Application of Topical Sandalore® Increases Epidermal Dermcidin Synthesis in Organ-Cultured Human Skin ex vivo.

INTRODUCTION: Several olfactory receptors (ORs) are expressed in human skin, where they regulate skin pigmentation, barrier function, wound healing, and hair growth. Previously, we found that the selective activation of OR family 2 subfamily AT member 4 (OR2AT4) by the synthetic, sandalwood-like odorant Sandalore® differentially stimulates the expression of antimicrobial peptides (AMPs) in human scalp hair follicle epithelium ex vivo. As OR2AT4 is also expressed by epidermal keratinocytes, we hypothesized that it may modulate intraepidermal AMP synthesis, thereby contributing to skin microbiome management. METHODS: We investigated this hypothesis in organ-cultured human skin in the presence of Sandalore® and antibiotics and evaluated epidermal production of two AMPs, LL37 (cathelicidin) and dermcidin (DCD), as well as OR2AT4, by quantitative immunohistomorphometry. Moreover, we quantified DCD secretion into the culture medium by ELISA and studied the effect of culture medium on selected bacterial and fungal strains. RESULTS: Topical application of Sandalore®to organ-cultured human skin increased OR2AT4 protein expression, the number of DCD-positive intraepidermal cells, and DCD secretion into culture media, without significantly affecting epidermal LL37 expression. In line with the significantly increased secretion of DCD into the culture medium, we demonstrated, in a spectrophotometric assay, that application of conditioned media from Sandalore®-treated skin promotes Staphylococcus epidermidis, Malassezia restricta, and, minimally, Cutibacterium acnes and inhibits Staphylococcus aureus growth. CONCLUSION: In addition to demonstrating for the first time that DCD can be expressed by epidermal keratinocytes, our pilot study suggests that topical treatment of human skin with a cosmetic odorant (Sandalore®) has the potential to alter the composition of the human skin microbiome through the selective upregulation of DCD. If confirmed, Sandalore® could become an attractive adjuvant, nondrug treatment for dermatoses characterized by dysbiosis due to overgrowth of S. aureus and Malassezia, such as atopic dermatitis and seborrheic dermatitis.

Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1L against Acinetobacter baumannii: an in vivo wound healing model.

BACKGROUND: The global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii. METHODS: After determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed. RESULTS: The bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L. CONCLUSIONS: Results of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.

Preclinical Development of Seriniquinones as Selective Dermcidin Modulators for the Treatment of Melanoma.

The bioactive natural product seriniquinone was discovered as a potential melanoma drug, which was produced by the as-yet-undescribed marine bacterium of the rare genus Serinicoccus. As part of a long-term research program aimed at the discovery of new agents for the treatment of cancer, seriniquinone revealed remarkable in vitro activity against a diversity of cancer cell lines in the US National Cancer Institute 60-cell line screening. Target deconvolution studies defined the seriniquinones as a new class of melanoma-selective agents that act in part by targeting dermcidin (DCD). The targeted DCD peptide has been recently examined and defined as a "pro-survival peptide" in cancer cells. While DCD was first isolated from human skin and thought to be only an antimicrobial peptide, currently DCD has been also identified as a peptide associated with the survival of cancer cells, through what is believed to be a disulfide-based conjugation with proteins that would normally induce apoptosis. However, the significantly enhanced potency of seriniquinone was of particular interest against the melanoma cell lines assessed in the NCI 60-cell line panel. This observed selectivity provided a driving force that resulted in a multidimensional program for the discovery of a usable drug with a new anticancer target and, therefore, a novel mode of action. Here, we provided an overview of the discovery and development efforts to date.

Proceeding report of the Fourth Symposium on Hidradenitis Suppurativa Advances 2019.

