S100A4 Protein Research Articles

From Organotypic Mouse Brain Slices to Human Alzheimer’s Plasma Biomarkers: A Focus on Nerve Fiber Outgrowth

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by memory loss and progressive deterioration of cognitive functions. Being able to identify reliable biomarkers in easily available body fluids such as blood plasma is vital for the disease. To achieve this, we used a technique that applied human plasma to organotypic brain slice culture via microcontact printing. After a 2-week culture period, we performed immunolabeling for neurofilament and myelin oligodendrocyte glycoprotein (MOG) to visualize newly formed nerve fibers and oligodendrocytes. There was no significant change in the number of new nerve fibers in the AD plasma group compared to the healthy control group, while the length of the produced fibers significantly decreased. A significant increase in the number of MOG+ dots around these new fibers was detected in the patient group. According to our hypothesis, there are factors in the plasma of AD patients that affect the growth of new nerve fibers, which also affect the oligodendrocytes. Based on these findings, we selected the most promising plasma samples and conducted mass spectrometry using a differential approach and we identified three putative biomarkers: aldehyde-dehydrogenase 1A1, alpha-synuclein and protein S100-A4. Our method represents a novel and innovative approach for translating research findings from mouse models to human applications.

Characterization and Physiological Differences of Two Primary Cultures of Human Normal and Hypertrophic Scar Dermal Fibroblasts: A Pilot Study.

Background/Objectives: Dermal fibroblasts (DFs) are key participants in skin hypertrophic scarring, and their properties are being studied to identify the molecular and cellular mechanisms underlying the pathogenesis of skin scarring. Methods: In the present work, we performed a comparative analysis of DFs isolated from normal skin (normal dermal fibroblasts, NDFs), and hypertrophic scar skin (hypertrophic scar fibroblasts, HTSFs). The fibroblasts were karyotyped and phenotyped, and experiments on growth rate, wound healing, and single-cell motility were conducted. Results: Comparative analysis revealed a minor karyotype difference between cells. However, HTSFs are characterized by higher proliferation level and motility compared to NDFs. These significant differences may be associated with quantitative and qualitative differences in the cell secretome. A proteomic comparison of NDF and HTSF found that differences were associated with metabolic proteins reflecting physiological differences between the two cells lines. Numerous unique proteins were found only in the vesicular phase of vHTSFs. Some proteins involved in cell proliferation (protein-glutamine gamma-glutamyltransferase K) and cell motility (catenin delta-1), which regulate gene transcription and the activity of Rho family GTPases and downstream cytoskeletal dynamics, were identified. A number of proteins which potentially play a role in fibrosis and inflammation (mucin-5B, CD97, adhesion G protein-coupled receptor E2, antileukoproteinase, protein S100-A8 and S100-A9, protein caspase recruitment domain-containing protein 14) were detected in vHTSFs. Conclusions: A comparative analysis of primary cell cultures revealed their various properties, especially in the cell secretome. These proteins may be considered promising target molecules for developing treatment or prevention strategies for pathological skin scarring.

TMT-Based Quantitative Proteomic Profiling of Human Esophageal Cancer Cells Reveals the Potential Mechanism and Potential Therapeutic Targets Associated With Radioresistance.

The recurrence of esophageal squamous cell carcinoma (ESCC) in radiation therapy treatment presents a complex challenge due to its resistance to radiation. However, the mechanism underlying the development of radioresistance in ESCC remains unclear. In this study, we aim to uncover the mechanisms underlying radioresistance in ESCC cells and identify potential targets for radiosensitization. We established two radio-resistant cell lines, TE-1R and KYSE-150R, from the parental ESCC cell lines TE-1 and KYSE-150 through fractionated irradiation. A TMT-based quantitative proteomic profiling approach was applied to identify changes in protein expression patterns. Cell Counting Kit-8, colony formation, γH2AX foci immunofluorescence and comet assays were utilized to validate our findings. The downstream effectors of the DNA repair pathway were confirmed using an HR/NHEJ reporter assay and Western blot analysis. Furthermore, we evaluated the expression of potential targets in ESCC tissues through immunohistochemistry combined with mass spectrometry. Over 2,000 proteins were quantitatively identified in the ESCC cell lysates. A comparison with radio-sensitive cells revealed 61 up-regulated and 14 down-regulated proteins in the radio-resistant cells. Additionally, radiation treatment induced 24 up-regulated and 12 down-regulated proteins in the radio-sensitive ESCC cells. Among the differentially expressed proteins, S100 calcium binding protein A6 (S100A6), glutamine gamma-glutamyltransferase 2 (TGM2), glycogen phosphorylase, brain form (PYGB), and Thymosin Beta 10 (TMSB10) were selected for further validation studies as they were found to be over-expressed in the accumulated radio-resistant ESCC cells and radio-resistant cells. Importantly, high S100A6 expression showed a positive correlation with cancer recurrence in ESCC patients. Our results suggest that several key proteins, including S100A6, TGM2, and PYGB, play a role in the development of radioresistance in ESCC. Our results revealed that several proteins including Protein S100-A6 (S100A6), Protein-glutamine gamma-glutamyltransferase 2 (TGM2), Glycogen phosphorylase, brain form (PYGB) were involved in radio-resistance development. These proteins could potentially serve as biomarkers for ESCC radio-resistance and as therapeutic targets to treat radio-resistant ESCC cells.

