👤 Dawn K Coletta

Physical activity (PA) and sedentary behavior (SB) are associated with many diseases, including Alzheimer's disease and all-cause dementia. However, the specific biological mechanisms through which PA protects against disease are not entirely understood. This study aims to address this gap, with a specific focus on all-cause dementia. We first assessed the conventional observational associations of three self-reported and three device-based PA/SB measures with circulating levels of 2,911 plasma proteins measured in the UK Biobank (n max =39,160) and assessed functional enrichment of identified proteins. We then used bi-directional Mendelian randomization (MR) to further evaluate the evidence for causal relationships of PA/SB with protein levels. Finally, we performed mediation analyses to identify proteins that may mediate the relationship of PA with incident all-cause dementia. Our findings revealed 41 proteins consistently associated with all PA measures and 1,027 proteins associated with at least one PA measure. Both conventional observational and MR study designs converged on proteins that appear to increase as a result of PA, including integrins such as ITGAV and ITGAM, as well as MXRA8, CLEC4A, CLEC4M, LPL, and ADGRG2; on proteins that appear to decrease as a result of PA such as LEP, INHBC, CLMP, PTGDS, ADM, OGN, and PI3; and on proteins that are more responsive to high-intensity PA, such as CA14, CA6, CA4, KIT, and ANGPT2. Functional enrichment analyses revealed processes such as cell-matrix adhesion, integrin-mediated signaling, and collagen binding. Finally, GDF15, ITGAV, ITGAM, ITGA11, HPGDS, GFAP, ADM, AHNAK, and DPP4 were among 21 unique proteins found to mediate the relationship of PA with all-cause dementia, implicating processes such as synaptic plasticity, neurogenesis, and inflammation. Our results provide insights into how PA affects biological processes and protects against dementia, and provide avenues for future research into the health-promoting effects of PA. Show less

Physical activity (PA), including sedentary behavior, is associated with many diseases, including Alzheimer's disease and all-cause dementia. However, the specific biological mechanisms through which PA protects against disease are not entirely understood. To address this knowledge gap, we first assessed the conventional observational associations of three self-reported and three device-based PA measures with circulating levels of 2,911 plasma proteins measured in the UK Biobank (n Show less

Oral squamous cell carcinoma (OSCC) remains a challenging malignancy with poor 5-year survival rates due to diagnosis at an advanced stage and a high likelihood of recurrence and metastasis. These aggressive traits may be influenced by cancer stem cells (CSC) and epithelial-mesenchymal transition (EMT). This study investigated the prognostic significance of the CSC marker CD44 and EMT-related proteins (Snail1, Snail2, E-cadherin, N-cadherin) in 132 OSCCs using immunohistochemistry. The comprehensive survival analysis included univariate and multivariate (stepwise method) Cox regression for disease-specific survival (DSS) and disease-free survival (DFS), Kaplan-Meier curves based on log-rank testing, and receiver operating characteristic (ROC) analysis to assess the predictive accuracy of the markers. High CD44 expression independently predicted worse DSS (HR = 2.74, 95% CI 1.44-5.23, p = 0.003) and DFS (HR = 2.22, 95% CI 1.16-4.23, p = 0.01), and Snail1 was significantly associated with poor DSS (HR = 2.62, 95% CI 1.37-5.03, p = 0.004). The combined expression of CD44 and Snail1 improved the discrimination of worse outcomes compared to markers individually. The presence of lymphovascular invasion (HR = 8.68, 95% CI 3.81-19.75, p < 0.0001) and a positive surgical margin (< 5 mm; HR = 4.45, 95% CI 1.99-9.96, p = 0.0003) were also independently associated with DSS. The results of this study highlight the prognostic significance of CD44 and Snail1 in OSCC, emphasizing their potential interplay in tumor aggressiveness. Show less

Associations between the WNT5A rs566926 variant and non-syndromic orofacial cleft (NSOC) have been reported in different populations. This study aimed to investigate the role of the rs566926 single nucleotide polymorphism (SNP) in WNT5A and its interactions with SNPs in BMP4, FGFR1, GREM1, MMP2, and WNT3 in the occurrence of NSOC in a Brazilian population. A case-control genetic association study was carried out involving participants from four regions of Brazil, totaling 801 patients with non-syndromic cleft lip with or without cleft palate (NSCL±P), 273 patients with cleft palate only (NSCPO), and 881 health volunteers without any congenital condition (control). Applying TaqMan allelic discrimination assays, we evaluated WNT5A rs566926 in an ancestry-structured multiple logistic regression analysis, considering sex and genomic ancestry as covariates. Interactions between rs566926 and variants in genes involved in the WNT5A signaling pathway (BMP4, FGFR1, GREM1, MMP2, and WNT3) were also explored. WNT5A rs566926 was significantly associated with an increased risk of NSCL±P, particularly due to a strong association with non-syndromic cleft lip only (NSCLO), in which the C allele increased the risk by 32% (OR: 1.32, 95% CI: 1.04-1.67, p=0.01). According to the proportions of European and African genomic ancestry, the association of rs566926 reached significant levels only in patients with European ancestry. Multiple interactions were detected between WNT5A rs566926 and BMP4 rs2071047, GREM1 rs16969681 and rs16969862, and FGFR1 rs7829058. The WNT5A rs566926 polymorphism was associated with NSCL±P, particularly in individuals with NSCLO and high European ancestry. Epistatic interactions involving WNT5A rs566926 and variants in BMP4, GREM1, and FGFR1 may contribute to the risk of NSCL±P in the Brazilian population. Show less

