The Role of Host Defense Peptide Human β-defensins in the Maintenance of Skin Barriers

2018 ◽  
Vol 24 (10) ◽  
pp. 1092-1099 ◽  
Author(s):  
Chanisa Kiatsurayanon ◽  
Hideoki Ogawa ◽  
Francois Niyonsaba
Keyword(s):  
Host Defense ◽  
Current Knowledge ◽  
Skin Barrier ◽  
Skin Inflammation ◽  
The Body ◽  
Skin Barrier Function ◽  
Host Defense Peptides ◽  
Host Defense Peptide ◽  
Novel Therapeutic Strategies

The epidermis functions as a first-line defense barrier that protects the body from the external environment. As a chemical hindrance, the epidermis possesses acidic pH, highly organized lipids and various host defense peptides, also known as antimicrobial peptides. Human β-defensins (hBDs), one of the most important host defense peptide families found in our skin, are well-known for their broad-spectrum microbicidal activities. However, there is a growing body of evidence indicating that hBDs also orchestrate several immunomodulatory functions and are the cornerstone that bridges the innate and adaptive immune responses during skin inflammation and infection. Moreover, recent work identified the potential role of hBDs in the regulation and maintenance of the skin barrier function. In this review, we describe the current knowledge concerning the role of hBDs in skin barriers and discuss the potential clinical implications of these peptides in cutaneous biology. Understanding the roles of hBDs in the regulation and maintenance of skin barriers may aid in the development of novel therapeutic strategies for skin conditions where the skin barrier is impaired, such as atopic dermatitis and psoriasis.

scholarly journals Stress and Skin: An Overview of Mind Body Therapies as a Treatment Strategy in Dermatology

2021 ◽  
pp. e2021091
Author(s):  
Rachel Graubard ◽  
Ariadna Perez-Sanchez ◽  
Rajani Katta
Keyword(s):  
Stress Response ◽  
Skin Disease ◽  
Skin Barrier ◽  
Psychosocial Outcomes ◽  
Skin Inflammation ◽  
The Body ◽  
Skin Barrier Function ◽  
Beneficial Effects ◽  
Potential Benefits ◽  
The Mind

Stress has multiple and wide-ranging physiologic and clinical impacts on skin disease. This has led to an interest in mind body therapies as potential adjunct treatments for skin disease. The stress response results in the activation of the endocrine, neurologic, and immune systems, with a resulting cascade of impacts, that are both systemic and cutaneous. The 2 main arms of the stress response are the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis. The resultant release of cortisol, catecholamines, and neuropeptides has multiple effects. Clinically, these have been shown to increase skin inflammation, increase itching, impair skin barrier function, impair wound healing, and suppress immunity.Mind body therapies are those that focus on the interaction between the mind and the body, with the goal to influence physical function and impact health. These have been shown to ameliorate some of the harmful physiologic changes attributed to stress or to reduce harmful behaviors. In some cases, such as with biofeedback, they may also result in beneficial physiologic changes. Treatments such as meditation, biofeedback, hypnosis, guided imagery, and others have been evaluated in the treatment of skin disease and have shown some benefits. Although randomized controlled trials are limited, these interventions have shown beneficial effects on itching, psychosocial outcomes, and even skin severity. These interventions have been evaluated in diseases such as atopic dermatitis, psoriasis, trichotillomania, and others. Given the potential benefits, improvements in psychosocial outcomes, and a low risk profile, referral to qualified practitioners or multidisciplinary clinics should be considered for some patients.

scholarly journals Role of AHR Ligands in Skin Homeostasis and Cutaneous Inflammation

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3176
Author(s):  
Nieves Fernández-Gallego ◽  
Francisco Sánchez-Madrid ◽  
Danay Cibrian
Keyword(s):  
Atopic Dermatitis ◽  
Barrier Function ◽  
Inflammatory Responses ◽  
Normal Skin ◽  
Skin Barrier ◽  
Skin Inflammation ◽  
In Vitro Assays ◽  
Skin Barrier Function

