scholarly journals The Important Role of Leptin in Modulating the Risk of Dermatological Diseases

2021 ◽  
Vol 11 ◽  
Author(s):  
Xin Su ◽  
Ye Cheng ◽  
Dong Chang

It is an indisputable fact that obesity is associated with a series of health problems. One important hallmark of obesity is excessive accumulation of lipids in the adipocyte, especially triglyceride (TG). Currently, the adipocyte has been considered not only as a huge repository of excess energy in the form of fat but also as an important source of multiple hormones and cytokines called adipokines. In obesity, the adipocyte is dysfunctional with excessive production and secretion of pro-inflammatory adipokines, such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and leptin. On the other hand, accumulating evidence has shown that leptin plays a vital role in stimulating angiogenesis, controlling lipid metabolism, and modulating the production of pro-inflammatory cytokines. Furthermore, the various activities of leptin are related to the wide distribution of leptin receptors. Notably, it has been reported that enhanced leptin levels and dysfunction of the leptin signaling pathway can influence diverse skin diseases. Recently, several studies revealed the roles of leptin in wound healing, the hair cycle, and the pathogenic development of skin diseases, such as psoriasis, lupus erythematosus, and dermatological cancers. However, the exact mechanisms of leptin in modulating the dermatological diseases are still under investigation. Therefore, in the present review, we summarized the regulatory roles of leptin in the pathological progression of diverse diseases of skin and skin appendages. Furthermore, we also provided evidence to elucidate the complicated relationship between leptin and different dermatological diseases, such as systemic lupus erythematosus (SLE), psoriasis, hidradenitis suppurativa, and some skin tumors.

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Klaudia Dopytalska ◽  
Agnieszka Baranowska-Bik ◽  
Marek Roszkiewicz ◽  
Wojciech Bik ◽  
Irena Walecka

Abstract Leptin is an adipokine, adipocyte-derived compound, which acts both as a hormone and cytokine. It is mainly synthesized by adipocytes of white adipose tissue. Leptin possesses pleiotropic functions including, among others, stimulation of angiogenesis and production of proinflammatory cytokines. The various types of leptin activity are related to the wide distribution of leptin receptors. This adipokine acts by activating intracellular signaling cascades such as JAKs (Janus kinases), STATs (signal transducers and activators of transcription), and others. In a course of obesity, an increased serum level of leptin coexists with tissue receptor resistance. It has been reported that enhanced leptin levels, leptin receptor impairment, and dysfunction of leptin signaling can influence skin and hair. The previous studies revealed the role of leptin in wound healing, hair cycle, and pathogenesis of skin diseases like psoriasis, lupus erythematosus, and skin cancers. However, the exact mechanism of leptin’s impact on the skin is still under investigation. Herein, we present the current knowledge concerning the role of leptin in psoriasis and selected skin diseases.


Author(s):  
Maryam Gholamalizadeh ◽  
Samaneh Mirzaei Dahka ◽  
Hadi Sedigh Ebrahim-Saraie ◽  
Mohammad Esmail Akbari ◽  
Azam Pourtaheri ◽  
...  

1999 ◽  
Vol 112 (21) ◽  
pp. 3603-3617 ◽  
Author(s):  
J. Schlondorff ◽  
C.P. Blobel

Metalloprotease-disintegrins (ADAMs) have captured our attention as key players in fertilization and in the processing of the ectodomains of proteins such as tumor necrosis factor (α) (TNF(α)), and because of their roles in Notch-mediated signaling, neurogenesis and muscle fusion. ADAMs are integral membrane glycoproteins that contain a disintegrin domain, which is related to snake-venom integrin ligands, and a metalloprotease domain (which can contain or lack a catalytic site). Here, we review and critically discuss current topics in the ADAMs field, including the central role of fertilin in fertilization, the role of the TNF(α) convertase in protein ectodomain processing, the role of Kuzbanian in Notch signaling, and links between ADAMs and processing of the amyloid-precursor protein.


1998 ◽  
Vol 275 (2) ◽  
pp. R502-R508 ◽  
Author(s):  
Xianzhong Meng ◽  
Lihua Ao ◽  
Daniel R. Meldrum ◽  
Brian S. Cain ◽  
Brian D. Shames ◽  
...  