The study evaluated the association of Case-control study. Brazilian Oral Cleft Group. The study included 881 healthy controls and 800 patients with different types of NSOC: 232 with cleft lip only (NSCLO), 568 with cleft lip and palate (NSCLP), and 274 with cleft palate only (NSCPO). The genomic DNA was genotyped with allelic discrimination assays for five Although only nominal Our results demonstrate an increased risk of NSCL  ±  P in Brazilian individuals with enrichment of African ancestry in the presence of the Show less

To isolate cancer stem cells (CSC) from a metastatic oral squamous cell carcinoma (OSCC) cell line and investigate their in vitro and in vivo phenotypic characteristics. Subpopulations with individual staining intensities for CD44 and CD326 were isolated from the OSCC cell line LN-1A by FACS: CD44 E-cadherin levels were higher in CSC-E cells while vimentin and Slug more produced by CSC-M The CSC subpopulations here described show increased cancer capabilities in vitro, tumorigenic and metastatic potential in vivo, and may be exploited in the search for novel therapeutic targets for OSCC. Show less

The aim of the present study was to investigate the role of SNAIL1, E-cadherin, and N-cadherin immunoexpression in oral tongue carcinogenesis. In addition, we evaluated in vitro the impact of silencing of the nuclear transcription factor SNAIL1 on the viability, apoptosis, proliferation, migration, and invasion of SCC-9 and HSC-3 cells. Immunohistochemical analysis of SNAIL1, E-cadherin, and N-cadherin was carried out in 47 samples representing oral epithelial dysplasia (OED) and 41 oral tongue squamous cell carcinoma (OTSCC). The suppression of SNAIL1 expression was performed using shRNA-expression vectors in HSC-3 and SCC-9 cells to investigate in vitro the impact of SNAIL1 on proliferation, apoptosis, viability, migration, and invasion of SCC-9 and HSC-3 cells. Significant differences were observed in the expression of SNAIL1, E-cadherin, and N-Cadherin between OTSCC and OED. A low membrane expression of E-cadherin was strongly associated with poor overall survival in patients with OTSCC (P < .05), but the association did not withstand the Cox multivariate survival analysis. SNAIL1 silencing played a key role in the suppression of epithelial-mesenchymal transition and inhibited migration and invasion of HSC-3 cells (P < .0001, P < .01, respectively). In SCC-9 cells, SNAIL1 silencing promoted a significant reduction in the proliferation (P < .0001) and invasion (P < .0001). The epithelial-mesenchymal transition is present in different stages of oral tongue carcinogenesis, and SNAIL1 plays a key role in this process, although the underlying mechanisms still need to be elucidated. Thus, SNAIL1 might be a promising therapeutic target in OTSCC. Show less

Diabetic retinopathy (DR) is a microvascular complication of diabetes with a heavy impact on the quality of life of subjects and with a dramatic burden for health and economic systems on a global scale. Although the pathogenesis of DR is largely unknown, several preclinical data have pointed out to a main role of Muller glia (MG), a cell type which spans across the retina layers providing nourishment and support for Retina Ganglion Cells (RGCs), in sensing hyper-glycemia and in acquiring a pro-inflammatory polarization in response to this insult. By using a validated experimental model of DR in vitro, rMC1 cells challenged with high glucose, we uncovered the induction of an early (within minutes) and atypical Nuclear Factor-kB (NF-kB) signalling pathway regulated by a calcium-dependent calmodulin kinase II (CamKII)-proteasome axis. Phosphorylation of proteasome subunit Rpt6 (at Serine 120) by CamKII stimulated the accelerated turnover of IkBα (i.e., the natural inhibitor of p65-50 transcription factor), regardless of the phosphorylation at Serine 32 which labels canonical NF-kB signalling. This event allowed the p65-p50 heterodimer to migrate into the nucleus and to induce transcription of IL-8, Il-1β and MCP-1. Pharmacological inhibition of CamKII as well as proteasome inhibition stopped this pro-inflammatory program, whereas introduction of a Rpt6 phospho-dead mutant (Rpt6-S120A) stimulated a paradoxical effect on NF-kB probably through the activation of a compensatory mechanism which may involve phosphorylation of 20S α4 subunit. This study introduces a novel pathway of MG activation by high glucose and casts some light on the biological relevance of proteasome post-translational modifications in modulating pathways regulated through targeted proteolysis. Show less

Carfilzomib is a last generation proteasome inhibitor (PI) with proven clinical efficacy in the treatment of relapsed/refractory multiple myeloma. This drug is considered to be extremely specific in inhibiting the chymotrypsin-like activity of the 20S proteasome, encoded by the β5 subunit, overcoming some bortezomib limitations, the first PI approved for multiple myeloma therapy which is however burdened by a significant toxicity profile, due also to its off-target effects. Here, molecular approaches coupled with molecular docking studies have been used to unveil that the Insulin-Degrading Enzyme, a ubiquitous and highly conserved Zn Show less