The Fourth Annual Symposium on Hidradenitis Suppurativa (SHSA) took place on November 1-3, 2019, at the Westin Book Cadillac Hotel in Detroit, Michigan. This symposium was a joint meeting of the US Hidradenitis Suppurativa Foundation and the Canadian Hidradenitis Suppurativa Foundation. This cross-disciplinary meeting with experts from around the world was an opportunity to discuss the most recent advances in the study of hidradenitis suppurativa (HS) pathogenesis, clinical trials, classification, scoring systems, complementary/alternative medical treatments, diet, pain management, surgical and laser treatment, and ultrasonographic assessment. A special preconference workshop was held on the use of neodymium-doped yttrium-aluminum-garnet laser hair reduction, sinus tract deroofing, and carbon dioxide laser excision with ultrasonographic mapping and tumescent anesthesia for the treatment of HS. The focused workshops on establishing an HS clinic, setting up an HS support group, the Hidradenitis Suppurativa Prospective Observational Registry and Biospecimen Repository, and wound care were held during the meeting. A special program called HS Ambassadors was established for patients who may have questions about the conference presentations, and in addition, a meet and greet for patients and HS Ambassadors was arranged. To facilitate networking between those early in their careers and clinical and research experts, a mentoring reception was held.

Seriniquinones as Therapeutic Leads for Treatment of BRAF and NRAS Mutant Melanomas.

Isolated from the marine bacteria Serinicoccus sp., seriniquinone (SQ1) has been characterized by its selective activity in melanoma cell lines marked by its modulation of human dermcidin and induction of autophagy and apoptosis. While an active lead, the lack of solubility of SQ1 in both organic and aqueous media has complicated its preclinical evaluation. In response, our team turned its effort to explore analogues with the goal of returning synthetically accessible materials with comparable selectivity and activity. The analogue SQ2 showed improved solubility and reached a 30-40-fold greater selectivity for melanoma cells. Here, we report a detailed comparison of the activity of SQ1 and SQ2 in SK-MEL-28 and SK-MEL-147 cell lines, carrying the top melanoma-associated mutations, BRAFV600E and NRASQ61R, respectively. These studies provide a definitive report on the activity, viability, clonogenicity, dermcidin expression, autophagy, and apoptosis induction following exposure to SQ1 or SQ2. Overall, these studies showed that SQ1 and SQ2 demonstrated comparable activity and modulation of dermcidin expression. These studies are further supported through the evaluation of a panel of basal expression of key-genes related to autophagy and apoptosis, providing further insight into the role of these mutations. To explore this rather as a survival or death mechanism, autophagy inhibition sensibilized BRAF mutants to SQ1 and SQ2, whereas the opposite happened to NRAS mutants. These data suggest that the seriniquinones remain active, independently of the melanoma mutation, and suggest the future combination of their application with inhibitors of autophagy to treat BRAF-mutated tumors.

Plasma dermcidin levels in acne patients, and the effect of isotretinoin treatment on dermcidin levels.

Acne vulgaris is a chronic inflammatory disease of the pilosebaceous unit. Dermcidin (DCD) is an antimicrobial peptide released from eccrine sweat glands and sebaceous glands. Studies investigating the role of DCD expression in acne development are scarce. The aim of this study was to determine the relationship between DCD expression and acne vulgaris and the effect of oral isotretinoin treatment on DCD levels. Two groups (one patient group and one control group) were included in the study. The patient group consisted of 30 patients with acne vulgaris who were given oral isotretinoin treatment for 6 months until the cumulative dose was attained. Plasma DCD levels were investigated before and 6 months after treatment. The control group comprised 30 volunteer individuals without acne vulgaris or any inflammatory dermatosis. Of the patients, 24 (80%) had Grade 3, 3 (10%) had Grade 1, and 3 (10%) had Grade 4 acne vulgaris, as determined according to the Pillsbury scoring method. The DCD levels in the control group were significantly higher than those in pretreatment patients (39.53 ± 20.2 vs. 28.60 ± 20.12, p = .004). Additionally, pretreatment DCD levels were significantly increased after 6 months of isotretinoin treatment in the patient group (28.60 ± 20.12 vs. 35.07 ± 24.02, p = .012). The mean pretreatment global acne grading system score of 20.86 ± 4.43 was decreased to 5.17 ± 1.91 in patients after treatment (p < .001). This study indicated that DCD plays an important role in the pathogenesis of acne. It demonstrates anti-inflammatory properties in acne vulgaris. Moreover, it was shown that isotretinoin treatment may improve acne vulgaris by increasing DCD levels.

