Canine memory T-cell subsets in health and disease

Involvement of TGF-β, mTOR, and inflammatory mediators in aging alterations during myxomatous mitral valve disease in a canine model

Inflammaging, a state of chronic low-grade inflammation associated with aging, has been linked to the development and progression of various disorders. Cellular senescence, a state of irreversible growth arrest, is another characteristic of aging that contributes to the pathogenesis of cardiovascular pathology. Senescent cells accumulate in tissues over time and secrete many inflammatory mediators, further exacerbating the inflammatory environment. This senescence-associated secretory phenotype can promote tissue dysfunction and remodeling, ultimately leading to the development of age-related cardiovascular pathologies, such as mitral valve myxomatous degeneration. The species-specific form of canine myxomatous mitral valve disease (MMVD) provides a unique opportunity to investigate the early causes of induction of ECM remodeling in mitral valve leaflets in the human form of MMVD. Studies have shown that in both humans and dogs, the microenvironment of the altered leaflets is inflammatory. More recently, the focus has been on the mechanisms leading to the transformation of resting VICs (qVICs) to myofibroblast-like VICs (aVICs). Cells affected by stress fall into a state of cell cycle arrest and become senescent cells. aVICs, under the influence of TGF-β signaling pathways and the mTOR complex, enhance ECM alteration and accumulation of systemic inflammation. This review aims to create a fresh new view of the complex interaction between aging, inflammation, immunosenescence, and MMVD in a canine model, as the domestic dog is a promising model of human aging and age-related diseases.

A review of CD4+ T cell differentiation and diversity in dogs

CD4+ T cells are an integral component of the adaptive immune response, carrying out many functions to combat a diverse range of pathogenic challenges. These cells exhibit remarkable plasticity, differentiating into specialized subsets such as T helper type 1 (TH1), TH2, TH9, TH17, TH22, regulatory T cells (Tregs), and follicular T helper (TFH) cells. Each subset is capable of addressing a distinct immunological need ranging from pathogen eradication to regulation of immune homeostasis. As the immune response subsides, CD4+ T cells rest down into long-lived memory phenotypes-including central memory (TCM), effector memory (TEM), resident memory (TRM), and terminally differentiated effector memory cells (TEMRA) that are localized to facilitate a swift and potent response upon antigen re-encounter. This capacity for long-term immunological memory and rapid reactivation upon secondary exposure highlights the role CD4+ T cells play in sustaining both adaptive defense mechanisms and maintenance. Decades of mouse, human, and to a lesser extent, pig T cell research has provided the framework for understanding the role of CD4+ T cells in immune responses, but these model systems do not always mimic each other. Although our understanding of pig immunology is not as extensive as mouse or human research, we have gained valuable insight by studying this model. More akin to pigs, our understanding of CD4+ T cells in dogs is much less complete. This disparity exists in part because canine immunologists depend on paradigms from mouse and human studies to characterize CD4+ T cells in dogs, with a fraction of available lineage-defining antibody markers. Despite this, every major CD4+ T cell subset has been described to some extent in dogs. These subsets have been studied in various contexts, including in vitro stimulation, homeostatic conditions, and across a range of disease states. Canine CD4+ T cells have been categorized according to lineage-defining characteristics, trafficking patterns, and what cytokines they produce upon stimulation. This review addresses our current understanding of canine CD4+ T cells from a comparative perspective by highlighting both the similarities and differences from mouse, human, and pig CD4+ T cell biology. We also discuss knowledge gaps in our current understanding of CD4+ T cells in dogs that could provide direction for future studies in the field.

Canine Models of Inflammatory Skin Diseases and Their Application in Pharmacological Research

The purpose of this article is to provide an overview of existing pharmacological models of canine dermatitis. Canine models of dermatitis have contributed significantly to our current understanding of the pathology of dermatitis and to the development of corresponding pharmacological interventions. Specifically, canine atopic dermatitis (AD) is reviewed here, as it is one of the most common inflammatory skin diseases in dogs. Canine AD also shares clinicopathological features with human AD, making the dog a natural and optimal model for human disease. Thus, pharmacological models of canine AD may be uniquely applicable to human pharmacological research. In this article, particular attention is dedicated to relevant in vivo, in vitro, and ex vivo models of canine AD, skin barrier defect models, pruritus models, and skin immunology models. Additionally, models of superficial pyoderma and food allergy are also discussed. With understanding of findings from canine models, researchers can select the most salient features for future pharmacological drug development. © 2023 Wiley Periodicals LLC.

Plasma Extracellular Vesicle Long RNA in Diagnosis and Prediction in Small Cell Lung Cancer

(1) Introduction: The aim of this study was to identify the plasma extracellular vesicle (EV)-specific transcriptional profile in small-cell lung cancer (SCLC) and to explore the application value of plasma EV long RNA (exLR) in SCLC treatment prediction and diagnosis. (2) Methods: Plasma samples were collected from 57 SCLC treatment-naive patients, 104 non-small-cell lung cancer (NSCLC) patients and 59 healthy participants. The SCLC patients were divided into chemo-sensitive and chemo-refractory groups based on the therapeutic effects. The exLR profiles of the plasma samples were analyzed by high-throughput sequencing. Bioinformatics approaches were used to investigate the differentially expressed exLRs and their biofunctions. Finally, a t-signature was constructed using logistic regression for SCLC treatment prediction and diagnosis. (3) Results: We obtained 220 plasma exLRs profiles in all the participants. Totals of 5787 and 1207 differentially expressed exLRs were identified between SCLC/healthy controls, between the chemo-sensitive/chemo-refractory groups, respectively. Furthermore, we constructed a t-signature that comprised ten exLRs, including EPCAM, CCNE2, CDC6, KRT8, LAMB1, CALB2, STMN1, UCHL1, HOXB7 and CDCA7, for SCLC treatment prediction and diagnosis. The exLR t-score effectively distinguished the chemo-sensitive from the chemo-refractory group (p = 9.268 × 10^-9) with an area under the receiver operating characteristic curve (AUC) of 0.9091 (95% CI: 0.837 to 0.9811) and distinguished SCLC from healthy controls (AUC: 0.9643; 95% CI: 0.9256-1) and NSCLC (AUC: 0.721; 95% CI: 0.6384-0.8036). (4) Conclusions: This study firstly characterized the plasma exLR profiles of SCLC patients and verified the feasibility and value of identifying biomarkers based on exLR profiles in SCLC diagnosis and treatment prediction.