinement and sustainable production of bio-based products in the food, feed, and nutraceutical industries. Full article

Background: The present study investigates VKINE, a bioactive proteolytic fragment of the proteoglycan VCAN, as a novel and significant element in the tumor extracellular matrix (ECM). Although VKINE has been recognized for its immunomodulatory potential in certain tumor types, its impact on ECM degradation and prognostic implications remains poorly understood. Objectives: This study aimed to evaluate VCAN proteolysis and its association with ADAMTS enzymes involved in extracellular matrix remodeling in spontaneous canine mammary gland cancer. Methods: The expression levels of VKINE, ADAMTS enzymes, and collagen fibers were comparatively analyzed in situ and in invasive areas of carcinoma in mixed tumor (CMT) and carcinosarcoma (CSS) with different prognoses. Results: VKINE was notably expressed in the stroma adjacent to the invasion areas in CMT, whereas ADAMTS-15 was identified as the enzyme associated with VCAN proteolysis. Inverse correlations were observed between type III collagen and VCAN expression in in situ areas. Conclusions: Our findings suggest that VKINE and ADAMTS-15 play crucial roles in the tumor microenvironment, influencing invasiveness and type III collagen deposition. This study contributes to a better understanding of the dynamics within the ECM, paving the way for potential new tools in diagnosing and treating human and canine mammary tumors. Full article