A novel method to assess the potential role of sweating abnormalities in the pathogenesis of atopic dermatitis.

Although atopic dry skin is believed to be caused by defects in skin genes important for maintaining skin barrier function, the role of sweat in atopic dermatitis (AD) has been apparently underestimated. Given the great capacity of sweat to maintain and increase skin hydration, defective sweating responses may be a logical place to look for changes that predispose individuals to the disease. We investigated how disease process and sweating defects progress from early asymptomatic stages to the onset of clinically apparent disease by employing the impression mould technique, which allows an accurate quantification of individual sweat gland/duct activity in relation to skin surface topography. Insensible and sensible sweating responses under baseline conditions and after thermal stimulus, respectively, were measured in various stages of AD patients and healthy controls. In controls, under baseline conditions, sweat ducts/glands at the dermal folds secreted basal levels of sweat (insensible sweating), thereby maintaining skin hydration. Not only such insensible sweating but also sensible sweating markedly decreased even in the earliest asymptomatic stage and the decrease was followed by compensatory hyperhidrosis at the ridge: leakage of sweat into the dermis could represent the initial event resulting in the decreased sweating and inflammation. The defects eventually progressed involving all of the ducts/glands to develop systemic dry skin. AD skin is characterized by varying degrees of functional impairment of sweat ducts/glands depending on the stage, and this defect would be among the reasons for the inability of AD patients to maintain skin hydration.

Structure analysis of the membrane-bound dermcidin-derived peptide SSL-25 from human sweat.

SSL-25 (SSLLEKGLDGAKKAVGGLGKLGKDA) is one of the shortest peptides present in human sweat and is produced after the proteolytic processing of the parent peptide dermcidin. Both peptides are reported to have antimicrobial function. To determine the structure of SSL-25 in lipid bilayers, a series of 19F-labeled SSL-25 analogs were synthesized. Circular dichroism (CD) analysis showed that SSL-25 and all of its analogs formed α-helices in the presence of lipid vesicles, thus allowing a detailed analysis via oriented CD and solid-state NMR. The results suggest that SSL-25 resides on the membrane surface with a slight helix tilt angle. A detailed 19F NMR analysis revealed that SSL-25 does not form a continuous helix. The α-helical structure of the N-terminal part of the peptide was preserved in membranes of different lipid compositions and at various peptide-to-lipid molar ratios, but the C-terminus was disordered and did not fold into a well-defined α-helical conformation. Furthermore, the NMR results showed that SSL-25 resides on the membrane surface and does not re-orient into the membrane in response to changes in either peptide concentration or membrane composition. SSL-25 does not aggregate and remains fully mobile within the membrane bilayer, as shown by 19F NMR. SSL-25 has a high binding affinity toward bilayers mimicking bacterial lipid compositions, but does not bind to mammalian model membranes containing cholesterol. These observations may explain the selectivity of this peptide for bacterial membranes, and they are also in line with basic biophysical considerations on spontaneous lipid curvature and the general effect of cholesterol on peptide/lipid interactions.

Vitronectin and dermcidin serum levels predict the metastatic progression of AJCC I-II early-stage melanoma.

Like many cancers, an early diagnosis of melanoma is fundamental to ensure a good prognosis, although an important proportion of stage I-II patients may still develop metastasis during follow-up. The aim of this work was to discover serum biomarkers in patients diagnosed with primary melanoma that identify those at a high risk of developing metastasis during the follow-up period. Proteomic and mass spectrophotometry analysis was performed on serum obtained from patients who developed metastasis during the first years after surgery for primary tumors and compared with that from patients who remained disease-free for more than 10 years after surgery. Five proteins were selected for validation as prognostic factors in 348 melanoma patients and 100 controls by ELISA: serum amyloid A and clusterin; immune system proteins; the cell adhesion molecules plakoglobin and vitronectin and the antimicrobial protein dermcidin. Compared to healthy controls, melanoma patients have high serum levels of these proteins at the moment of melanoma diagnosis, although the specific values were not related to the histopathological stage of the tumors. However, an analysis based on classification together with multivariate statistics showed that tumor stage, vitronectin and dermcidin levels were associated with the metastatic progression of patients with early-stage melanoma. Although melanoma patients have increased serum dermcidin levels, the REPTree classifier showed that levels of dermcidin <2.98 µg/ml predict metastasis in AJCC stage II patients. These data suggest that vitronectin and dermcidin are potent biomarkers of prognosis, which may help to improve the personalized medical care of melanoma patients and their survival.

