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Nonsteroidal anti-inflammatory drugs repress beta-secretase gene promoter activity by the activation of PPARgamma.

Epidemiological evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the risk for Alzheimer's disease (AD). Certain NSAIDs can activate the peroxisome proliferator-activated receptor-gamma (PPARgamma), which is a nuclear transcriptional regulator. Here we show that PPARgamma depletion potentiates beta-secretase [beta-site amyloid precursor protein cleaving enzyme (BACE1)] mRNA levels by increasing BACE1 gene promoter activity. Conversely, overexpression of PPARgamma, as well as NSAIDs and PPARgamma activators, reduced BACE1 gene promoter activity. These results suggested that PPARgamma could be a repressor of BACE1. We then identified a PPARgamma responsive element (PPRE) in the BACE1 gene promoter. Mutagenesis of the PPRE abolished the binding of PPARgamma to the PPRE and increased BACE1 gene promoter activity. Furthermore, proinflammatory cytokines decreased PPARgamma gene transcription, and this effect was supressed by NSAIDs. We also demonstrate that in vivo treatment with PPARgamma agonists increased PPARgamma and reduced BACE1 mRNA and intracellular beta-amyloid levels. Interestingly, brain extracts from AD patients showed decreased PPARgamma expression and binding to PPRE in the BACE1 gene promoter. Our data strongly support a major role of PPARgamma in the modulation of amyloid-beta generation by inflammation and suggest that the protective mechanism of NSAIDs in AD involves activation of PPARgamma and decreased BACE1 gene transcription.

Aged

ADAM10's combined influence on the diagnostic usefulness of IL 22, IL 10, IL-17 A, and IL-17D in autism spectrum disorders: Predicted role on gut leakiness as co-morbidity.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing global prevalence but a lack of reliable diagnostic biomarkers. Emerging evidence suggests that immune dysregulation, gut-brain axis dysfunction, and increased intestinal permeability play key roles in ASD pathophysiology. This study investigated the combined diagnostic value of ADAM10 and cytokines (IL-10, IL-22, IL-17 A, and IL-17D). Multivariable logistic regression produces an improved ROC curve that improves diagnostic accuracy over individual markers by combining numerous predictors into a single risk score (linear predictor). The technique, which frequently raises individual marker AUCs, entails modelling a binary result, calculating the probability, and visualizing ROC based on the projected probabilities. In this case-control study, plasma levels of ADAM10, IL-10, IL-22, IL-17 A, and IL-17D were measured in 37 male children with ASD and 37 age-matched controls. Group comparisons, correlation analyses, and receiver operating characteristic (ROC) curve analyses, including combined ROC models, were performed. ADAM10, IL-22, and IL-17 A levels were significantly reduced in children with ASD compared to controls, whereas IL-10 and IL-17D showed no significant differences. ADAM10, IL-17 A, and IL-22 demonstrated good diagnostic performance, with AUC values of 0.886, 0.855, and 0.812, respectively. In contrast, IL-10 and IL-17D showed poor discriminatory ability, with AUC values of 0.524 and 0.599, respectively. Combined ROC analysis markedly improved diagnostic accuracy, with all panels including ADAM10 achieving AUC values above 0.90, and some reaching as high as 0.988, with high sensitivity and specificity. The combination of ADAM10 with selected cytokines significantly enhances diagnostic performance compared to individual markers, supporting a link between immune dysregulation, barrier dysfunction, and gut permeability in ASD.

Humans

Platelet triggering receptor expressed on myeloid cells-like transcript 1 regulation in healthy donors and patients at risk of bleeding and thrombosis.

BACKGROUND: Triggering receptor expressed on myeloid cells-like transcript 1 (TLT-1), a platelet-specific &#x3b1;-granule protein, is implicated in hemostasis, but its regulation remains unclear. Platelet dysfunction contributes to trauma-induced coagulopathy (TIC) and thrombotic complications in trauma or mechanical circulatory support (MCS); however, underlying mechanisms remain poorly understood. OBJECTIVES: This study investigated the molecular mechanisms underlying soluble TLT (sTLT)-1 release and its role as a biomarker of platelet dysfunction in patients with severe trauma or receiving MCS. METHODS: TLT-1 dynamics on platelets exposed to glycoprotein (GP)VI ligand, coagulation, or shear stress in vitro were evaluated by ELISA and immunoblotting. sTLT-1 was measured in plasma from trauma or MCS-treated patients and healthy donors. Associations with TIC, injury severity, and mortality were assessed. RESULTS: Proteolysis of TLT-1 to release a 10- to 17-kDa fragment was metalloproteinase dependent and blocked by ADAM10 and ADAM17 inhibition. Unlike GPVI, platelet TLT-1 exposure increased following PAR-1 activation. sTLT-1 was elevated in trauma patients compared with controls and correlated with TIC (P < .05) and injury severity (P < .01). Receiver-operating characteristic analysis demonstrated discriminatory performance for TIC (area under the curve, 0.78; P = .011), with a Youden cutoff of 1.180 ng/mL yielding 89% sensitivity and 73% specificity. Platelet TLT-1 was basally expressed, mobilized 2.5-fold with activation, and shed in response to GPVI ligation and plasma recalcification. Shear-exposed platelets and plasma from MCS-treated patients exhibited elevated sTLT-1 levels. CONCLUSION: Unlike GPVI, TLT-1 increased on activated platelets and was regulated by ADAM10 and ADAM17. TLT-1 release is triggered by shear stress, GPVI ligands or activated factor X. Plasma sTLT-1 was associated with trauma severity and TIC.

Humans

Poly(ADP-ribose) Polymerase 1 Deficiency Attenuates Amyloid Pathology, Neurodegeneration, and Cognitive Decline in a Familial Alzheimer's Disease Model.

Poly(ADP-ribose) (PAR) polymerase-1 (PARP1) has been implicated in DNA damage responses and neuroinflammation in Alzheimer's disease (AD), yet its role in amyloid-&#x3b2; (A&#x3b2;) pathology remains unclear. Here, we show that PARP1 activation drives A&#x3b2; pathology and neurodegeneration. Using a sensitive ELISA, we observed significantly elevated PAR levels in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment (MCI) and AD compared to controls. In vitro, oligomeric A&#x3b2;1-42 activated PARP1 and induced DNA damage, while genetic or pharmacological inhibition of PARP1 conferred neuroprotection. In vivo, PARP1 knockout in the 5XFAD mouse model of amyloidosis led to reduced amyloid plaque burden, preserved synaptic and neuronal integrity, attenuated glial activation and neuroinflammation, and rescued cognitive deficits. Mechanistically, PARP1 deficiency decreased amyloid precursor protein (APP) and BACE1 levels, altered &#x3b3;-secretase complex composition, and enhanced A&#x3b2; degradation via neprilysin. These findings position PARP1 as a critical mediator of A&#x3b2; toxicity and neurodegeneration, suggesting its inhibition as a promising therapeutic strategy for AD.

Alzheimer&#x2019;s disease