Aryl hydrocarbon receptor (AHR) is an important regulator of skin barrier function. It also controls immune-mediated skin responses. The AHR modulates various physiological functions by acting as a sensor that mediates environment–cell interactions, particularly during immune and inflammatory responses. Diverse experimental systems have been used to assess the AHR’s role in skin inflammation, including in vitro assays of keratinocyte stimulation and murine models of psoriasis and atopic dermatitis. Similar approaches have addressed the role of AHR ligands, e.g., TCDD, FICZ, and microbiota-derived metabolites, in skin homeostasis and pathology. Tapinarof is a novel AHR-modulating agent that inhibits skin inflammation and enhances skin barrier function. The topical application of tapinarof is being evaluated in clinical trials to treat psoriasis and atopic dermatitis. In the present review, we summarize the effects of natural and synthetic AHR ligands in keratinocytes and inflammatory cells, and their relevance in normal skin homeostasis and cutaneous inflammatory diseases.

scholarly journals The Implications of Pruritogens in the Pathogenesis of Atopic Dermatitis

2021 ◽  
Vol 22 (13) ◽  
pp. 7227
Author(s):  
Lai-San Wong ◽  
Yu-Ta Yen ◽  
Chih-Hung Lee
Keyword(s):  
Atopic Dermatitis ◽  
Environmental Factors ◽  
Immune Responses ◽  
Immune Cells ◽  
Inflammatory Disease ◽  
Targeted Therapies ◽  
Skin Barrier ◽  
Skin Barrier Function ◽  
Inflammatory Molecules

Atopic dermatitis (AD) is a prototypic inflammatory disease that presents with intense itching. The pathophysiology of AD is multifactorial, involving environmental factors, genetic susceptibility, skin barrier function, and immune responses. A recent understanding of pruritus transmission provides more information about the role of pruritogens in the pathogenesis of AD. There is evidence that pruritogens are not only responsible for eliciting pruritus, but also interact with immune cells and act as inflammatory mediators, which exacerbate the severity of AD. In this review, we discuss the interaction between pruritogens and inflammatory molecules and summarize the targeted therapies for AD.

scholarly journals Metabolic Acidosis in Patients with CKD: Epidemiology, Pathogenesis, and Treatment

2021 ◽  
pp. 1-16
Author(s):  
Marcin Adamczak ◽  
Stanisław Surma
Keyword(s):  
Metabolic Acidosis ◽  
Sodium Bicarbonate ◽  
Current Knowledge ◽  
Venous Blood ◽  
The Body ◽  
Hydrogen Ions ◽  
Ckd Progression ◽  
New Drug ◽  
Treatment And Prevention

<b><i>Background:</i></b> Metabolic acidosis in CKD is diagnosed in patients with plasma or venous blood bicarbonate concentration lower than 22 mmol/L. Metabolic acidosis occurs in about 20% of patients with CKD. Metabolic acidosis may lead to dysfunction of many systems and organs as well as CKD progression. Currently, sodium bicarbonate is mainly used for pharmacological treatment of metabolic acidosis in patients with CKD. Veverimer is a new drug dedicated to treatment of metabolic acidosis in patients with CKD. Orally given veverimer binds hydrogen ions in the intestines and subsequently is excreted from the body with feces. Clinical studies have shown that veverimer is effective in increasing serum bicarbonate concentrations in CKD patients with metabolic acidosis. Here, we present review of the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients. <b><i>Summary:</i></b> Metabolic acidosis is common in patients with CKD and contributes to CKD progression and many complications, which worsen the prognosis in these patients. Currently, sodium bicarbonate is mainly used in metabolic acidosis treatment. The role of the new drug veverimer in the metabolic acidosis therapy needs further studies. <b><i>Key Message:</i></b> The aim of this review article is to summarize the current knowledge concerning the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients.