IGF1 stabilizes sperm membrane proteins to reduce cryoinjury and maintain post-thaw sperm motility in buffalo (Bubalus bubalis) spermatozoa.

Insulin like growth factor 1 (IGF1) in the seminal plasma is reported to improve sperm motility by reducing oxidative stress. The present study was conducted to assess the effect of addition of IGF1 on sperm function and protein composition during cryopreservation process. Semen samples were collected from six Murrah buffaloes (2 ejaculates from each animal) and diluted (80 million/ml) in tris egg yolk extender and divided into control, T1, T2 and T3, groups supplemented with 0, 50, 100 and 150 ng of IGF1/mL, respectively. The semen was filled in straws (250 µL) and straws from each group were divided into two batches. One batch was processed for freezing and another batch was incubated at 4 °C for 4 h. The sperm kinematic and functional parameters were studied in both the batches. A significant (P < 0.05) positive effect of IGF1 was observed on functional membrane integrity (%) during incubation at 4 °C for 4 h in T3 as compared to control group. The spermatozoa (%) positive for structural membrane integrity, mitochondrial membrane potential and the metabolic activity in post-thaw semen were significantly (P < 0.05) high in T3 than the control group. The acrosomal integrity was significantly (P < 0.05) higher in T2 group as compared to control. The proteins (kDa) of 17.3 with pI 4.2 (calmodulin), 11.3 with pI 6.5 (dermcidin) and 18.1 with pI 5.5 (sperm acrosome membrane associated protein3) were protected in IGF1 group. The study suggests that IGF1 can be added to the extender for improving cryosurvial of buffalo spermatozoa.

The secrets of dermcidin action.

Antimicrobial peptides (AMPs) are important effector molecules of the innate immune defense of diverse species. The majority of known AMPs are cationic therefore facilitating the initial binding of the positively charged peptides to the negatively charged bacterial membrane. Dermcidin (DCD) is constitutively expressed in eccrine sweat glands, secreted into sweat and transported to the epidermal surface where it is proteolytically processed giving rise to several truncated DCD peptides. Its processed forms such as the anionic 48mer DCD-1L and the 47mer DCD-1 possess antimicrobial activity against numerous bacteria including Staphylococcus aureus. Here, the latest knowledge regarding the mode of action of the anionic DCD-1(L) and the functional consequences of their interaction with bacterial membranes is reviewed. There is evidence that the interaction of DCD-1(L) with negatively charged bacterial phospholipids leads to Zn(2+) dependent formation of oligomeric complexes in the bacterial membrane, which subsequently leads to ion channel formation resulting in membrane depolarization and bacterial cell death.

The microbiome-derived antibacterial lugdunin acts as a cation ionophore in synergy with host peptides.

