Acute peripheral versus central inhibition of insulin receptors differentially alters cytokine and blood-brain barrier responses to an inflammatory stimulus.

This cross-sectional study investigated the associations between the acute-phase proteins (APP) serum amyloid A (SAA) and haptoglobin (Hp), herd-level factors, and the seroprevalence of respiratory pathogens in Estonian dairy herds. Serum samples were analysed from 938 cows (95 herds) and 921 heifers (94 herds). Seroprevalence was tested for bovine herpesvirus 1 (BHV-1), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus 3, bovine viral diarrhoea virus, bovine coronavirus, bovine adenovirus, and Mycoplasma bovis (M. bovis). Farm visits included questionnaires on herd management practices. Linear random-intercept regression models showed higher serum SAA concentrations in cows from farms with BHV-1 seroprevalence of >50% and on BRSV-positive farms (p < 0.05), while farms employing a veterinarian had lower serum SAA concentrations. Cows had higher serum Hp concentrations in M. bovis-positive herds (p = 0.030). In heifers, serum SAA concentrations increased with low to moderate BHV-1 seroprevalence, decreased with higher M. bovis seroprevalence, and were higher in free-stall or mixed housing compared to tie-stall housing. Heifers’ serum Hp concentrations were lower in BHV-1-positive herds, but higher in herds with breeding bulls and larger herd sizes. To conclude, APP may reflect the herd health status and management-related effects on animals, supporting their use in herd-level monitoring.

ObjectivesThe aims of the present study were to evaluate the association between serum amyloid A (SAA) concentrations and proteinuria in cats without known pre-renal, renal and post-renal causes of proteinuria and to document the magnitude of proteinuria in these cases.MethodsCats with contemporaneous SAA and urine protein:creatinine ratio (UPC) data and without renal azotaemia, evidence of reduced urine concentrating ability, active urine sediment, hyperthyroidism, diabetes mellitus and recent steroid administration were included. Cats with SAA concentrations above 3.9 µg/dl were classified as having increased SAA. UPC was compared between cats with and without increased SAA using the Mann-Whitney U-test, comparisons between the proportion of cases classified as proteinuric (UPC >0.4 or >0.2) between the groups were made using Fisher's exact test, and correlations were assessed using Spearman's correlation coefficient. Multivariable logistic regression analysis was performed to examine the association between SAA and UPC.ResultsUPC was significantly higher in the increased SAA group than in the normal SAA group (0.32 [0.11-1.25] vs 0.17 [0.08-0.59]; P = 0.002) and cats with increased SAA were also more likely to be borderline or overtly proteinuric (UPC >0.2) than cats in the normal SAA group (72% vs 36%; P = 0.02). There was also a moderate positive correlation between UPC and SAA (rs = 0.519; P <0.001).Conclusions and relevanceIncreased UPC is associated with increased SAA concentrations in cats, although the severity of proteinuria in these cases is usually mild. Systemic inflammation might contribute to proteinuria in some cats, although further studies are required to establish a causal relationship.

Amyloid resistance is the reduced or abrogated ability of an organism to develop a specific type of amyloid disease. For example, it was found that certain mouse strains show resistance against systemic AA amyloidosis, due to mutations in the amyloid fibril precursor protein serum amyloid A (SAA). In this research, we find that the SAA1.5 and 2.2, two SAA-isoforms that underlie amyloid resistance in mice are unable to adopt the structure of pathogenic AA amyloid fibrils under conditions, where the pathogenic protein variant SAA1.1 does so. Furthermore, molecular dynamics simulations show that the pathogenic fibril structure does not tolerate the sequential changes present in SAA1.5 and 2.2 and becomes distorted by the variant sequences. These data imply that SAA1.5 and SAA2.2 cause amyloid resistance due to a structural incompatibility of their sequences with the specific fold of pathogenic AA amyloid fibrils.