Role of the gut microbiota in airway immunity and host defense against respiratory infections

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maike Willers ◽  
Dorothee Viemann
Keyword(s):  
Gut Microbiota ◽  
Host Defense ◽  
Gut Microbiome ◽  
Respiratory Infections ◽  
Current Knowledge ◽  
Viral Pathogens ◽  
Commensal Microbiota ◽  
Enhanced Resistance ◽  
The Impact

Abstract Colonization of the intestine with commensal bacteria is known to play a major role in the maintenance of human health. An altered gut microbiome is associated with various ensuing diseases including respiratory diseases. Here, we summarize current knowledge on the impact of the gut microbiota on airway immunity with a focus on consequences for the host defense against respiratory infections. Specific gut commensal microbiota compositions and functions are depicted that mediate protection against respiratory infections with bacterial and viral pathogens. Lastly, we highlight factors that have imprinting effects on the establishment of the gut microbiota early in life and are potentially relevant in the context of respiratory infections. Deepening our understanding of these relationships will allow to exploit the knowledge on how gut microbiome maturation needs to be modulated to ensure lifelong enhanced resistance towards respiratory infections.

scholarly journals Human β-Defensin 3 Inhibits Cell Wall Biosynthesis in Staphylococci

2010 ◽  
Vol 78 (6) ◽  
pp. 2793-2800 ◽  
Author(s):  
Vera Sass ◽  
Tanja Schneider ◽  
Miriam Wilmes ◽  
Christian Körner ◽  
Alessandro Tossi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Host Defense ◽  
Transcriptional Response ◽  
Cell Wall Biosynthesis ◽  
Host Defense Peptides ◽  
Lipid Ii ◽  
Transmission Electron ◽  
Host Defense Peptide

ABSTRACT Human β-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions.

scholarly journals Host Defense Peptides in the Oral Cavity and the Lung: Similarities and Differences

2008 ◽  
Vol 87 (10) ◽  
pp. 915-927 ◽  
Author(s):  
G. Diamond ◽  
N. Beckloff ◽  
L.K. Ryan
Keyword(s):  
Oral Cavity ◽  
Host Defense ◽  
Gingival Crevicular Fluid ◽  
Immune Defense ◽  
The Body ◽  
Microbial Colonization ◽  
Host Defense Peptides ◽  
Innate Defense ◽  
Defense Peptides

Peptides with broad-spectrum antimicrobial activity are found in the mucosal surfaces at many sites in the body, including the airway, the oral cavity, and the digestive tract. Based on their in vitro antimicrobial and other immunomodulatory activities, these host defense peptides have been proposed to play an important role in the innate defense against pathogenic microbial colonization. The genes that encode these peptides are up-regulated by pathogens, further supporting their role in innate immune defense. However, the differences in the local microbial environments between the generally sterile airway and the highly colonized oral cavity suggest a more complex role for these peptides in innate immunity. For example, β-defensin genes are induced in the airway by all bacteria and Toll-like receptor (TLR) agonists primarily through an NF-κB-mediated pathway. In contrast, the same genes are induced in the gingival epithelium by only a subset of bacteria and TLR ligands, via different pathways. Furthermore, the environments into which the peptides are secreted—specifically saliva, gingival crevicular fluid, and airway surface fluid—differ greatly and can effect their respective activities in host defense. In this review, we examine the differences and similarities between host defense peptides in the oral cavity and the airway, to gain a better understanding of their contributions to immunity.

scholarly journals Neuroinflammation as Fuel for Axonal Regeneration in the Injured Vertebrate Central Nervous System

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ilse Bollaerts ◽  
Jessie Van houcke ◽  
Lien Andries ◽  
Lies De Groef ◽  
Lieve Moons
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Axonal Regeneration ◽  
Current Knowledge ◽  
Cord Injury ◽  
The Central Nervous System ◽  
Novel Therapeutic Strategies ◽  
The Impact ◽  
Vertebrate Central Nervous System