Lugdunin is a microbiome-derived antibacterial agent with good activity against Gram-positive pathogens in vitro and in animal models of nose colonization and skin infection. We have previously shown that lugdunin depletes bacterial energy resources by dissipating the membrane potential of Staphylococcus aureus. Here, we explored the mechanism of action of lugdunin in more detail and show that lugdunin quickly depolarizes cytoplasmic membranes of different bacterial species and acidifies the cytoplasm of S. aureus within minutes due to protonophore activity. Varying the salt species and concentrations in buffers revealed that not only protons are transported, and we demonstrate the binding of the monovalent cations K+, Na+, and Li+ to lugdunin. By comparing known ionophores with various ion transport mechanisms, we conclude that the ion selectivity of lugdunin largely resembles that of 15-mer linear peptide gramicidin A. Direct interference with the main bacterial metabolic pathways including DNA, RNA, protein, and cell wall biosyntheses can be excluded. The previously observed synergism of lugdunin with dermcidin-derived peptides such as DCD-1 in killing S. aureus is mechanistically based on potentiated membrane depolarization. We also found that lugdunin was active against certain eukaryotic cells, however strongly depending on the cell line and growth conditions. While adherent lung epithelial cell lines were almost unaffected, more sensitive cells showed dissipation of the mitochondrial membrane potential. Lugdunin seems specifically adapted to its natural environment in the respiratory tract. The ionophore mechanism is refractory to resistance development and benefits from synergy with host-derived antimicrobial peptides. IMPORTANCE: The vast majority of antimicrobial peptides produced by members of the microbiome target the bacterial cell envelope by many different mechanisms. These compounds and their producers have evolved side-by-side with their host and were constantly challenged by the host's immune system. These molecules are optimized to be well tolerated at their physiological site of production, and their modes of action have proven efficient in vivo. Imbalancing the cellular ion homeostasis is a prominent mechanism among antibacterial natural products. For instance, over 120 naturally occurring polyether ionophores are known to date, and antimicrobial peptides with ionophore activity have also been detected in microbiomes. In this study, we elucidated the mechanism underlying the membrane potential-dissipating activity of the thiazolidine-containing cycloheptapeptide lugdunin, the first member of the fibupeptides discovered in a commensal bacterium from the human nose, which is a promising future probiotic candidate that is not prone to resistance development.

In vivo imaging of patients with chronic pruritus of unknown origin reveals partial sweat duct obstruction with partial itch resolution upon retinoid treatment.

Background: Chronic pruritus of unknown origin (CPUO) is poorly understood and lacks effective treatment options. Objectives: We aimed to elucidate abnormalities in the sweat apparatus of patients with CPUO, and to assess efficacy and safety of treatment with systemic retinoids. Methods: An initial case-control study included 20 affected patients and five healthy controls, for whom heat and sweating were induced, either through a standardized exercise protocol or ingestion of hot water. In vivo high-definition optical coherence tomography, whole-body starch-iodine testing, and skin biopsy for immunofluorescence staining were done to evaluate for sweat duct obstruction. A subsequent retrospective cohort analysis included 56 patients with CPUO, seen at an Itch subspecialty clinic of a single tertiary referral centre, who failed conventional treatments and were treated with isotretinoin and/or acitretin from May 2014 to November 2020. Treatment response to retinoids was defined as a sustained reduction in itch score of ≥2/10. Safety was assessed by proportion stopping treatment due to side effects. Results: In vivo imaging in 19 (95%) patients revealed features of partial keratinaceous sweat duct obstruction with statistically significant luminal dilatation compared to controls. Immunofluorescence studies of three patients' paired lesional/non-lesional biopsies revealed dermcidin accumulation within sweat glands coupled with dermcidin leakage in itchy skin. Fifty-six patients (mean [SD] age 55.2 [17.5] years, 69.6% male) were treated with systemic retinoids. Mean (SD) duration of itch was 116.3 (140.4) months and mean (SD) itch score was 8.2 (1.8). Forty-one (73.2%) initially received isotretinoin, and 15 (26.8%) acitretin. At three months, mean itch score reduced by 2.38 (95% CI -3.2 to -1.6, p < 0.0001). Thirty-eight (67.9%) had a sustained response. Eight (14.81%) achieved an itch score of 0 or 1, with four stopping treatment for a mean (SD) of 318.5 (291.2) days without relapse. Eight (14.3%) stopped or switched retinoid due to adverse effects, with similar incidences between both retinoids, the commonest being dryness. Conclusion: Based on novel findings from physiological imaging studies identifying partial keratinaceous sweat duct obstruction in CPUO, we instituted systemic retinoid treatment to address the underlying pathology. In patients who failed conventional therapies, the treatment appears effective and safe.

