Cutaneous Inflammatory Responses Research Articles

Nuclear versus cytoplasmic IKKα signaling in keratinocytes leads to opposite skin phenotypes and inflammatory responses, and a different predisposition to cancer.

IKKα is known as an essential protein for skin homeostasis. However, the lack of suitable models to investigate its functions in the skin has led to IKKα being mistakenly considered as a suppressor of non-melanoma skin cancer (NMSC) development. In this study, using our previously generated transgenic mouse models expressing exogenous IKKα in the cytoplasm (C-IKKα mice) or in the nucleus (N-IKKα mice) of basal keratinocytes, we demonstrate that at each subcellular localization, IKKα differently regulates signaling pathways important for maintaining the balance between keratinocyte proliferation and differentiation, and for the cutaneous inflammatory response. In addition, each type of IKKα-transgenic mice shows different predisposition to the development of spontaneous NMSC. Specifically, N-IKKα mice display an atrophic epidermis with exacerbated terminal differentiation, signs of premature skin aging, premalignant lesions, and develop squamous cell carcinomas (SCCs). Conversely, C-IKKα mice, whose keratinocytes are nearly devoid of endogenous nuclear IKKα, do not develop skin SCCs, although they exhibit hyperplastic skin with deficiencies in terminal epidermal differentiation, chronic cutaneous inflammation, and constitutive activation of STAT-3 and NF-κB signaling pathways. Altogether, our data demonstrate that alterations in the localization of IKKα in the nucleus or cytoplasm of keratinocytes cause opposite skin changes and differentially predispose to the growth of skin SCCs.

Pilonidal granuloma formation after an incision and drainage procedure is associated with retained hair within the sinus – A case series

Introduction and importancePilonidal disease may present with a draining secondary sinus or granuloma, but the development of these findings is not well-characterized. Case presentationTwo adolescent males presented with pilonidal disease. The first patient had a gluteal cleft abscess, and an incision and drainage procedure was performed. Although the abscess resolved, the incision site formed a granuloma with intermittent draining wound with granulation tissue. He underwent a pit-picking procedure along with excision of the granuloma. A large amount of hair was also removed from within the pilonidal sinus. The second patient underwent an incision and drainage procedure to treat the pilonidal abscess. The incision site evolved into a granuloma with recurring drainage. A pit-picking procedure was performed, and the granuloma was excised. During the excision, a moderate amount of hair was evacuated from the pilonidal sinus. Clinical discussionMany pilonidal patients present with a granuloma or secondary sinus at the gluteal cleft, but there has been no documentation of the natural history of this development. The role of hair is central to pilonidal disease pathophysiology and is a known factor in foreign body granuloma formation – a cutaneous inflammatory response to endogenous or exogenous material in the dermis that is not broken down readily by macrophages. ConclusionEven though the pilonidal abscess was drained with an incision, a granuloma was able to form with recurrent drainage when hair was retained within the pilonidal sinus.

Alternative autophagy dampens UVB-induced NLRP3 inflammasome activation in human keratinocytes

Sunlight exposure results in an inflammatory reaction of the skin commonly known as sunburn, which increases skin cancer risk. In particular, the ultraviolet B (UVB) component of sunlight induces inflammasome activation in keratinocytes to instigate the cutaneous inflammatory responses. Here, we explore the intracellular machinery that maintains skin homeostasis by suppressing UVB-induced inflammasome activation in human keratinocytes. We found that pharmacological inhibition of autophagy promoted UVB-induced NLRP3 inflammasome activation. Unexpectedly, however, gene silencing of Atg5 or Atg7, which are critical for conventional autophagy, had no effect, whereas gene silencing of Beclin1, which is essential not only for conventional autophagy but also for Atg5/Atg7-independent alternative autophagy, promoted UVB-induced inflammasome activation, indicating an involvement of alternative autophagy. We found that damaged mitochondria were highly accumulated in UVB-irradiated keratinocytes when alternative autophagy was inhibited, and they appear to be recognized by NLRP3. Overall, our findings indicate that alternative autophagy, rather than conventional autophagy, suppresses UVB-induced NLRP3 inflammasome activation through the clearance of damaged mitochondria in human keratinocytes, and illustrate a previously unknown involvement of alternative autophagy in inflammation. Alternative autophagy may be a new therapeutic target for sunburn and associated cutaneous disorders.