Exogenous tumor necrosis factor-α (TNF-α) induces delayed myocardial depression in vivo but promotes rapid myocardial depression in vitro. The temporal relationship between endogenous TNF-α and endotoxemic myocardial depression is unclear, and the role of TNF-α in this myocardial disorder remains controversial. Using a rat model of endotoxemia not complicated by shock, we sought to determine 1) the temporal relationship of changes in circulating and myocardial TNF-α with myocardial depression, 2) the influences of protein synthesis inhibition or immunosuppression on TNF-α production and myocardial depression, and 3) the influence of neutralization of TNF-α on myocardial depression. Rats were treated with lipopolysaccharide (LPS, 0.5 mg/kg ip). Circulating and myocardial TNF-α increased at 1 and 2 h, whereas myocardial contractility was depressed at 4 and 6 h. Pretreatment with cycloheximide or dexamethasone abolished the increase in circulating and myocardial TNF-α and preserved myocardial contractile function. Similarly, treatment with TNF binding protein immediately after LPS prevented myocardial depression. We conclude that endogenous TNF-α mediates delayed myocardial depression in endotoxemic rats and that inhibition of TNF-α production or neutralization of TNF-α preserves myocardial contractile function in endotoxemia.


2005 ◽  
Vol 33 (04) ◽  
pp. 547-557 ◽  
Author(s):  
Jae-Young Um ◽  
Jae-Heung Lee ◽  
Jong-Cheon Joo ◽  
Kyung-Yo Kim ◽  
Eun-Hee Lee ◽  
...  

During the last decade, a growing corpus of evidence has indicated an important role of cytokines in the development of brain damage following cerebral ischemia. Tumor necrosis factor-α (TNF-α), a potent immunomodulator and pro-inflammatory cytokine, has been implicated in many pathological processes. In this study, we examined whether promoter region polymorphism in the TNF-α gene at position –308 affects the odds of cerebral infarction (CI) and whether genetic risk is enhanced by Sasang constitutional classification. Two hundred and twelve CI patients and 610 healthy controls were genotyped and determined according to Sasang constitutional classification. A significant decrease was found for the TNF-α A allele in CI patients compared with controls ( p = 0.033, odds ratio, OR: 0.622). However, there was no significant association between TNF-α polymorphism and Sasang constitution in CI patients. Our finding suggests that TNF-α promoter region polymorphism is responsible for susceptibility to CI in Koreans.


2020 ◽  
Vol 318 (4) ◽  
pp. H1018-H1027 ◽  
Author(s):  
Jeremy W. Duncan ◽  
Subhi Talal Younes ◽  
Emily Hildebrandt ◽  
Michael J. Ryan ◽  
Joey P. Granger ◽  
...  

Preeclampsia is a pregnancy-related disorder characterized by hypertension, vascular dysfunction and an increase in circulating inflammatory factors including the cytokine, tumor necrosis factor-α (TNF-α). Studies have shown that placental ischemia is associated with 1) increased circulating TNF-α, 2) attenuated pressure-induced cerebral vascular tone, and 3) suppression of β-epithelial Na+ channel (βENaC) protein in cerebral vessels. In addition to its role in epithelial Na+ and water transport, βENaC is an essential signaling element in transduction of pressure-induced (aka “myogenic”) constriction, a critical mechanism of blood flow autoregulation. While cytokines inhibit expression of certain ENaC proteins in epithelial tissue, it is unknown if the increased circulating TNF-α associated with placental ischemia mediates the loss of cerebrovascular βENaC and cerebral blood flow regulation. Therefore, the purpose of this study was to test the hypothesis that increasing plasma TNF-α in normal pregnant rats reduces cerebrovascular βENaC expression and impairs cerebral blood flow (CBF) regulation. In vivo TNF-α infusion (200 ng/day, 5 days) inhibited cerebrovascular expression of βENaC and impaired CBF regulation in pregnant rats. To determine the direct effects of TNF-α and underlying pathways mediating vascular smooth muscle cell βENaC reduction, we exposed cultured VSMCs (A10 cell line) to TNF-α (1–100 ng/mL) for 16–24 h. TNF-α reduced βENaC protein expression in a concentration-dependent fashion from 0.1 to 100 ng/mL, without affecting cell death. To assess the role of canonical MAPK signaling in this response, VSMCs were treated with p38MAPK or c-Jun kinase (JNK) inhibitors in the presence of TNF-α. We found that both p38MAPK and JNK blockade prevented TNF-α-mediated βENaC protein suppression. These data provide evidence that disorders associated with increased circulating TNF-α could lead to impaired cerebrovascular regulation, possibly due to reduced βENaC-mediated vascular function. NEW & NOTEWORTHY This manuscript identifies TNF-α as a possible placental-derived cytokine that could be involved in declining cerebrovascular health observed in preeclampsia. We found that infusion of TNF-α during pregnancy impaired cerebral blood flow control in rats at high arterial pressures. We further discovered that cerebrovascular β-epithelial sodium channel (βENaC) protein, a degenerin protein involved in mechanotransduction, was reduced by TNF-α in pregnant rats, indicating a potential link between impaired blood flow and this myogenic player. We next examined this effect in vitro using a rat vascular smooth muscle cell line. TNF-α reduced βENaC through canonical MAPK-signaling pathways and was not dependent on cell death. This study demonstrates the pejorative effects of TNF-α on cerebrovascular function during pregnancy and warrants future investigations to study the role of cytokines on vascular function during pregnancy.