Focal hypohidrosis in lesional skin in a probable case of confluent and reticulated papillomatosis: A case report with insight into the pathomechanism of recurrence.

Confluent and reticulated papillomatosis (CRP) is a rare skin disorder that develops in young adults and presents as persistent brown papules and plaques predominantly affecting the intertriginous areas, however, its etiopathogenesis remains elusive. Herein, we report a probable case of CRP with lesional hypohidrosis as detected by sweat test and provide insight into the pathomechanism. A 23-year-old man presented with nine-months history of painful sensation on his trunk without any skin change. The result of sweat test was compatible with acquired idiopathic generalized anhidrosis. Topical heparinoid and physical exercise improved the symptoms. However, he started to notice asymptomatic brownish reticulated macules on the trunk. Intriguingly, focal hypohidrosis, as detected by sweat test was evident on the macules. In histology, the lesional skin demonstrated hyperkeratosis, acanthosis, basal melanosis, mild papillomatosis, and obstruction of the sweat duct in the upper dermis, which were not observed in the peri-lesional skin. Accumulation of the sweat in the luminal aspect of the secretory portion and dilation of the sweat duct in the deeper dermis was detected in the lesional skin, as highlighted by anti-dermcidin staining. Aquaporin 5 expression in the secretory portion was more confined to the cell membrane in the lesional skin. Both brownish macules and lesional hypohidrosis simultaneously improved in summer and exacerbated in winter. Literature review found nine reports on recurrent CRP, and obesity was thought to be a major comorbidity in recurrent CRP cases. Obesity is often associated with sweat dysregulation. This, together with the findings in our case, implied the possible contribution of focal sweating abnormality in the pathogenesis of reticulated skin lesion in our case.

Dermcidin Enhances the Migration, Invasion, and Metastasis of Hepatocellular Carcinoma Cells In Vitro and In Vivo.

Background and Aims: Hepatocellular carcinoma (HCC) is a common primary liver neoplasm with high mortality. Dermcidin (DCD), an antimicrobial peptide, has been reported to participate in oncogenesis. This study assessed the effects and underlying molecular events of DCD overexpression and knockdown on the regulation of HCC progression in vitro and in vivo. Methods: The serum DCD level was detected using enzyme-linked immunosorbent assay. DCD overexpression, knockdown, and Ras-related C3 botulinum toxin substrate 1 (Rac1) rescue were performed in SK-HEP-1 cells using plasmids. Immunofluorescence staining, quantitative PCR, and Western blotting were used to detect the expression of different genes and proteins. Differences in HCC cell migration and invasion were detected by Transwell migration and invasion assays. A nude mouse HCC cell orthotopic model was employed to verify the in vitro data. Results: The level of serum DCD was higher in patients with HCC and in SK-HEP-1 cells. DCD overexpression caused upregulation of DCD, fibronectin, Rac1, and cell division control protein 42 homologue (Cdc42) mRNA and proteins as well as actin-related protein 2/3 (Arp2/3) protein (but reduced Arp2/3 mRNA levels) and activated Rac1 and Cdc42. Phenotypically, DCD overexpression induced HCC cell migration and invasion in vitro, whereas knockout of DCD expression had the opposite effects. A Rac1 rescue experiment in DCD-knockdown HCC cells increased HCC cell migration and invasion and increased the levels of active Rac1/total Rac1, Wiskott-Aldrich syndrome family protein (WASP), Arp2/3, and fibronectin. DCD overexpression induced HCC cell metastasis to the abdomen and liver in vivo. Conclusions: DCD promotes HCC cell migration, invasion, and metastasis through upregulation of noncatalytic region of tyrosine kinase adaptor protein 1 (Nck1), Rac1, Cdc42, WASP, and Arp2/3, which induce actin cytoskeletal remodeling and fibronectin-mediated cell adhesion in HCC cells.

