Role of the NLRP1 inflammasome in skin cancer and inflammatory skin diseases.

Inflammasomes are cytoplasmic protein complexes that play a crucial role in protecting the host against pathogenic and sterile stressors by initiating inflammation. Upon activation, these complexes directly regulate the proteolytic processing and activation of proinflammatory cytokines interleukin (IL)-1ß and IL-18 to induce a potent inflammatory response, and induce a programmed form of cell death called pyroptosis to expose intracellular pathogens to the surveillance of the immune system, thus perpetuating inflammation. There are various types of inflammasome complexes, with the NLRP1 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-1) inflammasome being the first one identified and currently recognized as the predominant inflammasome sensor protein in human keratinocytes. Human NLRP1 exhibits a unique domain structure, containing both an N-terminal pyrin (PYD) domain and an effector C-terminal caspase recruitment domain (CARD). It can be activated by diverse stimuli, such as viruses, ultraviolet B radiation and ribotoxic stress responses. Specific mutations in NLRP1 or related genes have been associated with rare monogenic skin disorders, such as multiple self-healing palmoplantar carcinoma; familial keratosis lichenoides chronica; autoinflammation with arthritis and dyskeratosis; and dipeptidyl peptidase 9 deficiency. Recent research breakthroughs have also highlighted the involvement of dysfunctions in the NLRP1 pathway in a handful of seemingly unrelated dermatological conditions. These range from monogenic autoinflammatory diseases to polygenic autoimmune diseases such as vitiligo, psoriasis, atopic dermatitis and skin cancer, including squamous cell carcinoma, melanoma and Kaposi sarcoma. Additionally, emerging evidence implicates NLRP1 in systemic lupus erythematosus, pemphigus vulgaris, Addison disease, Papillon-Lefèvre syndrome and leprosy. The aim of this review is to shed light on the implications of pathological dysregulation of the NLRP1 inflammasome in skin diseases and investigate the potential rationale for targeting this pathway as a future therapeutic approach.

Short-, mid- and long-term efficacy of dupilumab in moderate to severe atopic dermatitis: a real life multicenter Italian study on 2576 patients.

BACKGROUND: The efficacy and safety of dupilumab in atopic dermatitis (AD) have been defined in clinical trials but limited real-world evidence on long term treatment outcomes are currently available to inform clinical decisions. OBJECTIVES: to describe long-term effectiveness and safety of dupilumab up to 48 months in patients with moderate-to-severe AD. METHODS: a multicenter, retrospective, dynamic cohort study was conducted to assess long term effectiveness and safety of dupilumab in patients with moderate to severe AD in a real-world setting. Predictors of minimal disease activity (MDA) optimal treatment target criteria (defined as the simultaneous achievement of EASI90, itch NRS score ≤1, sleep NRS score ≤1 and DLQI ≤1) were investigated. RESULTS: 2576 patients were enrolled from June 2018 to July 2022. MDA optimal treatment target criteria were achieved by 506 (21.91%), 769 (40.63%), 628 (50.36%), 330 (55.37%) and 58 (54.72%) of those that reached 4, 12, 24, 36 and 48 months of follow-up, respectively. Logistic regression revealed a negative effect on MDA achievement for conjunctivitis and food allergy at all timepoints. Adverse events (AE) were mild and were observed in 373 (15.78%), 166 (7.02%), 83 (6.43%), 27 (4.50%) and 5 (4.55%) of those that reached 4, 12, 24, 36 and 48 months of follow-up. Conjunctivitis was the most frequently reported AE during the available follow-up. AE led to treatment discontinuation in <1% of patients during the evaluated time periods. CONCLUSION: High long-term effectiveness and safety of dupilumab were confirmed in this dynamic cohort of patients with moderate to severe AD, regardless of clinical phenotype and course at baseline. Further research will be needed to investigate the effect of Th2 comorbidities and disease duration on the response to dupilumab and other newer therapeutics for AD.

Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1ß and IL-1R3 as possible therapeutic targets.

Sweet syndrome (SS) as a prototypic neutrophilic dermatosis (NDs) shares certain clinical and histologic features with monogenic auto-inflammatory disorders in which interleukin (IL)-1 cytokine family members play an important role. This has led to the proposal that NDs are polygenic auto-inflammatory diseases and has fuelled research to further understand the role of IL-1 family members in the pathogenesis of NDs. The aim of this study was to characterise the expression of the IL-1 family members IL-1ß, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1ß, IL-33, IL-36γ and their common co-receptor IL-1R3 was analysed by immunohistochemistry, in situ hybridisation and double immunofluorescence (IF) in healthy control skin (HC) and lesional skin samples of SS. Marked overexpression of IL-1ß in the dermis of SS (p < 0.001), and a non-significant increase in dermal (p = 0.087) and epidermal (p = 0.345) IL-36γ expression compared to HC was observed. Significantly increased IL-1R3 expression within the dermal infiltrate of SS skin samples (p = 0.02) was also observed, whereas no difference in IL-33 expression was found between SS and HC (p = 0.7139). In situ hybridisation revealed a good correlation between gene expression levels and the above protein expression levels. Double IF identifies neutrophils and macrophages as the predominant sources of IL-1ß. This study shows that IL-1ß produced by macrophages and neutrophils and IL-1R3 are significantly overexpressed in SS, thereby indicating a potential pathogenic role for this cytokine and receptor in SS.

Divergent in situ expression of IL-31 and IL-31RA between bullous pemphigoid and pemphigus vulgaris.

Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are two major autoimmune blistering skin diseases. Unlike PV, BP is accompanied by intense pruritus, suggesting possible involvement of the pruritogenic cytokine IL-31. However, the underlying mechanisms of the clinical difference between BP and PV in terms of pruritus are not fully understood. To compare the expression levels of IL-31 and its receptor IL-31RA in the lesional skin, including peripheral nerves in BP and PV patients, immunohistochemical staining for IL-31 and IL-31RA was performed in skin samples of BP and PV patients and healthy controls (HC). The IL-31RA-expressing area in epidermis and peripheral nerves was analysed using ImageJ and the percentage of positive cells for IL-31/IL-31RA in dermal infiltrating cells was manually quantified. Quantitative analyses revealed that IL-31/IL-31RA expressions in the epidermis and dermal infiltrate were significantly increased in BP compared to PV and HC. The difference between BP and PV became more obvious when advanced bullous lesions were compared. Peripheral nerves in BP lesions presented significantly higher IL-31RA expression compared to PV lesions. In conclusion, we found significantly augmented expressions of IL-31/IL-31RA in BP lesions, including peripheral nerves, in comparison to PV. These results suggest a possible contribution of IL-31/IL-31RA signalling to the difference between BP and PV in the facilitation of pruritus and local skin inflammation, raising the possibility of therapeutic targeting of the IL-31/IL-31RA pathway in BP patients.

Therapeutic potential of targeting interleukin-1 family cytokines in chronic inflammatory skin diseases.

The interleukin (IL)-1 family of cytokines is a central regulator of a myriad of immunological responses. It comprises several cytokines, including those belonging to the IL-1, IL-36 and IL-18 subfamilies, as well as IL-33. The IL-1 family primarily plays a role in orchestrating innate immune responses, but is also involved in adaptive immunity. Increased interest in the IL-1 family occurred following the discovery that dysregulation of IL-1 signalling underlies the pathogenesis of several monogenic autoinflammatory diseases, characterized by sterile inflammation involving the skin and other organs. This also provided increased understanding of the role of innate immunity and the IL-1 family in polygenic autoinflammatory skin conditions, such as neutrophilic dermatoses, as well as in some of the most common chronic inflammatory skin diseases, such as psoriasis and hidradenitis suppurativa. Several therapeutic agents have been developed to inhibit the IL-1 family members and their signalling pathways. These have shown therapeutic efficacy in several chronic inflammatory skin disorders. The aim of this review is to thoroughly describe the consequences of pathological dysregulation of the IL-1, IL-33, IL-36 and IL-18 pathways in dermatological conditions and to provide a forward-looking update on therapeutic strategies targeting signalling by IL-1 family cytokines.