S100A9 promotes renal calcium oxalate stone formation via activating the TLR4-p38/MAPK-LCN2 signaling pathway

ObjectivesTo explore the role of S100A9 protein in renal calcium oxalate (CaOx) stone formation. MethodsCaOx nephrocalcinosis mice were established via intraperitoneal injection of glyoxylate. They were treated with S100A9 deficiency, Paquinimod, or p38 MAPK-IN-1. Vonkossa staining was conducted to observe the deposition of CaOx crystals. Renal expression of inflammation, macrophage polarization, and injury markers was detected using immunohistochemistry and qPCR. Effects of S100A9 on renal tubular epithelial cells (HK−2) were explored by transcriptome sequencing. The mechanism of how S100A9 regulated lipocalin 2 (LCN2) was studied through Western Blot. Flow cytometry was performed to detect the influence of LCN2 on macrophages polarization. ResultsS100A9 deficiency inhibited the renal deposition of CaOx crystals in nephrocalcinosis mice. S100A9 upregulated the expression of LCN2 in HK-2 cells via activating the TLR4-p38/MAPK pathway. LCN2 promoted the migration and M1 polarization of macrophages. S100A9 deficiency downregulated the renal expression of LCN2, IL1-β, Kim-1, F4/80, and CD80 in nephrocalcinosis mice. Paquinimod and p38 MAPK-IN-1 both inhibited the renal deposition of CaOx crystals and downregulated the expression of LCN2, IL1-β, Kim-1, F4/80, iNOS, and CD68 in nephrocalcinosis mice. ConclusionsS100A9 promotes renal inflammatory injury by activating the TLR4-p38/MAPK-LCN2 pathway and then contributes to CaOx stone formation.

Abstract C016: Pancreatitis-induced resistance to KRAS targeted therapy: The role of cellular plasticity and underlying mechanisms

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease characterized by cell plasticity, particularly the epithelial-to-mesenchymal transition (EMT) phenotype, which significantly contributes to both pancreatic tumorigenesis and therapy resistance. Chronic pancreatitis, a key risk factor for PDAC, induces fibrosis, recruits macrophages, and elevates TGFβ, an EMT master regulator, in the tumor microenvironment (TME). Despite the observed negative correlation between dependence on oncogenic KRAS signaling and the quasi- mesenchymal (QM) subtype, the role of cellular plasticity and the underlying mechanisms of resistance remain unclear. To address this, we employed genetically engineered mouse models that mimic human pancreatitis and PDAC, alongside an in vitro 3-D tumor spheroid culture system. Our study demonstrates that chronic pancreatitis promotes resistance to KRAS- targeted therapy through a canonical TGFβ signaling pathway-dependent mechanism. Nuclear Factor of Activated T Cells 5 (NFAT5) forms a hetero-pentamer with canonical TGFβ factors SMAD3 and SMAD4, inducing EMT and promoting therapy resistance. Analysis of human samples indicates a positive correlation between NFAT5 expression and pancreatic tumorigenesis, with elevated NFAT5 expression correlating with poorer overall survival in the TCGA PDAC dataset. Functional studies reveal that genetic depletion or chemical inhibition of NFAT5 thwarts resistance to KRAS inhibition induced by TGFβ or pancreatitis, impairs the growth of QM-like escaper tumors, and synergizes with KRAS inhibitors to further suppress tumor growth in pre-clinical models. Mechanistically, we identified the chaperone protein and extracellular matrix regulator S100A4 as a key effector transcriptionally activated by the NFAT5- SMAD complex, mediating therapy resistance partially through the activation of key KRAS downstream MAPK and AKT signaling pathways. Furthermore, our investigation reveals that TGFβ stimulates PDAC cells to secrete the chemokine CCL2, which recruits circulating macrophages. In turn, these macrophages support PDAC cells in bypassing KRAS inhibition through paracrine TGFβ and S100A4. Overall, this study establishes a molecular foundation for KRAS-targeted therapy resistance associated with cellular plasticity in PDAC, highlighting pancreatitis as a potential risk factor, and proposes a novel strategy to overcome this resistance through NFAT5 inhibition or S100A4 blockade. Citation Format: Daiyong Deng, Pingping Hou. Pancreatitis-induced resistance to KRAS targeted therapy: The role of cellular plasticity and underlying mechanisms [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C016.