Damage to the central nervous system (CNS) is one of the leading causes of morbidity and mortality in elderly, as repair after lesions or neurodegenerative disease usually fails because of the limited capacity of CNS regeneration. The causes underlying this limited regenerative potential are multifactorial, but one critical aspect is neuroinflammation. Although classically considered as harmful, it is now becoming increasingly clear that inflammation can also promote regeneration, if the appropriate context is provided. Here, we review the current knowledge on how acute inflammation is intertwined with axonal regeneration, an important component of CNS repair. After optic nerve or spinal cord injury, inflammatory stimulation and/or modification greatly improve the regenerative outcome in rodents. Moreover, the hypothesis of a beneficial role of inflammation is further supported by evidence from adult zebrafish, which possess the remarkable capability to repair CNS lesions and even restore functionality. Lastly, we shed light on the impact of aging processes on the regenerative capacity in the CNS of mammals and zebrafish. As aging not only affects the CNS, but also the immune system, the regeneration potential is expected to further decline in aged individuals, an element that should definitely be considered in the search for novel therapeutic strategies.

Renal interstitial hyaluronan: functional aspects during normal and pathological conditions

2012 ◽  
Vol 302 (11) ◽  
pp. R1235-R1249 ◽  
Author(s):  
Sara Stridh ◽  
Fredrik Palm ◽  
Peter Hansell
Keyword(s):  
Current Knowledge ◽  
Stone Formation ◽  
Ischemia Reperfusion ◽  
The Body ◽  
Receptor Expression ◽  
Whole Body ◽  
Hydration Status ◽  
Hyaluronan Synthases ◽  
Pathological Conditions

The glycosaminoglycan (GAG) hyaluronan (HA) is recognized as an important structural component of the extracellular matrix, but it also interacts with cells during embryonic development, wound healing, inflammation, and cancer; i.e., important features in normal and pathological conditions. The specific physicochemical properties of HA enable a unique hydration capacity, and in the last decade it was revealed that in the interstitium of the renal medulla, where the HA content is very high, it changes rapidly depending on the body hydration status while the HA content of the cortex remains unchanged at very low amounts. The kidney, which regulates fluid balance, uses HA dynamically for the regulation of whole body fluid homeostasis. Renomedullary HA elevation occurs in response to hydration and during dehydration the opposite occurs. The HA-induced alterations in the physicochemical characteristics of the interstitial space affects fluid flux; i.e., reabsorption. Antidiuretic hormone, nitric oxide, angiotensin II, and prostaglandins are classical hormones/compounds involved in renal fluid handling and are important regulators of HA turnover during variations in hydration status. One major producer of HA in the kidney is the renomedullary interstitial cell, which displays receptors and/or synthesis enzymes for the hormones mentioned above. During several kidney disease states, such as ischemia-reperfusion injury, tubulointerstitial inflammation, renal transplant rejection, diabetes, and kidney stone formation, HA is upregulated, which contributes to an abnormal phenotype. In these situations, cytokines and other growth factors are important stimulators. The immunosuppressant agent cyclosporine A is nephrotoxic and induces HA accumulation, which could be involved in graft rejection and edema formation. The use of hyaluronidase to reduce pathologically overexpressed levels of tissue HA is a potential therapeutic tool since diuretics are less efficient in removing water bound to HA in the interstitium. Although the majority of data describing the role of HA originate from animal and cell studies, the available data from humans demonstrate that an upregulation of HA also occurs in diabetic kidneys, in transplant-rejected kidneys, and during acute tubular necrosis. This review summarizes the current knowledge regarding interstitial HA in the role of regulating kidney function during normal and pathological conditions. It encompasses mechanistic insights into the background of the heterogeneous intrarenal distribution of HA; i.e., late nephrogenesis, its regulation during variations in hydration status, and its involvement during several pathological conditions. Changes in hyaluronan synthases, hyaluronidases, and binding receptor expression are discussed in parallel.

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