Tildrakizumab in moderate-to-severe plaque psoriasis: A multicenter, retrospective, real-life study.

New biologic agents targeting interleukin (IL)23/T-helper17 axis, such as tildrakizumab, have been developed for the treatment of plaque psoriasis. To analyze the efficacy and safety of tildrakizumab in a real life setting of patients affected by moderate-to-severe psoriasis over a 28-week treatment period. A multicentric retrospective study was conducted in patients who initiated tildrakizumab between February 2020 and March 2021. Psoriasis Area and Severity Index-PASI was measured at baseline and after 4, 16 and 28 weeks. The percentage change in PASI value from baseline to the considered time-points, proportion of patients with absolute PASI <3 at week 28 and the percentages of achieving a PASI75 or PASI90 response were assessed. Data about potential safety issues and adverse events (AEs) were collected. Statistical analysis were performed for establish clinical efficacy and for variables predicting clinical response. Fifty nine patients with psoriasis were included. Overall mean PASI percentage reduction was of 88% from baseline to week 28 and 47 out of 59 patients (79.7%) at week 28 had an absolute PASI <3. PASI75 and PASI90 responses at week 28 were achieved by 48 (81.40%) patients and 38 (64.4.0%) patients, respectively. No substantial associations between gender, body mass index - BMI, PASI at baseline and prior exposition to biological therapies and the efficacy endpoints were retrieved. No serious safety issues or discontinuations related to adverse events were reported. In our real-life study, tildrakizumab showed high efficacy and a favorable safety profile, regardless of patient- and disease-related factors.

Therapeutic Impact and Management of Persistent Head and Neck Atopic Dermatitis in Dupilumab-Treated Patients.

BACKGROUND: Localization of atopic dermatitis (AD) in exposed areas such as the hands, head, and neck has been considered as a negative factor impacting on dupilumab response, although a comparison of exposed versus unexposed areas is not currently available. OBJECTIVES: The aim of this study is to evaluate the clinical response to dupilumab depending on the presence or persistency of AD skin manifestations in specific body areas. METHODS: The study retrospectively collected clinical and demographic data of adult patients affected by moderate to severe AD. Based on the anatomical sites involved, 5 subcohorts of patients were identified. RESULTS: A total of 41 patients were included in the study. Disease amelioration was detected during the study period, although baseline head/neck and hand localization was associated with a significantly lower likelihood of achieving an Eczema Area Severity Index (EASI) ≤1. In addition, patients with head/neck persistency showed a significantly lower response when compared to patients without persistency of head/neck AD in terms of both mean EASI and Dermatology Life Quality Index (DLQI) reduction. CONCLUSION: AD localization in exposed areas at the baseline and AD persistency at the head/neck may have a negative impact on certain treatment response parameters to dupilumab therapy.

Bullous pemphigoid in diabetic patients treated by gliptins: the other side of the coin.