Netrin-1-CD146 and netrin-1-S100A9 are associated with early stage of lymph node metastasis in colorectal cancer

BackgroundThe netrin-1/CD146 pathway regulates colorectal cancer (CRC) liver metastasis, angiogenesis, and vascular development. However, few investigations have yet examined the biological function of netrin-1/CD146 complex in CRC. In this work, we investigated the relationship between the netrin-1/CD146 axis and S100 proteins in sentinel lymph node, and revealed a possible new clue for vascular metastasis of CRC.MethodsThe expression levels of netrin-1 and CD146 proteins in CRC, as well as S100A8 and S100A9 proteins in the sentinel lymph nodes were determined by immunohistochemistry. Using GEPIA and UALCAN, we analyzed netrin-1 and CD146 gene expression in CRC, their association with CRC stage, and their expression levels and prognosis in CRC patients.ResultsThe expression level of netrin-1 in N1a+1b (CRC lymphatic metastasis groups, exculded N1c) was positively increased with N0 (p = 0.012). The level of netrin-1 protein was positively correlated with CD146 protein (p < 0.05). The level of S100A9 protein was positively correlated with CD146 protein (r = 0.492, p = 0.007). Moreover, netrin-1 expression was obviously correlated with S100A9 expression in the N1 stage (r = 0.867, p = 0.000). CD146 level was correlated with S100A9 level in the N2 stage (r = 0.731, p = 0.039). CD146 mRNA expression was higher in normal colorectal tissues than in CRC (p < 0.05). Netrin-1 and CD146 expression were not significantly associated with the tumor stages and prognosis of patients with CRC (p > 0.05).ConclusionsThe netrin-1/CD146 and netrin-1/S100A9 axis in CRC tissues might related with early stage of lymph node metastasis, thus providing potential novel channels for blocking lymphatic metastasis and guiding biomarker discovery in CRC patients.

Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis.

Atomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at a molar ratio 4Ca2+:S100A9. We find that S100A9 readily assembles into a worm-like fibril, with a period dimension along the fibril axis of 11.5 nm. The fibril's chain length extends up to 136 periods after an incubation time of 144 h. At room temperature, the fibril's bending stiffness was found to be 2.95×10-28 Nm2, indicating that the fibrils are relatively flexible. Additionally, the values obtained for the Young's modulus (Ex=6.96×105 Pa and Ey=3.37×105 Pa) are four orders of magnitude lower than those typically reported for canonical amyloid fibrils. Our findings suggest that, under the investigated conditions, a distinct aggregation mechanism may be in place in the presence of calcium. Therefore, the findings reported here could have implications for the field of biomedicine, particularly with regard to Alzheimer's disease.

Mechanism of Mongolian mind-body interactive therapy in regulating essential hypertension through HTR2B: A metabolome- and transcriptome-based study

Essential hypertension is a psychosomatic disease associated with emotions and behaviors. Although Mongolian mind–body interactive therapy can help patients with essential hypertension reduce their systolic blood pressure (SBP), the mechanism is unclear. We assigned patients who underwent Mongolian mind–body interactive therapy to groups that were treated with (DT) or without (NDT) antihypertensive drugs (Clinical registration no: ChiCTR2000034918). We screened differentially expressed genes (DEGs) using targeted metabolic and transcriptomic analyses of blood samples before and after intervention. Sequenced data were analyzed using quantitative polymerase chain reaction (qPCR) and validated using enzyme-linked immunosorbent assays (ELISAs). Small interfering (Si)-RNA interference on key DEGs in human umbilical vein endothelial cells (HUVECs) was experimentally verified. Omics analysis identified 187 DEGS, including human 5-hydroxytryptamine (5-HT) receptor 2B (5-HTR2B), human endothelin receptor type B (EDNRB), and the metabolite N-acetylserotonin. The qPCR and transcriptome sequencing results were consistent. Post-intervention ELISA assays revealed significantly elevated 5-HT in the NDT group after intervention (P < 0.05). Interactions between 5-HTR2B and N-acetylserotonin differed between the groups. The cellular findings showed significantly reduced G protein-coupled receptor 82 (GPR82) and phospholipid phosphatase-related protein type 4 (PLPPR4), and significantly increased S100A2 protein expression in the Si-HTR2B group, compared with the controls (P < 0.05). The biochemical results uncovered significantly decreased nitric oxide (NO) and significantly increased malondialdehyde and NO synthetase concentrations compared with the models (P < 0.05). Mongolian mind–body interactive therapy might affect SBP in patients with essential hypertension by combining 5-HT with 5-HTR2B to mediate NO relaxation.