Abstract Background The long-term triggers of recurrent inflammatory bowel disease (IBD) remain unclear. The oral microenvironment may contribute to IBD progression by regulating mucosal immunity and microbiota-host interactions. Our prior research identified salivary exosomes (SEXOs) from active-phase IBD patients (but not remission-phase or healthy controls) exacerbate intestinal inflammation, though the mechanisms are unknown. This study aims to elucidate the disease activity-dependent mechanisms by which active IBD SEXOs (IBDA-SEXOs) mediate intestinal inflammation, focusing on identifying and functionally validating key effector proteins. Methods Salivary exosomes were isolated from active-phase IBD patients, remission-phase IBD patients, and healthy controls using ultra-gradient centrifugation. Candidate proteins were screened through 4D-DIA proteomics. Epithelial-macrophage co-culture systems and T cell stimulation with macrophage-conditioned medium (Mø-CM) were employed to dissect cellular crosstalk. Mechanistic confirmation employed macrophage transfer models stimulated with SAA1 protein and exosomes derived from lentiviral-transduced SAA1overexpressing oral epithelial cells. Results Through proteomic analysis, we first identified and validated serum amyloid A1 (SAA1) as a key pro-inflammatory protein specifically enriched in salivary exosomes (IBDA-SEXOs) from patients with active inflammatory bowel disease (IBD). Functionally, SAA1 acts as a core effector molecule of IBDA-SEXOs, driving macrophage polarization toward the M1 phenotype via the TLR4–NF-κB/JNK signaling pathway, thereby exacerbating colitis in DSS-treated mice. Further investigation revealed that although IBDA-SEXOs alone do not directly induce Th17 differentiation, macrophages activated by these exosomes secrete IL-6 through the SAA1–TLR4–JNK axis. This, in cooperation with SAA1 carried by the exosomes, activates the STAT3 signaling pathway in T cells, ultimately driving pathogenic Th17 cell differentiation. Mechanistic intervention experiments demonstrated that a synthetic SAA1-inhibitory peptide (IP) effectively attenuated IBDA-SEXO-induced M1 macrophage polarization and associated pro-inflammatory effects in vivo. Finally, gain-of-function studies confirmed that exosomes derived from lentivirus-mediated SAA1-overexpressing oral epithelial cells were enriched in SAA1 and recapitulated the pro-inflammatory effects of IBDA-SEXOs in vivo—effects that were similarly blocked by the SAA1-inhibitory peptide. Conclusion SAA1functions as a key effector protein in active-phase IBD salivary exosomes, driving intestinal inflammation via oral-gut axis transmission. This finding identifies novel mechanistic and therapeutic targets for IBD. Conflict of interest: Dr. Yang, Congyi: No conflict of interest Chen, Ning: No conflict of interest

Plasma biomarkers CRP, iFABP, and zonulin as predictors of tuberculosis progression in household contacts of pulmonary TB patients.

The 104 aa protein Serum Amyloid A (SAA) is a prominent member of the acute phase response (APR) a remarkably conserved and stereotyped set of serum protein changes associated with inflammation and other stimuli. N-terminal fragments of SAA can form fibrils that accumulate in organs (where they are called "amyloidosis"). Recent reports have shown SAA involvement in inflammation, particularly with macrophages, consistent with its role as a "biomarker." In contrast to this perception of passivity, we report that exposure to both N-terminal decapeptides and intact SAA monomers can induce multiple transcripts in both enteroids and HEK293 cells. The spectrum of transcripts prominently includes proteins related to inflammation and NF-κB control, specifically NFKB1A, TNFA1P3 and IER3. SAA thus can act directly through specific transcription to alter cellular physiology in cells outside the monocyte/macrophage lineage with direct effects on inflammation, likely helping explain its remarkable evolutionary conservation as part of primordial defense.

The co-deposition of amyloid fibrils from different precursor proteins is a topic of increasing relevance for protein misfolding diseases. Using cryo-electron microscopy (cryo-EM), we here determined the structures of two serum amyloid A (SAA) protein-derived amyloid fibril morphologies that were extracted from a mouse strain that is primarily known to be associated with apolipoprotein A-II-derived amyloid fibrils. The two fibril morphologies show the same protomer conformation as in previously reported ex vivo amyloid fibrils from SAA protein but a different relative arrangement of fibril protein stacks. These data establish that serum amyloid A-derived amyloid fibrils share the same fibril protein fold in different mouse strains and disease contexts.

Natural killer (NK) cells play an important role in immune surveillance of tumors. The molecular mechanism of NK cells killing ovarian cancer cells remains elusive. This study attempts to show a potential mechanism of NK cell killing by polarization of M2 macrophages. Serum amyloid A1 protein (SAA1) expression in ovarian cancer tissue and its correlation with macrophage markers and TGF-β1 expression were analyzed using bioinformatics. TGF-β1 levels were determined by western blot and ELISA. Immunohistochemistry, flow cytometry, and immunofluorescence were employed to analyze the expression of M1 and M2 macrophage markers and NK cell markers. NK cytotoxicity was assessed using the lactate dehydrogenase assay and ELISA. TUNEL staining was used to detect tumor cell apoptosis. The xenograft tumor mouse model was utilized to reveal the invivo function of the SAA1/TGF-β1 axis. SAA1 was upregulated in ovarian cancer and positively correlated with M2 macrophage marker expression. Overexpression of SAA1 upregulated M2 macrophage markers in mouse tumor tissue. Invitro experiments showed that SAA1 induced polarization of M2 macrophages, and this effect was reversed by anti-TGF-β1 treatment. SAA1 inhibited the expression of NK cell activity markers and cytotoxicity by mediating M2 macrophage polarization. Finally, we demonstrated invivo that partial reversal of the effects of SAA1 overexpression on NK cell activity and M2 macrophage polarization was achieved through anti-TGF-β1 therapy. SAA1 repressed NK cell killing in ovarian cancer by facilitating M2 macrophage polarization through TGF-β1. The findings suggested that SAA1 may be a target for ovarian cancer therapy.