Sexual dimorphism in melanocyte stem cell behavior reveals combinational therapeutic strategies for cutaneous repigmentation

Vitiligo is an autoimmune skin disease caused by cutaneous melanocyte loss. Although phototherapy and T cell suppression therapy have been widely used to induce epidermal re-pigmentation, full pigmentation recovery is rarely achieved due to our poor understanding of the cellular and molecular mechanisms governing this process. Here, we identify unique melanocyte stem cell (McSC) epidermal migration rates between male and female mice, which is due to sexually dimorphic cutaneous inflammatory responses generated by ultra-violet B exposure. Using genetically engineered mouse models, and unbiased bulk and single-cell mRNA sequencing approaches, we determine that manipulating the inflammatory response through cyclooxygenase and its downstream prostaglandin product regulates McSC proliferation and epidermal migration in response to UVB exposure. Furthermore, we demonstrate that a combinational therapy that manipulates both macrophages and T cells (or innate and adaptive immunity) significantly promotes epidermal melanocyte re-population. With these findings, we propose a novel therapeutic strategy for repigmentation in patients with depigmentation conditions such as vitiligo.

Microplastics in dermatology: Potential effects on skin homeostasis.

Microplastics (MPs) and nanoplastics (NPs) have become a growing concern in dermatology due to their widespread presence in cosmetic formulations and the environment. These minuscule synthetic polymer particles prompt an essential exploration of their potential impact on dermatological homeostasis. This study aims to investigate the effects of MPs and NPs on the integumentary system. Specifically, it seeks to understand the potential cutaneous alterations, inflammatory responses, and disruptions to the skin's physiological functions caused by these synthetic particles. The investigation involves a comprehensive analysis of emerging research on MPs and NPs. This includes their presence in cosmetic formulations and environmental pervasiveness. The study delves into their capacity to breach the cutaneous barrier, raising concerns about the implications of prolonged exposure. Evidence suggests that MPs and NPs may indeed incite cutaneous alterations, provoke inflammatory responses, and disturb the homeostasis of the skin's physiological functions. Their small dimensions enhance their capability to breach the cutaneous barrier, further emphasizing the apprehensions associated with prolonged exposure. While a precise understanding of the implications of MPs and NPs on dermatological health remains an ongoing scientific endeavor, this study underscores the growing significance of these synthetic particles. The findings emphasize the need for proactive measures to safeguard both individual well-being and environmental preservation in the context of dermatological health.

Anti-Inflammatory Artificial Extracellular Vesicles with Notable Inhibition of Particulate Matter-Induced Skin Inflammation and Barrier Function Impairment.

Particulate matter (PM) exposure disrupts the skin barrier, causing cutaneous inflammation that may eventually contribute to the development of various skin diseases. Herein, we introduce anti-inflammatory artificial extracellular vesicles (AEVs) fabricated through cell extrusion using the biosurfactant PEGylated mannosylerythritol lipid (P-MEL), hereafter named AEVP-MEL. The P-MEL has anti-inflammatory abilities with demonstrated efficacy in inhibiting the secretion of pro-inflammatory mediators. Mechanistically, AEVP-MEL enhanced anti-inflammatory response by inhibiting the mitogen-activated protein kinase (MAPK) pathway and decreasing the release of inflammatory mediators such as reactive oxygen species (ROS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines in human keratinocytes. Moreover, AEVP-MEL promoted increased expression levels of skin barrier proteins (e.g., involucrin, IVL) and water-proteins (e.g., aquaporin 3, AQP3). In vivo studies revealed that repeated PM exposure to intact skin resulted in cutaneous inflammatory responses, including increased skin thickness (hyperkeratosis) and mast cell infiltration. Importantly, our data showed that the AEVP-MEL treatment significantly restored immune homeostasis in the skin affected by PM-induced inflammation and enhanced the intrinsic skin barrier function. This study highlights the potential of the AEVP-MEL in promoting skin health against PM exposure and its promising implications for the prevention and treatment of PM-related skin disorders.

HSP90, a Common Therapeutic Target for Suppressing Skin Injury Caused by Exposure to Chemically Diverse Classes of Blistering Agents.