Repair of Mechanical Cartilage Damage Using Exosomes Derived from Deer Antler Stem Cells.

Articular cartilage has limited self-repair capacity, and current clinical treatment options for cartilage defects are inadequate. However, deer antler cartilage possesses unique regenerative properties, with the ability to rapidly repair itself. This rapid self-repair process is closely linked to the paracrine factors released by deer antler stem cells. These findings present potential for the development of cell-free therapies for cartilage defects in clinical settings. The aim of this study was to investigate a novel method for repairing cartilage. A rat model with articular cartilage defects was established through surgery. Hydrogels loaded with exosomes (Exos) derived from antler stem cells (ASC-Exos) were implanted into the rat cartilage defects. The extent of cartilage damage repair was assessed using histological methods. The effects of ASC-Exos on chondrocytes and rat bone marrow mesenchymal stem cells (BMSCs) were evaluated using cell viability assays, proliferation assays, and scratch assays. Additionally, the maintenance of the chondrocyte phenotype by ASC-Exos was assessed using real-time fluorescence quantitative PCR (qPCR) and western blot analysis. The protein components contained of the Exos were identified using data-independent acquisition (DIA) mass spectrometry. ASC-Exos significantly promoted the repair of cartilage tissue damage. The level of cartilage repair in the experimental group (ASC-Exos) was higher than that in the positive control (human adipose-derived stem cells, hADSC-Exos) and negative control (dulbecco's modified eagle medium) groups (p < 0.05). In vitro experiments demonstrated that ASC-Exos significantly enhanced the proliferation abilities of chondrocytes and the proliferation abilities and the migration abilities of BMSCs (p < 0.05). ASC-Exos up-regulated the expression levels of Aggrecan, Collagen II (COLII), and Sox9 mRNA and proteins in chondrocytes. Analysis of ASC-Exos protein components revealed the presence of active components such as Serotransferrin (TF), S100A4, and Insulin-like growth factor-binding protein 1 (IGF1). ASC-Exos have a significant effect on cartilage damage repair, which may be attributed to their promotion of chondrocyte and BMSCs proliferation and migration, as well as the maintenance of chondrocyte phenotype. This effect may be mediated by the presence of TF, S100A4, and IGF1.

Elucidating the pan-oncologic landscape of S100A9: prognostic and therapeutic corollaries from an integrative bioinformatics and Mendelian randomization analysis

The calcium-binding protein S100A9 has emerged as a pivotal biomolecular actor in oncology, implicated in numerous malignancies. This comprehensive bioinformatics study transcends traditional boundaries, investigating the prognostic and therapeutic potential of S100A9 across diverse neoplastic entities. Leveraging a wide array of bioinformatics tools and publicly available cancer genomics databases, such as TCGA, we systematically examined the S100A9 gene. Our approach included differential expression analysis, mutational burden assessment, protein interaction networks, and survival analysis. This robust computational framework provided a high-resolution view of S100A9’s role in cancer biology. The study meticulously explored S100A9’s oncogenic facets, incorporating comprehensive analyses of its relationship with prognosis, tumor mutational burden (TMB), microsatellite instability (MSI), DNA methylation, and immune cell infiltration across various tumor types. This study presents a panoramic view of S100A9 expression across a spectrum of human cancers, revealing a heterogeneous expression landscape. Elevated S100A9 expression was detected in malignancies such as BLCA (Bladder Urothelial Carcinoma), CESC (Cervical squamous cell carcinoma and endocervical adenocarcinoma), COAD (Colon adenocarcinoma), ESCA (Esophageal carcinoma), and GBM (Glioblastoma multiforme), while reduced expression was noted in BRCA (Breast invasive carcinoma), HNSC (Head and Neck squamous cell carcinoma), and KICH (Kidney Chromophobe). This disparate expression pattern suggests that S100A9’s role in cancer biology is multifaceted and context-dependent. Prognostically, S100A9 expression correlates variably with patient outcomes across different cancer types. Furthermore, its expression is intricately associated with TMB and MSI in nine cancer types. Detailed examination of six selected tumors—BRCA, CESC, KIRC (Kidney renal clear cell carcinoma), LUSC (Lung squamous cell carcinoma), SKCM (Skin Cutaneous Melanoma); STAD (Stomach adenocarcinoma)—revealed a negative correlation of S100A9 expression with the infiltration of most immune cells, but a positive correlation with neutrophils, M1 macrophages, and activated NK cells, highlighting the complex interplay between S100A9 and the tumor immune environment. This bioinformatics synthesis posits S100A9 as a significant player in cancer progression, offering valuable prognostic insights. The data underscore the utility of S100A9 as a prognostic biomarker and its potential as a therapeutic target. The therapeutic implications are profound, suggesting that modulation of S100A9 activity could significantly impact cancer management strategies.