A rare loss-of-function genetic mutation suggest a role of dermcidin deficiency in hidradenitis suppurativa pathogenesis.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a multifactorial aetiology that involves a strict interplay between genetic factors, immune dysregulation and lifestyle. Familial forms represent around 40% of total HS cases and show an autosomal dominant mode of inheritance of the disease. In this study, we conducted a whole-exome sequence analysis on an Italian family of 4 members encompassing a vertical transmission of HS. Focusing on rare damaging variants, we identified a rare insertion of one nucleotide (c.225dupA:p.A76Sfs*21) in the DCD gene encoding for the antimicrobial peptide dermcidin (DCD) that was shared by the proband, his affected father and his 11-years old daughter. Since several transcriptome studies have shown a significantly decreased expression of DCD in HS skin, we hypothesised that the identified frameshift insertion was a loss-of-function mutation that might be associated with HS susceptibility in this family. We thus confirmed by mass spectrometry that DCD levels were diminished in the affected members and showed that the antimicrobial activity of a synthetic DCD peptide resulting from the frameshift mutation was impaired. In order to define the consequences related to a decrease in DCD activity, skin microbiome analyses of different body sites were performed by comparing DCD mutant and wild type samples, and results highlighted significant differences between the groins of mutated and wild type groups. Starting from genetic analysis conducted on an HS family, our findings showed, confirming previous transcriptome results, the potential role of the antimicrobial DCD peptide as an actor playing a crucial part in the etio-pathogenesis of HS and in the maintenance of the skin's physiological microbiome composition; so, we can hypothesise that DCD could be used as a novel target for personalised therapeutic approach.

Dermcidin-derived polypeptides: DCD(86-103) induced inflammatory reaction in the skin by activation of mast cells via ST2.

BACKGROUND: Psoriasis is a chronic inflammatory disease. Mast cells are significantly increased and activated in the lesions of patients with psoriasis, contributing to psoriatic inflammation. Dermcidin (DCD) is a natural antibacterial peptide secreted by sweat glands and is usually transported to the epidermal surface by sweat. Whether DCD is involved in mast cell activation remains unclear and the mechanisms by which DCD is involved in skin inflammatory reactions require further investigation. METHODS: We investigated whether dermcidin-derived polypeptides DCD(86-103) activate mast cells and induce skin inflammatory reactions that contribute to psoriasis. Wild-type mice were treated with DCD(86-103) to observe the inflammatory reactions in the skin and cytokine release in vivo. The release of inflammatory mediators by mouse primary mast cells and LAD2 cells was measured in vitro. Molecular docking analysis, molecular dynamics simulation, and siRNA transfection were used to identify DCD(86-103). RESULTS: DCD(86-103) caused a skin inflammatory reaction in wild-type mice via cytokine release. Moreover, DCD(86-103) directly activated mast cells and induced cytokine release in vitro. ST2 may be a key receptor that mediates the activation effect of DCD(86-103) on mast cells leading to cytokine release. CONCLUSION: DCD(86-103) may have induced an inflammatory reaction and participated in the occurrence and development of psoriasis.

Expression of antimicrobial host defence peptides in the central nervous system during health and disease.

Antimicrobial host defence peptides (HDP) are critical for the first line of defence against bacterial, viral, and fungal pathogens. Over the past decade we have become more aware that, in addition to their antimicrobial roles, they also possess the potent immunomodulatory capacity. This includes chemoattracting immune cells, activating dendritic cells and macrophages, and altering T-cell differentiation. Most examinations of their immunomodulatory roles have focused on tissues in which they are very abundant, such as the intestine and the inflamed skin. However, HDP have now been detected in the brain and the spinal cord during a number of conditions. We propose that their presence in the central nervous system (CNS) during homeostasis, infection, and neurodegenerative disease has the potential to contribute to immunosurveillance, alter host responses and skew developing immunity. Here, we review the evidence for HDP expression and function in the CNS in health and disease. We describe how a wide range of HDP are expressed in the CNS of humans, rodents, birds, and fish, suggesting a conserved role in protecting the brain from pathogens, with evidence of production by resident CNS cells. We highlight differences in methodology used and how this may have resulted in the immunomodulatory roles of HDP being overlooked. Finally, we discuss what HDP expression may mean for CNS immune responses.

