Cells

18 pages, 761 KiB

Open AccessReview

Immunomodulatory Functions of TNF-Related Apoptosis-Inducing Ligand in Type 1 Diabetes

by Marton Fogarasi and Simona Dima

Cells 2024, 13(20), 1676; https://doi.org/10.3390/cells13201676 (registering DOI) - 10 Oct 2024

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF protein superfamily and was initially identified as a protein capable of inducing apoptosis in cancer cells. In addition, TRAIL can promote pro-survival and proliferation signaling in various cell types. Subsequent studies have demonstrated that TRAIL plays several important roles in immunoregulation, immunosuppression, and immune effector functions. Type 1 diabetes (T1D) is an autoimmune disease characterized by hyperglycemia due to the loss of insulin-producing β-cells, primarily driven by T-cell-mediated pancreatic islet inflammation. Various genetic, epigenetic, and environmental factors, in conjunction with the immune system, contribute to the initiation, development, and progression of T1D. Recent reports have highlighted TRAIL as an important immunomodulatory molecule with protective effects on pancreatic islets. Experimental data suggest that TRAIL protects against T1D by reducing the proliferation of diabetogenic T cells and pancreatic islet inflammation and restoring normoglycemia in animal models. In this review, we aimed to summarize the consequences of TRAIL action in T1D, focusing on and discussing its signaling mechanisms, role in the immune system, and protective effects in T1D. Full article

18 pages, 1096 KiB

Open AccessReview

Autophagy-Mediated Cellular Remodeling during Terminal Differentiation of Keratinocytes in the Epidermis and Skin Appendages

by Leopold Eckhart, Florian Gruber and Supawadee Sukseree

Cells 2024, 13(20), 1675; https://doi.org/10.3390/cells13201675 (registering DOI) - 10 Oct 2024

Abstract

The epidermis of the skin and skin appendages, such as nails, hair and sebaceous glands, depend on a balance of cell proliferation and terminal differentiation in order to fulfill their functions at the interface of the body and the environment. The differentiation of epithelial cells of the skin, commonly referred to as keratinocytes, involves major remodeling processes that generate metabolically inactive cell remnants serving as building blocks of the epidermal stratum corneum, nail plates and hair shafts. Only sebaceous gland differentiation results in cell disintegration and holocrine secretion. A series of studies performed in the past decade have revealed that the lysosome-dependent intracellular degradation mechanism of autophagy is active during keratinocyte differentiation, and the blockade of autophagy significantly alters the properties of the differentiation products. Here, we present a model for the autophagy-mediated degradation of organelles and cytosolic proteins as an important contributor to cellular remodeling in keratinocyte differentiation. The roles of autophagy are discussed in comparison to alternative intracellular degradation mechanisms and in the context of programmed cell death as an integral end point of epithelial differentiation. Full article

(This article belongs to the Section Autophagy)

27 pages, 787 KiB

Open AccessReview

Regulation of β-Adrenergic Receptors in the Heart: A Review on Emerging Therapeutic Strategies for Heart Failure

by Warisara Parichatikanond, Ratchanee Duangrat, Hitoshi Kurose and Supachoke Mangmool

Cells 2024, 13(20), 1674; https://doi.org/10.3390/cells13201674 (registering DOI) - 10 Oct 2024

Abstract

The prolonged overstimulation of β-adrenergic receptors (β-ARs), a member of the G protein-coupled receptor (GPCR) family, causes abnormalities in the density and functionality of the receptor and contributes to cardiac dysfunctions, leading to the development and progression of heart diseases, especially heart failure (HF). Despite recent advancements in HF therapy, mortality and morbidity rates continue to be high. Treatment with β-AR antagonists (β-blockers) has improved clinical outcomes and reduced overall hospitalization and mortality rates. However, several barriers in the management of HF remain, providing opportunities to develop new strategies that focus on the functions and signal transduction of β-ARs involved in the pathogenesis of HF. As β-AR can signal through multiple pathways influenced by different receptor subtypes, expression levels, and signaling components such as G proteins, G protein-coupled receptor kinases (GRKs), β-arrestins, and downstream effectors, it presents a complex mechanism that could be targeted in HF management. In this narrative review, we focus on the regulation of β-ARs at the receptor, G protein, and effector loci, as well as their signal transductions in the physiology and pathophysiology of the heart. The discovery of potential ligands for β-AR that activate cardioprotective pathways while limiting off-target signaling is promising for the treatment of HF. However, applying findings from preclinical animal models to human patients faces several challenges, including species differences, the genetic variability of β-ARs, and the complexity and heterogeneity of humans. In this review, we also summarize recent updates and future research on the regulation of β-ARs in the molecular basis of HF and highlight potential therapeutic strategies for HF. Full article

(This article belongs to the Special Issue The Interplay of G-Protein-Coupled Receptor Signaling between Humans and Diseases)

26 pages, 10057 KiB

Open AccessArticle

EF24, a Curcumin Analog, Reverses Interleukin-18-Induced miR-30a or miR-342-Dependent TRAF3IP2 Expression, RECK Suppression, and the Proinflammatory Phenotype of Human Aortic Smooth Muscle Cells

by Yusuke Higashi, Ryan Dashek, Patrice Delafontaine, Randy Scott Rector and Bysani Chandrasekar

Cells 2024, 13(20), 1673; https://doi.org/10.3390/cells13201673 - 10 Oct 2024

Abstract

Curcumin, a polyphenolic compound derived from the widely used spice Curcuma longa, has shown anti-atherosclerotic effects in animal models and cultured vascular cells. Inflammation is a major contributor to atherosclerosis development and progression. We previously reported that the induction of the proinflammatory molecule TRAF3IP2 (TRAF3 Interacting Protein 2) or inhibition of the matrix metallopeptidase (MMP) regulator RECK (REversion Inducing Cysteine Rich Protein with Kazal Motifs) contributes to pro-oxidant, proinflammatory, pro-mitogenic and pro-migratory effects in response to external stimuli in vascular smooth muscle cells. Here we hypothesized that EF24, a curcumin analog with a better bioavailability and bioactivity profile, reverses interleukin (IL)-18-induced TRAF3IP2 induction, RECK suppression and the proinflammatory phenotype of primary human aortic smooth muscle cells (ASMC). The exposure of ASMC to functionally active recombinant human IL-18 (10 ng/mL) upregulated TRAF3IP2 mRNA and protein expression, but markedly suppressed RECK in a time-dependent manner. Further investigations revealed that IL-18 inhibited both miR-30a and miR-342 in a p38 MAPK- and JNK-dependent manner, and while miR-30a mimic blunted IL-18-induced TRAF3IP2 expression, miR-342 mimic restored RECK expression. Further, IL-18 induced ASMC migration, proliferation and proinflammatory phenotype switching, and these effects were attenuated by TRAF3IP2 silencing, and the forced expression of RECK or EF24. Together, these results suggest that the curcumin analog EF24, either alone or as an adjunctive therapy, has the potential to delay the development and progression of atherosclerosis and other vascular inflammatory and proliferative diseases by differentially regulating TRAF3IP2 and RECK expression in ASMC. Full article

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Cells, Volume 13, Issue 20 (October-2 2024) – 4 articles

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