Gut colonization with antibiotic-resistant Escherichia coli pathobionts leads to disease severity in ulcerative colitis

Escherichia coli is a Gram-negative commensal of human gut. Surprisingly, the role of E. coli in the pathogenesis of ulcerative colitis (UC) has not been explored until now. Human gut microbiota composition and meta-gut resistome were evaluated using metagenomics. Antibiotic susceptibility of E. coli isolates against different class of antibiotics was investigated. Further, the genome sequence analysis of E. coli isolates was performed to gain insight into the antimicrobial resistance (AMR) mechanism and virulence factors. Gut proteome of UC and non-UC was examined to understand the effect of resistant bacteria on host physiology. In UC patients, meta-gut resistome was found to be dominated by AMR genes (829) compared to healthy controls (HC) [518]. The metagenome study revealed a higher prevalence of AMR genes in the rural population (378 in HC; 607 in UC) compared to the urban (340 in HC; 578 in UC). Approximately, 40% of all E. coli isolates were multi-drug resistant (MDR), with higher prevalence in UC (43.75%) compared to HC (33.33%). Up-regulated expression of antimicrobial human proteins (lactotransferrin, azurocidin, cathepsin G, neutrophil elastase, and neutrophil defensin 3) and inflammatory mediator (Protein S100-A9 and Protein S100-A8) suggest microbial infection in UC gut. In addition to the conventional culturomics method, a multi-omics strategy provides deeper insights into the disease etiology, emergence of MDR pathobionts, and their roles in the disruption of the healthy gut environment in UC patients.

Core microbiome-associated proteins associated with ulcerative colitis interact with cytokines for synergistic or antagonistic effects on gut bacteria.

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is associated with a loss or an imbalance of host-microorganism interactions. However, such interactions at protein levels remain largely unknown. Here, we applied a depletion-assisted metaproteomics approach to obtain in-depth host-microbiome association networks of IBD, where the core host proteins shifted from those maintaining mucosal homeostasis in controls to those involved in inflammation, proteolysis, and intestinal barrier in IBD. Microbial nodes such as short-chain fatty-acid producer-related host-microbial crosstalk were lost or suppressed by inflammatory proteins in IBD. Guided by protein-protein association networks, we employed proteomics and lipidomics to investigate the effects of UC-related core proteins S100A8, S100A9, and cytokines (IL-1β, IL-6, and TNF-α) on gut bacteria. These proteins suppressed purine nucleotide biosynthesis in stool-derived in vitro communities, which was also reduced in IBD stool samples. Single species study revealed that S100A8, S100A9, and cytokines can synergistically or antagonistically alter gut bacteria intracellular and secreted proteome, with combined S100A8 and S100A9 potently inhibiting beneficial Bifidobacterium adolescentis. Furthermore, these inflammatory proteins only altered the extracellular but not intracellular proteins of Ruminococcus gnavus. Generally, S100A8 induced more significant bacterial proteome changes than S100A9, IL-1β, IL-6, and TNF-α but gut bacteria degrade significantly more S100A8 than S100A9 in the presence of both proteins. Among the investigated species, distinct lipid alterations were only observed in Bacteroides vulgatus treated with combined S100A8, S100A9, and cytokines. These results provided a valuable resource of inflammatory protein-centric host-microbial molecular interactions.

Exploring biomarkers for diagnosing and predicting organ dysfunction in patients with perioperative sepsis: a preliminary investigation