Association Between Dermcidin, Salusin-α, Salusin-ß Molecules and Diabetic Foot Infections.

Dermcidin, salusin-α, and salusin-ß are three recently discovered molecules that confer antimicrobial properties. The present study aims to investigate the association between dermcidin, salusin-α, and salusin-ß in the etiopathology of patients with diabetic foot infection. The study included three groups: Group 1 - diabetic foot infection; Group 2 - diabetes without history of diabetic foot; and Group 3 - the control group. Plasma dermcidin, salusin-α, and salusin-ß levels were compared across the groups. Median (Q1-Q3) values of plasma dermcidin levels in Groups 1, 2, and 3 were 3.45 (0.8-4.4), 5.2 (3.7-6.4), and 5.8 (3.1-10) ng/mL, respectively. Diabetic foot infection group had significantly lower plasma dermcidin levels compared to diabetes only group and control group (P = .000, ANOVA), whereas there was no statistically significant difference between the Group 2 and Group 3 (P = .163, ANOVA). Salusin-α and salusin-ß levels were significantly higher in the Group 3 compared to the other groups. Based on our findings, diabetic foot infection group had significantly lower plasma dermcidin levels and salusin-α and salusin-ß levels were significantly higher in the control group. These molecules (dermcidin specifically) can be researched as an adjuvant therapeutic agent in addition to conventional treatments in diabetic foot diabetic foot infections. Also, it can be searched this may prevent many complications including amputation.

Human Dermcidin Protects Mice Against Hepatic Ischemia-Reperfusion-Induced Local and Remote Inflammatory Injury.

Background: Hepatic ischemia and reperfusion (I/R) injury is commonly associated with surgical liver resection or transplantation, and represents a major cause of liver damage and graft failure. Currently, there are no effective therapies to prevent hepatic I/R injury other than ischemic preconditioning and some preventative strategies. Previously, we have revealed the anti-inflammatory activity of a sweat gland-derived peptide, dermcidin (DCD), in macrophage/monocyte cultures. Here, we sought to explore its therapeutic potential and protective mechanisms in a murine model of hepatic I/R. Methods: Male C57BL/6 mice were subjected to hepatic ischemia by clamping the hepatic artery and portal vein for 60 min, which was then removed to initiate reperfusion. At the beginning of reperfusion, 0.2 ml saline control or solution of DCD (0.5 mg/kg BW) or DCD-C34S analog (0.25 or 0.5 mg/kg BW) containing a Cys (C)→Ser (S) substitution at residue 34 was injected via the internal jugular vein. For survival experiments, mice were subjected to additional resection to remove non-ischemic liver lobes, and animal survival was monitored for 10 days. For mechanistic studies, blood and tissue samples were collected at 24 h after the onset of reperfusion, and subjected to measurements of various markers of inflammation and tissue injury by real-time RT-PCR, immunoassays, and histological analysis. Results: Recombinant DCD or DCD-C34S analog conferred a significant protection against lethal hepatic I/R when given intravenously at the beginning of reperfusion. This protection was associated with a significant reduction in hepatic injury, neutrophilic CXC chemokine (Mip-2) expression, neutrophil infiltration, and associated inflammation. Furthermore, the administration of DCD also resulted in a significant attenuation of remote lung inflammatory injury. Mechanistically, DCD interacted with epidermal growth factor receptor (EGFR), a key regulator of liver inflammation, and significantly inhibited hepatic I/R-induced phosphorylation of EGFR as well as a downstream signaling molecule, protein kinase B (AKT). The suppression of EGFR expression by transducing Egfr-specific shRNA plasmid into macrophages abrogated the DCD-mediated inhibition of nitric oxide (NO) production induced by a damage-associated molecular pattern (DAMP), cold-inducible RNA-binding protein, CIRP. Conclusions: The present study suggests that human DCD and its analog may be developed as novel therapeutics to attenuate hepatic I/R-induced inflammatory injury possibly by impairing EGFR signaling.