Chaperone-like activity of the N-terminal region of a human small heat shock protein and chaperone-functionalized nanoparticles.

Small heat shock proteins (sHsps) are molecular chaperones employed to interact with a diverse range of substrates as the first line of defense against cellular protein aggregation. The N-terminal region (NTR) is implicated in defining features of sHsps; notably in their ability to form dynamic and polydisperse oligomers, and chaperone activity. The physiological relevance of oligomerization and chemical-scale mode(s) of chaperone function remain undefined. We present novel chemical tools to investigate chaperone activity and substrate specificity of human HspB1 (B1NTR), through isolation of B1NTR and development of peptide-conjugated gold nanoparticles (AuNPs). We demonstrate that B1NTR exhibits chaperone capacity for some substrates, determined by anti-aggregation assays and size-exclusion chromatography. The importance of protein dynamics and multivalency on chaperone capacity was investigated using B1NTR-conjugated AuNPs, which exhibit concentration-dependent chaperone activity for some substrates. Our results implicate sHsp NTRs in chaperone activity, and demonstrate the therapeutic potential of sHsp-AuNPs in rescuing aberrant protein aggregation.

Demonstrating the importance of local culture and susceptibility data: antibiograms from dogs at a veterinary tertiary care center.

OBJECTIVE: To create antibiograms for commonly cultured organisms in a small animal tertiary care hospital following Clinical and Laboratory Standards Institute guidelines and to compare these local resistance patterns to published first-tier antimicrobial recommendations. SAMPLE: Urine (n = 429), respiratory (41), and skin (75) isolates cultured from dogs between January 1, 2019, and December 31, 2020, at the Tufts University Foster Hospital for Small Animals. PROCEDURES: MIC and susceptibility interpretations were recorded for multiple sites for 2 years. Sites with greater than 30 isolates for at least 1 organism were included. Urinary, respiratory, and skin antibiograms were created using Clinical and Laboratory Standards Institute breakpoints and guidelines. RESULTS: Urinary Escherichia coli had a higher susceptibility percentage for amoxicillin-clavulanate (80% [221/275]) than amoxicillin alone (64% [175/275]). Respiratory E coli were greater than 80% susceptible to only 2 antimicrobials (imipenem, amikacin). Of skin Staphylococcus pseudintermedius isolates, 40% (30/75) were methicillin-resistant and frequently also displayed resistance to non-beta lactam antimicrobials. Susceptibility to recommended first-line antimicrobials varied and was greatest for gram-negative urinary isolates and lowest for methicillin-resistant S pseudintermedius skin isolates and respiratory E coli. CLINICAL RELEVANCE: Local antibiogram creation identified frequent resistance that may preclude the use of guideline-recommended first-line therapy. High levels of resistance identified in methicillin-resistant S pseudintermedius isolates supports growing concern for methicillin-resistant staphylococci in veterinary patients. This project highlights the need for population-specific resistance profiles to be used in conjunction with national guidelines.

Occupational Risk Factors and Mental Health Among Frontline Health Care Workers in a Large US Metropolitan Area During the COVID-19 Pandemic.

Objective: To assess depression, anxiety, and burnout among health care workers using well-established validated scales and to examine associations of these mental health outcomes with personal protective equipment (PPE) and high-risk patient contact.Methods: This prospective survey was conducted between August and October 2020 among 970 essential health care workers from 2 health systems in central Texas. The survey captured basic demographic, occupational, and baseline health information including history of mental health disorders. Depression, anxiety, and burnout were assessed with the 8-item Patient Health Questionnaire, 7-item Generalized Anxiety Disorder Scale, and 23-item Burnout Assessment Tool. Questions about clinical contact with patients with suspected or known COVID-19 were also incorporated.Results: Approximately 24% of respondents had moderate or severe anxiety, 14% had moderate or severe depression, and 7% were at high risk for burnout. Statistically significant associations were found between perceived PPE adequacy and the 3 mental health outcomes, while accounting for age, gender, and education. Hours of contact with COVID-19 patients during aerosolizing procedures was positively correlated with measures of anxiety, burnout, and depression after adjustment for age, gender, and occupational role. Perception of PPE adequacy was inversely correlated with measures of depression, anxiety, and burnout among essential members of 2 health care systems, whose roles precluded working remotely during the pandemic.Conclusion: This study highlights the correlations of perceptions of PPE adequacy and contact hours with COVID-19 patients undergoing aerosolizing procedures and employee mental well-being. Future work confirming the findings can help identify ways that systems can support their employees through similarly stressful and demanding events.

Dexamethasone inhibits IL-12p40 production in lipopolysaccharide-stimulated human monocytic cells by down-regulating the activity of c-Jun N-terminal kinase, the activation protein-1, and NF-kappa B transcription factors.

IL-12 plays a critical role in the development of cell-mediated immune responses and in the pathogenesis of inflammatory and autoimmune disorders. Dexamethasone (DXM), an anti-inflammatory glucocorticoid, has been shown to inhibit IL-12p40 production in LPS-stimulated monocytic cells. In this study, we investigated the molecular mechanism by which DXM inhibits IL-12p40 production by studying the role of the mitogen-activated protein kinases (MAPKs), and the key transcription factors involved in human IL-12p40 production in LPS-stimulated monocytic cells. A role for c-Jun N-terminal kinase (JNK) MAPK in LPS-induced IL-12p40 regulation in a promonocytic THP-1/CD14 cell line was demonstrated by using specific inhibitors of JNK activation, SP600125 and a dominant-negative stress-activated protein/extracellular signal-regulated kinase kinase-1 mutant. To identify transcription factors regulating IL-12p40 gene transcription, extensive deletion analyses of the IL-12p40 promoter was performed. The results revealed the involvement of a sequence encompassing the AP-1-binding site, in addition to that of NF-kappaB. The role of AP-1 in IL-12p40 transcription was confirmed by using antisense c-fos and c-jun oligonucleotides. Studies conducted to understand the regulation of AP-1 and NF-kappaB activation by JNK MAPK revealed that both DXM and SP600125 inhibited IL-12p40 gene transcription by inhibiting the activation of AP-1 and NF-kappaB transcription factors as revealed by luciferase reporter and gel mobility shift assays. Taken together, our results suggest that DXM may inhibit IL-12p40 production in LPS-stimulated human monocytic cells by down-regulating the activation of JNK MAPK, the AP-1, and NF-kappaB transcription factors.