ObjectiveEarly diagnosis and prediction of organ dysfunction are critical for intervening and improving the outcomes of septic patients. The study aimed to find novel diagnostic and predictive biomarkers of organ dysfunction for perioperative septic patients.MethodThis is a prospective, controlled, preliminary, and single-center study of emergency surgery patients. Mass spectrometry, Gene Ontology (GO) functional analysis, and the protein-protein interaction (PPI) network were performed to identify the differentially expressed proteins (DEPs) from sepsis patients, which were selected for further verification via enzyme-linked immunosorbent assay (ELISA). Logistic regression analysis was used to estimate the relative correlation of selected serum protein levels and clinical outcomes of septic patients. Calibration curves were plotted to assess the calibration of the models.ResultsFive randomized serum samples per group were analyzed via mass spectrometry, and 146 DEPs were identified. GO functional analysis and the PPI network were performed to evaluate the molecular mechanisms of the DEPs. Six DEPs were selected for further verification via ELISA. Cathepsin B (CatB), vascular cell adhesion protein 1 (VCAM-1), neutrophil gelatinase-associated lipocalin (NGAL), protein S100-A9, prosaposin, and thrombospondin-1 levels were significantly increased in the patients with sepsis compared with those of the controls (p < 0.001). Logistic regression analysis showed that CatB, S100-A9, VCAM-1, prosaposin, and NGAL could be used for preoperative diagnosis and postoperative prediction of organ dysfunction. CatB and S100-A9 were possible predictive factors for preoperative diagnosis of renal failure in septic patients. Internal validation was assessed using the bootstrapping validation. The preoperative diagnosis of renal failure model displayed good discrimination with a C-index of 0.898 (95% confidence interval 0.843–0.954) and good calibration.ConclusionSerum CatB, S100-A9, VCAM-1, prosaposin, and NGAL may be novel markers for preoperative diagnosis and postoperative prediction of organ dysfunction. Specifically, S100-A9 and CatB were indicators of preoperative renal dysfunction in septic patients. Combining these two biomarkers may improve the accuracy of predicting preoperative septic renal dysfunction.Trial registrationThe study was registered at the Chinese Clinical Trials Registry (ChiCTR2200060418) on June 1, 2022.

Data-independent LC-MS/MS analysis of ME/CFS plasma reveals a dysregulated coagulation system, endothelial dysfunction, downregulation of complement machinery

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic condition that is characterized by unresolved fatigue, post-exertion symptom exacerbation (PESE), cognitive dysfunction, orthostatic intolerance, and other symptoms. ME/CFS lacks established clinical biomarkers and requires further elucidation of disease mechanisms. A growing number of studies demonstrate signs of hematological and cardiovascular pathology in ME/CFS cohorts, including hyperactivated platelets, endothelial dysfunction, vascular dysregulation, and anomalous clotting processes. To build on these findings, and to identify potential biomarkers that can be related to pathophysiology, we measured differences in protein expression in platelet-poor plasma (PPP) samples from 15 ME/CFS study participants and 10 controls not previously infected with SARS-CoV-2, using DIA LC-MS/MS. We identified 24 proteins that are significantly increased in the ME/CFS group compared to the controls, and 21 proteins that are significantly downregulated. Proteins related to clotting processes – thrombospondin-1 (important in platelet activation), platelet factor 4, and protein S – were differentially expressed in the ME/CFS group, suggestive of a dysregulated coagulation system and abnormal endothelial function. Complement machinery was also significantly downregulated, including C9 which forms part of the membrane attack complex. Additionally, we identified a significant upregulation of lactotransferrin, protein S100-A9, and an immunoglobulin variant. The findings from this experiment further implicate the coagulation and immune system in ME/CFS, and bring to attention the pathology of or imposed on the endothelium. This study highlights potential systems and proteins that require further research with regards to their contribution to the pathogenesis of ME/CFS, symptom manifestation, and biomarker potential, and also gives insight into the hematological and cardiovascular risk for ME/CFS individuals affected by diabetes mellitus.Graphical abstract

Pro-inflammatory protein S100A9 targeted by a natural molecule to prevent neurodegeneration onset

Accumulation of the pro-inflammatory protein S100A9 has been implicated in neuroinflammatory cascades in neurodegenerative diseases (NDs) such as Alzheimer's disease (AD) and Parkinson's disease (PD). S100A9 co-aggregates with other proteins such as α-synuclein in PD and Aβ in AD, contributing to amyloid plaque formation and neurotoxicity. The amyloidogenic nature of this protein and its role in chronic neuroinflammation suggest that it may play a key role in the pathophysiology of these diseases. Research into molecules targeting S100A9 could be a potential therapeutic strategy to prevent its amyloidogenic self-assembly and to attenuate the neuroinflammatory response in affected brain tissue. This work suggests that bioactive natural molecules, such as those found in the Mediterranean diet, may have the potential to alleviate neuroinflammation associated with the accumulation of proteins such as S100A9 in neurodegenerative diseases. A major component of extra virgin olive oil (EVOO), hydroxytyrosol (HT), with its ability to interact with and modulate S100A9 amyloid self-assembly and expression, offers a compelling approach for the development of novel and effective interventions for the prevention and treatment of ND. The findings highlight the importance of exploring natural compounds, such as HT, as potential therapeutic options for these complex and challenging neurological conditions.