Vesicants such as arsenicals and mustards produce highly painful cutaneous inflammatory and blistering responses, hence developed as chemical weapons during World War I/II. Here, using lewisite and sulfur mustard surrogates, namely phenylarsine oxide (PAO) and 2-chloroethyl ethyl sulfide (CEES), respectively, we defined a common underlying mechanism of toxic action by these two distinct classes of vesicants. Murine skin exposure to these chemicals causes tissue destruction characterized by increase in skin bifold thickness, Draize score, infiltration of inflammatory cells, and apoptosis of epidermal and dermal cells. RNA sequencing analysis identified ∼346 inflammatory genes that were commonly altered by both PAO and CEES, along with the identification of cytokine signaling activation as the top canonical pathway. Activation of several proinflammatory genes and pathways is associated with phosphorylation-dependent activation of heat shock protein 90α (p-HSP90α). Topical treatment with known HSP90 inhibitors SNX-5422 and IPI-504 post PAO or CEES skin challenge significantly attenuated skin damage including reduction in overall skin injury and clinical scores. In addition, highly upregulated inflammatory genes Saa3, Cxcl1, Ccl7, IL-6, Nlrp3, Csf3, Chil3, etc. by both PAO and CEES were significantly diminished by treatment with HSP90 inhibitors. These drugs not only reduced PAO- or CEES-induced p-HSP90α expression but also its client proteins NLRP3 and pP38 and the expression of their target inflammatory genes. Our data confirm a critical role of HSP90 as a shared underlying molecular target of toxicity by these two distinct vesicants and provide an effective and novel medical countermeasure to suppress vesicant-induced skin injury. SIGNIFICANCE STATEMENT: Development of effective and novel mechanism-based antidotes that can simultaneously block cutaneous toxic manifestations of distinct vesicants is important and urgently needed. Due to difficulties in determining the exact nature of onsite chemical exposure, a potent drug that can suppress widespread cutaneous damage may find great utility. Thus, this study identified HSP90 as a common molecular regulator of cutaneous inflammation and injury by two distinct warfare vesicants, arsenicals and mustards, and HSP90 inhibitors afford significant protection against skin damage.

Early cutaneous inflammatory response at different degree of burn and its significance for clinical diagnosis and management

A complete characterization of the burn wound based on cutaneous architectural changes and inflammatory response is extremely important to provide evidence for progressive changes in the burn wound. Burn wounds are highly susceptible to conversion into deeper wounds, which need special care and attention; thereby, the complete characterization of burn wound type and their subsequent inflammatory status in the cutaneous system at the earliest is of paramount importance. Inflammatory markers at different degrees will help clinicians devise better and more specific treatment strategies for each burn type.The present study is carried out to profile pro-inflammatory gene expression along with immune cell quantification, vascular perfusion, and histopathological assessment in the cutaneous system of murine models. The study revealed that burn injury caused an immediate increase in vascular perfusion in superficial and partial-thickness burns, whereas there was a decrease in vascular perfusion in full-thickness burns. An influx of lymphocytes at the edges of burn wounds in each type of burn injury was well-orchestrated with the event of vascular perfusion. Further, pro-inflammatory gene expression profiling revealed significant upregulation vis-à-vis upregulation of TNF-α and MCP-1 genes, with an increase in the number of neutrophils following 72 h of injury that evidently cemented the conversion of superficial burn into partial-thickness burn. The molecular findings were profoundly supported by the histopathological changes.Thus, our foundational studies show distinct characteristic cutaneous changes correlated with the expression of key pro-inflammatory genes in three different types of burn injuries. Characterization of these cutaneous inflammatory responses provides a promising future for medical interventions involved with different degrees of burn injury, and it will also help in the pre-clinical testing of therapies for burn injury.

Psychological (co)morbidity in patients with psoriasis: the impact of pruritus and anogenital involvement on symptoms of depression and anxiety and on body dysmorphic concerns – a cross-sectional study

ObjectivesWhile stress plays a paramount role on the onset/exacerbation of psoriasis, via overactivation of the hypothalamic–pituitary–adrenal axis and increased release of pro-inflammatory cytokines, cutaneous inflammatory response induces, in turn, anxiety/depression...