2020 ◽  
Vol 7 (2) ◽  
pp. 57
Author(s):  
Eric Danilo Pauls Sotelo ◽  
Cynthia Prado Vendruscolo ◽  
Joice Fülber ◽  
Sarah Raphaela Torquato Seidel ◽  
Fernando Mosquera Jaramillo ◽  
...  

Several studies in human and equine medicine have produced controversial results regarding the role of dimethylsulfoxide (DMSO) as a therapeutic agent. This study aimed to evaluate the effect of joint lavage with different DMSO concentrations on biomarkers of synovial fluid inflammation and cartilage degradation in joints with lipopolysaccharide (LPS)-induced synovitis. Twenty-six tibiotarsal joints of 13 horses were randomly distributed into four groups (lactated Ringer’s solution; 5% DMSO in lactated Ringer’s; 10% DMSO in lactated Ringer’s; and sham). All animals were evaluated for the presence of lameness, and synovial fluid analyses were performed at 0 h, 1 h, 8 h, 24 h, and 48 h (T0, T1, T8, T24, and T48, respectively). The white blood cell counts (WBC), total protein (TP), urea, prostaglandin E2 (PGE2), interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor-α (TNF-α), hyaluronic acid (HA), and chondroitin sulfate (CS) concentrations were measured. The WBC counts and PGE2, IL-1β, IL-6, and TP concentrations increased in all groups at T8 compared to baseline values (p < 0.05). At T48, only the 5% DMSO and 10% DMSO groups showed a significant decrease in WBC counts (p < 0.05). Furthermore, the 10% DMSO group had lower concentrations of PGE2 and IL-1β at T48 than at T8 (p < 0.05) and presented lower IL-6 levels than the5% DMSO and lactated Ringer’s groups at T24. All groups showed an increase in CS concentration after LPS-induced synovitis. Joint lavage with 10% DMSO in lactated Ringer’s has anti-inflammatory but not chondroprotective effects.


2017 ◽  
Vol 9 ◽  
pp. 117957351772251 ◽  
Author(s):  
Daniah Shamim ◽  
Michael Laskowski

Tumor necrosis factor α (TNF-α) inhibitors have long been used as disease-modifying agents in immune disorders. Recently, research has shown a role of chronic neuroinflammation in the pathophysiology of neurodegenerative diseases such as Alzheimer disease, and interest has been generated in the use of anti-TNF agents and TNF-modulating agents for prevention and treatment. This article extensively reviewed literature on animal studies testing these agents. The results showed a role for direct and indirect TNF-α inhibition through agents such as thalidomide, 3,6-dithiothalidomide, etanercept, infliximab, exendin-4, sodium hydrosulfide, minocycline, imipramine, and atorvastatin. Studies were performed on mice, rats, and monkeys, with induction of neurodegenerative physiology either through the use of chemical agents or through the use of transgenic animals. Most of these agents showed an improvement in cognitive function as tested with the Morris water maze, and immunohistochemical and histopathological staining studies consistently showed better outcomes with these agents. Brains of treated animals showed significant reduction in pro-inflammatory TNF-α and reduced the burden of neurofibrillary tangles, amyloid precursor protein, and β-amyloid plaques. Also, recruitment of microglial cells in the central nervous system was significantly reduced through these drugs. These studies provide a clearer mechanistic understanding of the role of TNF-α modulation in Alzheimer disease. All studies in this review explored the use of these drugs as prophylactic agents to prevent Alzheimer disease through immune modulation of the TNF inflammatory pathway, and their success highlights the need for further research of these drugs as therapeutic agents.


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