S100A9 inhibits and redirects prion protein 89-230 fragment amyloid aggregation

Protein aggregation in the form of amyloid fibrils has long been associated with the onset and development of various amyloidoses, including Alzheimer's, Parkinson's or prion diseases. Recent studies of their fibril formation process have revealed that amyloidogenic protein cross-interactions may impact aggregation pathways and kinetic parameters, as well as the structure of the resulting aggregates. Despite a growing number of reports exploring this type of interaction, they only cover just a small number of possible amyloidogenic protein pairings. One such pair is between two neurodegeneration-associated proteins: the pro-inflammatory S100A9 and prion protein, which are known to co-localize in vivo. In this study, we examined their cross-interaction in vitro and discovered that the fibrillar form of S100A9 modulated the aggregation pathway of mouse prion protein 89-230 fragment, while non-aggregated S100A9 also significantly inhibited its primary nucleation process. These results complement previous observations of the pro-inflammatory protein's role in amyloid aggregation and highlight its potential role against neurodegenerative disorders.

Correlation of S100A4 and S100A14 Expression With Clinico-Pathological Features and Tumor Location in Colorectal Cancer Patients.

Background Colorectal cancer (CRC) remains a major cause of morbidity and mortality worldwide. Understanding the clinical and pathological characteristics of CRCpatients is essential for improving diagnosis, treatment, and prognostication. S100 proteins play a crucial role in CRC by promoting tumor growth, metastasis, and inflammation through their involvement in various cellular processes such as proliferation, migration, and immune response modulation. Elevated levels of specific S100 proteins have been associated with poor prognosis and serve as potential biomarkers for early detection and therapeutic targets in CRC. This study aims to analyze the general and medical characteristics of CRC patients, with a particular focus on the expression patterns of S100A4 and S100A14 proteins and their correlation with tumor location and various clinical parameters. Methods This cross-sectional study included 98 CRC patients aged 21 to 92 years. Clinical data were collected from Vajeen Hospital (Duhok/ Iraq), including age, gender, and presenting symptoms. Pathological data such as tumor site, tumor size, tumor, node, and metastasis (TNM) stage, tumor grade angio-lymphatic invasion, perineural invasion, and metastasis were analyzed. The expression of S100A4 and S100A14 proteins was assessed using immunohistochemistry, and their correlation with clinico-pathological features and tumor location was evaluated using statistical analysis. Results The 98 patients with a mean age of 57.27 years. The majority were over 50 years old (68, 69.39%) with a nearly equal gender distribution. The most common symptom was bleeding per rectum (36, 36.74%). TNM staging revealed 25.51% (n=25) of patients at stage I, 32.65% (n=32) at stage II, 24.49% (n=24) at stage III, and 17.35% (n=17) at stage IV. Angio-lymphatic invasion was present in 65.31% (n=64) of patients, and lymph node invasion in 38.78% (n=38). All tumors were adenocarcinomas, with 82.65% (n=81) being intermediate grade. S100A4 expression was low in early-stage tumors but significantly higher in advanced stages (P < 0.0001). High S100A4 expression was associated with vascular invasion (P = 0.0006), perineural invasion (P = 0.0002), lymph node invasion (P < 0.0001), and metastasis (P = 0.0010). S100A14 expression was inversely correlated with disease severity. Low S100A14 expression was more common in advanced stages (P < 0.0001) and was associated with higher rates of vascular invasion (P = 0.0018), lymph node invasion (P < 0.0001), and metastasis (P = 0.0001). Conclusion This study highlights significant correlations between S100A4 and S100A14 expression with various clinico-pathological features in CRC patients. High S100A4 expression is linked with tumor aggressiveness, whereas low S100A14 expression is associated with advanced disease stages and increased metastasis. However, there is no observed correlation between the expression of these proteins and the tumor site.

S100 proteins as potential predictive biomarkers of abatacept response in polyarticular juvenile idiopathic arthritis