Ubiquitination as a key regulatory mechanism for O3-induced cutaneous redox inflammasome activation

NLRP1 is one of the major inflammasomes modulating the cutaneous inflammatory responses and therefore linked to a variety of cutaneous conditions. Although NLRP1 has been the first inflammasome to be discovered, only in the past years a significant progress was achieved in understanding the molecular mechanism and the stimuli behind its activation. In the past decades a crescent number of studies have highlighted the role of air pollutants as Particulate Matter (PM), Cigarette Smoke (CS) and Ozone (O3) as trigger stimuli for inflammasomes activation, especially via Reactive Oxygen Species (ROS) mediators. However, whether NLRP1 can be modulated by air pollutants via oxidative stress and the mechanism behind its activation is still poorly understood. Here we report for the first time that O3, one of the most toxic pollutants, activates the NLRP1 inflammasome in human keratinocytes via oxidative stress mediators as hydrogen peroxide (H2O2) and 4-hydroxy-nonenal (4HNE). Our data suggest that NLRP1 represents a target protein for 4HNE adduction that possibly leads to its proteasomal degradation and activation via the possible involvement of E3 ubiquitin ligase UBR2. Of note, Catalase (Cat) treatment prevented inflammasome assemble and inflammatory cytokines release as well as NLRP1 ubiquitination in human keratinocytes upon O3 exposure.The present work is a mechanistic study that follows our previous work where we have showed the ability of O3 to induce cutaneous inflammasome activation in humans exposed to this pollutant. In conclusion, our results suggest that O3 triggers the cutaneous NLRP1 inflammasome activation by ubiquitination and redox mechanism.

Anti-Inflammatory and Anti-Acne Effects of Hamamelis virginiana Bark in Human Keratinocytes.

Cutibacterium acnes (C. acnes) is recognized as one of the main triggers of the cutaneous inflammatory response in acne vulgaris, a chronic skin disorder with a multifactorial origin. Witch hazel (Hamamelis virginiana L.) is a plant widely used for skin inflammatory conditions, with some preliminary anti-inflammatory evidence on the skin, but lacking data on acne conditions. This study aimed to evaluate the effect of a glycolic extract from Hamamelis virginiana bark (HVE) versus C. acnes-induced inflammation in human keratinocytes (HaCaT). Phytochemical investigations of HVE identified hamamelitannin (HT) and proanthocyanidins as the most abundant compounds (respectively, 0.29% and 0.30% w/wextract). HVE inhibited C. acnes-induced IL-6 release (IC50: 136.90 μg/mL), by partially impairing NF-κB activation; however, no antibacterial or antibiofilm activities were found. In addition, HVE showed greater anti-inflammatory activity when TNF-α was used as a proinflammatory stimulus (IC50 of 38.93 μg/mL for IL-8 release), partially acting by antioxidant mechanisms, as shown for VEGF inhibition. The effects of HVE are primarily based on the proanthocyanidin content, as HT was found inactive on all the parameters tested. These results suggest further investigations of HVE in other inflammatory-based skin diseases.

Evaluation of cutaneous and circulating (serum and exosomes) levels of chemokines (CCL17, CCL22, CCL27 and CCL28) in atopic dogs and their correlation with severity of the disease.

Canine atopic dermatitis (AD) is a complex multifactorial disease characterised by an exaggerated immunological response. Little is known about the role that cutaneous and circulating chemokines play in disease severity. To evaluate the messenger (m)RNA and protein levels of selected chemokines in skin and serum of healthy and atopic dogs, and in the atopic group to determine whether there is a correlation with disease severity. Skin biopsies and blood samples were taken from 12 privately owned atopic [lesional (AD-L) and nonlesional (AD-NL) skin] and 12 privately owned healthy dogs. Circulating exosomes were extracted from the serum. Cutaneous and exosomal mRNA levels of CCL17, CCL22, CCL27 and CCL28 were quantified using quantitative real-time PCR. Protein levels were evaluated using canine-specific ELISA kits. The severity and extent of the clinical signs also were assessed in the atopic dogs using Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) and a validated pruritus Visual Analog Scale (pVAS). The expression of CCL28 exosomes in skin was greater in AD-L when compared to healthy (P = 0.019) and AD-NL (P = 0.002) samples. However, serum expression was lower in dogs with AD compared to healthy dogs (P = 0.03). A higher expression of CCL17 and CCL22 was seen in AD-L when compared to healthy skin (P = 0.018 and P = 0.019, respectively). There also was a positive correlation between clinical scores and CCL22 (AD-NL; r = 0.6, P = 0.05) and between the pruritus score and CCL22 (AD-L; r = 0.6, P = 0.05). Differences in CCL27 concentrations were not observed. This study suggests that CCL17, CCL22 and CCL28 may play a role in the cutaneous inflammatory response in atopic dogs. They may be considered as markers of disease severity, although further studies are needed to validate these findings.