Proteomic profiling of amyloid deposits in advanced systemic light-chain (AL) amyloidosis: Insights into clonal light chains, chaperone proteins, and cardiac involvement

Dysregulation of cytoskeletal organization, energy metabolism, complement cascade, and coagulation associated with suicidal behavior: Insights from proteomic analyses.

Development of a novel targeted LC-MS/MS methods for the typing of cardiac amyloidosis.

Anxiety and depression-like symptoms are highly prevalent among methamphetamine (MA) users, particularly during the acute withdrawal (AW) phase, which plays a crucial role in the high relapse rates observed in this population. Despite their clinical importance, the mechanisms driving these withdrawal symptoms remain largely unclear. In this study, we focused on the plasma extracellular vesicles (EVs) in the MA users during the acute withdrawal (MA-AW EVs). Our findings demonstrate that the transplantation of MA-AW EVs induces anxiety and depression-like behaviors in mice, suggesting a direct link between EVs and affective withdrawal symptoms. In vivo and in vitro analyses further revealed that transplantation of MA-AW EVs induces alterations in neuronal and synaptic morphology, with withdrawal-related behaviors manifesting in a microglia-dependent manner. Proteomic profiling revealed that the EVs contained serum amyloid A-1 (SAA1) and serum amyloid A-2 (SAA2) proteins closely linked to the duration of MA withdrawal. These proteins were notably upregulated during the AW phase and declined rapidly during the protracted withdrawal (PW) stage. Subsequent experiments further validated the critical role of SAA1 in mediating anxiety and depression-like behaviors, neurotoxicity, synaptic plasticity and microgliosis. Our findings underscore the pivotal role of EVs in the MA process and suggest a close relationship between SAA1 protein and withdrawal symptoms, which may potentially serve as a novel target for MA addiction intervention.

The early and efficient diagnosis of sepsis in critically ill children remains a difficult task as the clinical signs are nonspecific. Complete blood count parameters and C‑reactive protein have low sensitivity., Also, the difficulty of its diagnosis may be due to decreased positive values of blood culture and the need for longtime to detect blood culture results. The serum Amyloid A (SAA) protein level in the blood increases earlier and up to 1000‑fold in response to inflammation. This study aimed to assess the role of SAA as diagnostic and prognostic marker in pediatric sepsis in the first 24 hours after pediatric intensive care unit (PICU) admission. This case-control study included 45 children with sepsis admitted at PICU from May 2023 to March 2024 and 45 children with matched age and sex as controls. We investigated SAA level in the same time with routine laboratory investigations of both groups. SAA level was higher in the patient group, ranged from 0.9 to 47.2 µg/m, with median 4.54 µg/ml, as compared to the control group with median 0.58 µg/ml ranged from 0 to 2.3 µg/ml. (p ≤0.001). Also, SAA level was significantly lower in the survived group with median 13.6 µg/ml, ranged from 5.7 to 20 µg/ml than the non-survived group with a median of 32.3 µg/ml; ranged from 30.3 to 47.2 µg/ml. In conclusion, we found that SAA was extremely high in critical and extremely critical ill patients which can be used as a predictor of mortality in severe sepsis among children.

Unveiling PoPFP: A short-chain pentraxin involving antibacterial immunity in marine teleost.

Does the cartilage proteome differ between osteoarthritic knees with varus and valgus deformities? Insights from proteomic analysis.

Structural Insights Into Complement Inhibition: Visualizing Distinct Binding Modes of C4b-Binding Protein Complexes With C4b and SAP