BackgroundJuvenile idiopathic arthritis (JIA) comprises a heterogeneous group of conditions that can cause marked disability and diminished quality of life. Data on predictors of clinical response are insufficient to guide selection of the appropriate biologic agent for individual patients. This study aimed to investigate the propensity of S100A8/9 and S100A12 as predictive biomarkers of abatacept response in polyarticular-course juvenile idiopathic arthritis (pJIA).MethodsData from a phase 3 trial (NCT01844518) of subcutaneous abatacept in patients with active pJIA (n = 219) were used in this exploratory analysis. Association between biomarker levels at baseline and improvements in JIA-American College of Rheumatology (ACR) criteria responses or baseline disease activity (measured by Juvenile Arthritis Disease Activity Score in 27 joints using C-reactive protein [JADAS27-CRP]) were assessed. Biomarker level changes from baseline to month 4 were assessed for disease outcome prediction up to 21 months.ResultsAt baseline, 158 patients had available biomarker samples. Lower baseline S100A8/9 levels (≤ 3295 ng/mL) were associated with greater odds of achieving JIA-ACR90 (odds ratio [OR]: 2.54 [95% confidence interval (CI): 1.25–5.18]), JIA-ACR100 (OR: 3.72 [95% CI: 1.48–9.37]), JIA-ACR inactive disease (ID; OR: 4.25 [95% CI: 2.03–8.92]), JADAS27-CRP ID (OR: 2.34 [95% CI: 1.02–5.39]) at month 4, and JIA-ACR ID (OR: 3.01 [95% CI: 1.57–5.78]) at month 16. Lower baseline S100A12 levels (≤ 176 ng/mL) were associated with greater odds of achieving JIA-ACR90 (OR: 2.52 [95% CI: 1.23–5.13]), JIA-ACR100 (OR: 3.68 [95% CI: 1.46–9.28]), JIA-ACR ID (OR: 3.66 [95% CI: 1.76–7.61]), JIA-ACR90 (OR: 2.03 [95% CI: 1.07–3.87]), JIA-ACR100 (OR: 2.14 [95% CI: 1.10–4.17]), and JIA-ACR ID (OR: 4.22 [95% CI: 2.15–8.29]) at month 16. From baseline to month 4, decreases in S100A8/9 and S100A12 generally exceeded 50% among JIA-ACR90/100/ID responders.ConclusionLower baseline levels of S100A8/9 and S100A12 proteins predicted better response to abatacept treatment than higher levels and may serve as early predictive biomarkers in pJIA. Decreases in these biomarker levels may also predict longer-term response to abatacept in pJIA.

Beyond mutations: Accounting for quantitative changes in the analysis of protein evolution

Molecular phylogenetic research has relied on the analysis of the coding sequences by genes or of the amino acid sequences by the encoded proteins. Enumerating the numbers of mismatches, being indicators of mutation, has been central to pertinent algorithms. Specific amino acids possess quantifiable characteristics that enable the conversion from “words” (strings of letters denoting amino acids or bases) to “waves” (strings of quantitative values representing the physico-chemical properties) or to matrices (coordinates representing the positions in a comprehensive property space). The application of such numerical representations to evolutionary analysis takes into account not only the occurrence of mutations but also their properties as influences that drive speciation, because selective pressures favor certain mutations over others, and this predilection is represented in the characteristics of the incorporated amino acids (it is not born out solely by the mismatches). Besides being more discriminating sources for tree-generating algorithms than match/mismatch, the number strings can be examined for overall similarity with average mutual information, autocorrelation, and fractal dimension. Bivariate wavelet analysis aids in distinguishing hypermutable versus conserved domains of the protein. The matrix depiction is readily subjected to comparisons of distances, and it allows the generation of heat maps or graphs. This analysis preserves the accepted taxa order where tree construction with standard approaches yields conflicting results (for the protein S100A6). It also aids hypothesis generation about the origin of mitochondrial proteins. These analytical algorithms have been automated in R and are applicable to various processes that are describable in matrix format.

Single cell proteomics by mass spectrometry reveals deep epigenetic insight into the actions of an orphan histone deacetylase inhibitor.

Epigenetic programming has been shown to play a role in nearly every human system and disease where anyone has thought to look. However, the levels of heterogeneity at which epigenetic or epiproteomic modifications occur at single cell resolution across a population remains elusive. While recent advances in sequencing technology have allowed between 1 and 3 histone post-translational modifications to be analyzed in each single cell, over twenty separate chemical PTMs are known to exist, allowing thousands of possible combinations. Single cell proteomics by mass spectrometry (SCP) is an emerging technology in which hundreds or thousands of proteins can be directly quantified in typical human cells. As the proteins detected and quantified by SCP are heavily biased toward proteins of highest abundance, chromatin proteins are an attractive target for analysis. To this end, I applied SCP to the analysis of cancer cells treated with mocetinostat, a class specific histone deacetylase inhibitor. I find that 16 PTMs can be confidently identified and localized with high site specificity in single cells. In addition, the high abundance of histone proteins allows higher throughput methods to be utilized for SCP than ever described. While quantitative accuracy suffers when analyzing more than 700 cells per day, 9 histone proteins can be measured in single cells analyzed at even 3,500 cells per day, a throughput 10-fold greater than any previous report. In addition, the unbiased global approach utilized herein identifies a previously uncharacterized response to this drug through the S100-A8/S100-A9 protein complex partners. This response is observed in nearly every cell of the over 1,000 analyzed in this study, regardless of the relative throughput of the method utilized. While limitations exist in the methods described herein, current technologies can easily improve upon the results presented here to allow comprehensive analysis of histone PTMs to be performed in any mass spectrometry lab. All raw and processed data described in this study has been made publicly available through the ProteomeXchange/MASSIVE repository system as MSV000093434.