The protective effects of human milk components, 2′-fucosyllactose and osteopontin, against 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease with high morbidity in infants. Several bioactive components of human milk, such as 2′-fucosyllactose (2′-FL) and osteopontin (OPN), are reported to exhibit anti-inflammatory properties. This study determined that oral administration of 2′-FL and OPN significantly attenuated the 2,4-dinitrochlorobenzene (DNCB)-induced AD symptoms in BALB/c mice. 2′-FL and OPN treatment markedly downregulated the serum IgE level and decreased the numbers of mast cells and eosinophils in the dermal tissues from DNCB-sensitized mice. Interestingly, we found that the combination of OPN with 2′-FL produced a great therapeutic effect on AD in mice. Additionally, the result showed that the components suppressed Th2 response, resulting in an attenuated cutaneous inflammatory response. Furthermore, in vitro study validated that 2′-FL and OPN inhibited Th2 cells differentiation. Together, we conclude that 2′-FL and OPN ameliorates DNCB-induced AD-like skin inflammation, and its supplement might help to prevent AD in infants.

PI3Kδ Sustains Keratinocyte Hyperproliferation and Epithelial Inflammation: Implications for a Topically Druggable Target in Psoriasis.

The phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathway is aberrantly activated in psoriatic lesions and contributes to disease pathogenesis. Among PI3Ks enzymes, PI3Kα, β, and δ isoforms are known to bind the p85 regulatory subunit and mediate activation of AKT and other downstream effectors. In this study, we deepened our understanding of the expression and function of PI3Kδ in skin lesions of patients affected by psoriasis. For the first time, we found that PI3Kδ is overexpressed in psoriatic plaques, and its expression is not only confined to infiltrating immune cells but also accumulates in proliferating keratinocytes of the epidermal basal layer. We investigated the function of PI3Kδ in psoriatic skin by evaluating the impact of seletalisib, a newly developed selective PI3Kδ inhibitor, in both in vitro and in vivo experimental models of psoriasis. Of note, we found that PI3Kδ sustains keratinocyte hyperproliferation and impaired terminal differentiation induced by IL-22, as well as induces epithelial inflammation and resistance to apoptosis mediated by TNF-α in human keratinocytes. Mechanistically, PI3Kδ promotes PDK1 phosphorylation and signals through AKT-dependent or -independent pathways. It is worth mentioning that PI3Kδ inhibition by seletalisib attenuates the severity of psoriasiform phenotype induced in the Imiquimod-induced mouse model of psoriasis by restoring the physiological proliferation and differentiation programs in epidermal keratinocytes and contrasting the cutaneous inflammatory responses. Therefore, we suggest PI3Kδ as a potential topically druggable target in psoriasis and skin diseases characterized by epidermal hyperproliferation and skin inflammation.

Effects of Dietary Protein Intake on Cutaneous and Systemic Inflammation in Mice with Acute Experimental Psoriasis.

Background: Psoriasis is a systemic inflammatory disorder, primarily characterized by skin plaques. It is linked to co-morbidities including cardiovascular disease and metabolic syndrome. Several studies demonstrate that dietary habits can influence psoriasis development and severity. However, the effect of different dietary protein levels on psoriasis development and severity is poorly understood. In this study, we examine the influence of dietary protein on psoriasis-like skin disease in mice. Methods: We fed male C57BL/6J mice with regular, low protein and high protein chow for 4 weeks. Afterwards, we induced psoriasis-like skin disease by topical imiquimod (IMQ)-treatment on ear and back skin. The local cutaneous and systemic inflammatory response was investigated using flow cytometry analysis, histology and quantitative rt-PCR. Results: After 5 days of IMQ-treatment, both diets reduced bodyweight in mice, whereas only the high protein diet slightly aggravated IMQ-induced skin inflammation. IMQ-treatment induced infiltration of myeloid cells, neutrophils, and monocytes/macrophages into skin and spleen independently of diet. After IMQ-treatment, circulating neutrophils and reactive oxygen species were increased in mice on low and high protein diets. Conclusion: Different dietary protein levels had no striking effect on IMQ-induced psoriasis but aggravated the systemic pro-inflammatory phenotype.