Abstract Background and objective Cardiac amyloidosis is a severe complication of periodic disease, a hereditary disorder of ancient nations in the Mediterranean basin. Early diagnosis of amyloidosis is only way to prevent an amyloidogenesis and accumulation of amyloid depositions in organs. Methods Clinical and morphological analysis of 120 patients and 107 sectional observations with diagnosis of periodic disease thoracic, abdominal and mixed forms (P±m=5,71±2,27; 22,86±4,09; 71,43±4,4) distributed in 3 groups, by age of first manifestation of disease during the life: under 5, 5-20 and above 20 years (P±m=28,57±4,4; 56,19±4,84; 15,24±3,5) respectively were done. For morphological studies Congo red, specific serum of Monoclonal Mouse Anti-Human Amyloid-A used. Results By immunocytological investigation of blood monocytes of patients, in amounts of 7,0±0,72 in the stage of chronic renal failure, 5,58±0,36 (p&amp;lt;0.05) in nephrotic, 5,55±0,42 in proteinuria, and 4,93±0,45 in latent stage, the fragments of amyloidal fibrillar protein were detected. Cardiac lesions in periodic disease in 47,6% (p&amp;lt;0,05) of cases were clinically latent, and morphological changes in sectional material in 52,4% (p&amp;lt;0,05) of cases were detected. Amyloid cardiopathy in the presence of morphologically expressed cardiomegaly with amyloid masses in the myocardium stroma in 23,8% (p&amp;lt;0,05), and in the background of amyloid cardiopathy atherosclerosis of the coronary vessels in 15,2% (p&amp;lt;0,05) of cases were detected. Amyloid angiopathies, leading to myocardial ischemia, in 3,8% (p&amp;gt;0,05) cases were observed. Conclusions Cardiac amyloidosis leads to the chronic heart failure prevailing in thanatogenesis of periodic disease. The presence of stained by immunochemical specific method of monocytes containing fragments of A-amyloid fibrillar protein, can testify the participance of these cells in the process of incomplete degradation of the serum amyloid-A protein and amyloidogenesis. The letter can use for prognosis and prevention of heart failure in periodic disease.

Objective: Secondary systemic amyloidosis occurs in patients with chronic inflammation and is a consequence of abnormal fibrillogenesis of the acute phase protein serum amyloid A. The causes of this disease development described in the literature include the possibility of inducing fibrillogenesis by introducing serum amyloid A fibrils or other proteins. This paper describes the optimization of an animal model of induced secondary amyloidosis. The prospects for using such models to search for new methods of combating amyloidosis, as well as studying the safety of new drugs based on peptides and recombinant proteins are discussed. The aim of the work was to optimize the previously described in the literature model of induced secondary systemic amyloidosis amyloidosis and to use it to assess the amyloidogenic potential of bovine serum albumin or human serum amyloid P as model proteins for development of testing methods for potential protein or peptide-based drugs. Methods: The work involved optical microscopy of animal tissue sections using the amyloid-specific dye Congo red, and the kinetics of accumulation of radioactively labeled or human serum amyloid P in the spleen were studied. Results and Discussion: A model of induced secondary systemic amyloidosis was reproduced, the presence of amyloid in the spleen of mice was confirmed microscopically and by the accumulation of radioactively labeled serum amyloid P in the spleen. Using optical microscopy, it was shown that parenteral administration of bovine serum albumin or human serum amyloid P to mice also leads to the formation of amyloid deposits in the spleen. Conclusions: In the model of secondary systemic amyloidosis used, splenic amyloidosis in mice occurs during chronic aseptic inflammation with the simultaneous administration of bovine serum albumin or human serum amyloid P. It is proposed to recommend testing potential biologically active polypeptides for their ability to induce the formation of amyloid deposits in the spleen in a murine model.

C-reactive protein (CRP) protects mice during the initial stages of Streptococcus pneumoniae infection. In order to be protective against all stages of infection, we hypothesize that CRP binds to two different ligands on pneumococci. In its native form, CRP binds to phosphocholine residues of C-polysaccharide to activate complement. In its altered form, CRP binds to amyloid-like structures (amyloids) formed on complement inhibitors recruited by pneumococci. We employed CRP knockout mice to test this hypothesis. In one approach, both wild-type CRP and E42Q/F66A/T76Y/E81A mutant CRP (E-CRP-1) were administered together. E-CRP-1 does not bind to phosphocholine but binds to amyloids. In another approach, Y40F/E42Q mutant CRP (E-CRP-2) was administered. E-CRP-2 binds to both phosphocholine and amyloids. When CRP was administered to mice 12 h after inoculation, then unlike wild-type CRP by itself, the combination of wild-type CRP and E-CRP-1 was protective and E-CRP-2 alone was protective. We also detected amyloids on pneumococci. The serum levels of the amyloid-binding protein, serum amyloid P component (SAP), were higher in CRP knockout mice than in wild-type mice. Also, the basal SAP levels were higher in female than in male mice and, conversely, male mice were more susceptible than female mice to severe infection. We conclude that the protection against prolonged pneumococcal infection requires structural changes in CRP and binding to both phosphocholine and amyloids on pneumococci. The sources of amyloids can be virulence factors or recruited complement inhibitors or both. Combined data also raise the possibility that SAP cooperates with CRP in reducing bacteremia and bacterial load.