Molecular characterization of four novel serpins in Psoroptes ovis var. cuniculi and their implications in the host-parasite interaction

Psoroptes ovis var. cuniculi infestation rapidly causes skin lesion, cutaneous inflammatory and subsequent adaptive immune response in rabbits. To success feeding and survive on the host skin, this mite should product bioactive molecules to confront host tissue repair and immune defense, but these molecules of this mite remains mostly unknown. Serpins have been proved to involve in diverse biological functions including parasite reproduction, survival and modulating host defense. Limited information is currently available on serpins from Psoroptes mites. Herein, we identified four novel serpins (PsoSP3-PsoSP6) in P. ovis var. cuniculi using bioinformatics and molecular biology techniques. Sequence analysis revealed that PsoSP3-PsoSP6 comprised the common features of typical serpins superfamily including serpin domains, signature or the reactive centre loop (RCL) domain. The recombinant PsoSP4-PsoSP6 (rPsoSP4-rPsoSP6) revealed variable potency inhibition on trypsin, chymotrypsin and elastase except for rPsoSP3 in inhibitory activity assays. By quantitative RT-PCR, the expressions of PsoSP3 and PsoSP4 were higher in juvenile mites (larva and nymph) than in adult mites, however, PsoSP5 and PsoSP6 appeared near-exclusive expression in adult female mites. Immunolocalization showed that native PsoSP4 protein was localized in uterus, whilst native PsoSP3, PsoSP5 and PsoSP6 were specifically localized in the ovarian nutritive cell (ONC) in ovary. Our findings indicated that PsoSP3-PsoSP6 might play critical roles in development and reproduction physiologies. rPsoSP4-rPsoSP6 might participate in modulating host inflammation, immune response and tissue repair.

Analysis of Systemic and Cutaneous Inflammatory Immune Response in Canine Atopic Dermatitis

Background: Canine atopic dermatitis (CAD) is a chronic and inflammatory disease present in veterinary dermatological practice. The inflammation in CAD is triggered by environmental allergens and skin microorganisms, which are responsible for the worsening of cutaneous lesions. This continuous activation of skin inflammatory process can induce the production of free radicals that also contribute to cellular damage and ultimately leads to changes in blood parameters in dogs with CAD. Although there are reports of inflammatory parameters in CAD, there are a lack of studies correlating skin lesions, blood leukocytes and oxidative stress. Based on that,this study aimed to evaluate the integumentary and systemic inflammatory response in dogs with atopic dermatitis. Materials, Methods & Results: Dogs with confirmed diagnosis of canine atopic dermatitis (n = 10) were divided in two groups according to CADESI-IV: AI, with CADESI between 0-10, AII, with CADESI between 10-34, and control group (n = 5). Blood-biochemical and histological analysis were performed to access systemic and cutaneous inflammatory response. AII group tended to higher neutrophil and eosinophil counts, as well as neutrophil/lymphocyte ratio (NLR) when compared to AI. The albumin was lower in AII compared to AI and control (P < 0.05), while total bilirubin and malondialdehyde (MDA) did not differ between groups. NLR (r = 0.64 and P = 0.04) and MDA (r = 0.54 and P = 0.1) were positively correlated with CADESI, while albumin was negatively correlated with CADESI (r = -0.79 and P = 0.005). Histopathological analysis revealed a larger number of neutrophils, macrophages and mast cells in AI and AII than in control group (P < 0.05). Discussion: In this study it was possible to evaluate the systemic and cutaneous leukocyte dynamics in CAD. Skin inflammation induces the production of chemotactic molecules contribute to neutrophil outflow from blood vessel toward the affected tissue, which can be visualized as perivascular inflammatory infiltrate and exocytosis. At systemic level, there was a tendency to increase in total leukocytes and circulating neutrophil count in group AII, as well as in neutrophil/lymphocyte ratio (NLR), when compared to AI. The NLR is a widely available and inexpensive laboratory biomarker that quantifies systemic inflammation, being used in human medicine to evaluate prognosis in different types of cancer. In our study, dogs in AII group showed an increased NLR compared to AI and control, which demonstrates the influence of skin injury in systemic parameters. Furthermore, AII group is composed of dogs with greater lesion state, which reflects in higher NLR values. Since this disease is known by its chronicity and may remain stable for years, NLR may be a novel biomarker to evaluate acute exacerbation in CAD and could potentially explain why some patients have longer crisis duration and frequent flares. The maintenance of the inflammatory state also induces the production of oxidizing substances, which possibly exceed the total antioxidant capacity, generating a situation of oxidative stress, which can result in damage to membrane lipids and release of their products. MDA is reliable and is the most commonly used marker of the overall lipid peroxidation level and the presence of oxidative stress. This result may be related with the antioxidant system, such as albumin and bilirubin, which was able to promote an efficient control of oxidant substances. In conclusion, the presented data demonstrated an inflammatory process progression as well as introduced NLR as a potential marker of disease exacerbation in CAD.

Tissue Damage in Human Cutaneous Leishmaniasis: Correlations Between Inflammatory Cells and Molecule Expression.

Cutaneous leishmaniasis (CL) is caused by the bite of the infected sand fly, which inoculates parasites of Leishmania spp and triggers an immune response. An exacerbated cutaneous inflammatory response is crucial for controlling parasite burden but can also promote tissue damage. This study aimed to characterize the populations of natural killer (NK), CD57+, CD4+, and CD8+ T cells, CD20+ B cells, as well as CD68+ macrophages, in biopsies of ulcerated CL lesions, and quantify the production of perforin+, grazyme B+, interleukin 1 beta (IL-1β+) and Tumor Necrosis Factor (TNF-α+ cells). We then correlated these parameters with necrosis, inflammation and the number of amastigotes. CD4+ T cells were positively correlated to the extent of inflammation, B cells and IL-1β+ were associated with the extent of necrosis, CD68+ macrophages and perforin were correlated with the number of amastigotes, and CD57+ NK cells was correlated to CD68+ macrophages and amastigotes. In sum, the finding suggests that the production of cytotoxic granules and cytokines by inflammatory cells contributes to tissue damage in CL lesions.

095 Single-cell Profiling Reveals a Highly Specific, Compartmentalized Functional Response in the Cutaneous Immune System

Effective inflammatory responses arise from coordinated reaction of diverse immune cell populations to exogenous stimuli. The considerable heterogeneity of these populations has impeded high-resolution dissection of their molecular behavior during activation. To systematically characterize cutaneous inflammatory response, we analyzed 52,086 immune cells isolated from mouse skin by single cell RNA sequencing (scRNA-seq), after induction of Toll-like receptor (TLR)-dependent inflammation using imiquimod (IMQ) or delayed-type hypersensitivity using oxazolone (OXA).

Sm16, A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host.

Sm16 is an immunomodulatory protein that seems to play a key role in the suppression of the cutaneous inflammatory response during Schistosoma mansoni penetration of the skin of definitive hosts. Therefore, Sm16 represents a potential target for protective immune responses induced by vaccination. In this work, we generated the recombinant protein rSm16 and produced polyclonal antibodies against this protein to evaluate its expression during different parasite life-cycle stages and its location on the surface of the parasite. In addition, we analyzed the immune responses elicited by immunization with rSm16 using two different vaccine formulations, as well as its ability to induce protection in Balb/c mice. In order to explore the biological function of Sm16 during the course of experimental infection, RNA interference was also employed. Our results demonstrated that Sm16 is expressed in cercaria and schistosomula and is located in the schistosomula surface. Despite humoral and cellular immune responses triggered by vaccination using rSm16 associated with either Freund's or alum adjuvants, immunized mice presented no reduction in either parasite burden or parasite egg laying. Knockdown of Sm16 gene expression in schistosomula resulted in decreased parasite size in vitro but had no effect on parasite survival or egg production in vivo. Thus, our findings demonstrate that although the vaccine formulations used in this study succeeded in activating immune responses, these failed to promote parasite elimination. Finally, we have shown that Sm16 is not vital for parasite survival in the definitive host and hence may not represent a suitable target for vaccine development.