Bullous pemphigoid (BP) is the most common autoimmune bullous skin disease that affects primarily patients older than 60 years. The majority of BP cases are spontaneous, but BP can also be triggered by certain drugs' exposures. Since 2011, a growing number of observations has been reporting cases of BP in Type 2 diabetic patients. These forms have been linked to the use of a new category of anti-diabetic drugs called dipeptidyl peptidase inhibitors (DPP-4i) or gliptins, but to date, the exact pathophysiological mechanisms underlying this association are not completely elucidated. Although conventional and gliptin-associated BP are thought to share similar clinical and histopathological features, our thorough review of the most recent literature, shows that these 2 forms are quite distinct: DPP-4-i-associated BP seems to appear at an earlier age than spontaneous BP, it may manifest either as a noninflammatory or inflammatory phenotype, while the conventional form presents with a typical inflammatory phenotype. Additionally, an important distinctive histological feature was recently shown in Gliptin-associated BP: these forms may present a less significant eosinophils infiltrate in the upper dermis of peri-blister lesions compared to the skin of patients with spontaneous BP, and this seems a specific feature of the clinically non-inflammatory forms. In accordance with previous literature, we found that the direct immunofluorescence (DIF) gives identical findings in both DPP-4i-associated and conventional forms of BP which is an IgG and complement C3 deposition as a linear band at the dermal-epidermal junction in perilesional skin. Indirect immunofluorescence shows the presence of IgG circulating autoantibodies in the patient's serum which titer does not differ between spontaneous and DPP-4i-associated BP, while the specificity of these autoantibodies, may be different in spontaneous, induced non-inflammatory and induced inflammatory forms, epitope spreading phenomenon seems to play a role in determining these specificities. Further research, based on integrated epidemiological, clinical, histo-immunological and pharmacogenomic approaches, may give more insight into these forms of BP. This combined approach will allow to better define BP endotypes and to unveil the mechanism of spontaneous or drug-induced breakage of the immunotolerance to skin self-antigens.

Risk of Skin Cancer in Patients with Psoriasis: Single-Center Retrospective Study Comparing Anti-TNFα and Phototherapy.

Background: The risk of developing non-melanoma skin cancers (NMSCs) in patients with psoriasis is highly debated, and, to date, there is no unambiguous consensus opinion. Psoriasis is known to be related to an increased likelihood of other comorbidities such as psoriatic arthritis, obesity, metabolic syndrome, depression, and cardiovascular disease. Regarding cancer risk, previous studies have reported a greater tendency for the development of cutaneous T-lymphomas and colon, breast, kidney, and lung cancers. Furthermore, data from network meta-analyses have shown that patients with psoriasis have a higher risk of developing squamous cell carcinomas (SCCs) and/or basal cell carcinomas (BCCs). Multiple factors may contribute to the development of NMSCs in psoriatic patients, ranging from immunosuppression induced by biologic agents to previous phototherapy. However, the extent to which each factor may impact this risk has not been entirely assessed. The aim of this study was to evaluate the risk of developing NMSCs in patients with psoriasis observed for at least 5 years, by directly comparing patients only treated with phototherapy and patients treated with anti-tumor necrosis factor α (TNFα) agents, naive to other systemic treatments or phototherapy. Methods: We conducted a single-center retrospective study at Siena University Hospital, Italy, on 200 adult patients with psoriasis divided into two groups: (i) group 1, including 100 patients treated with narrow-band UVB phototherapy (nb-UVB), and (ii) group 2, including 100 patients treated with anti-TNFα. The patients included in group 2 had to be naive to cDMARDs and biologics and treated with anti-TNFα continuously for 5 years without loss of efficacy. All patients were observed for 5 years and underwent annual dermatologic examinations to assess for the occurrence of BCC or SCC. Results: A total of 34 out of 100 patients treated with phototherapy had one BCC or one SCC and 10 out of 34 developed two skin cancers. In particular, five had both types (one BCC and one SCC), and five had two BCCs. Conclusions: The results of our study highlight how the risk of developing NMSCs is greater in patients undergoing phototherapy compared to those treated with anti-TNFα. It also draws attention to the consideration that patients with scalp psoriasis might need closer follow-up as they could be more at risk of developing NMSCs.

Therapeutic Potential of Targeting the JAK/STAT Pathway in Psoriasis: Focus on TYK2 Inhibition.

Psoriasis is an inflammatory skin disease with a chronic relapsing course and an often-detrimental impact on patients' quality of life. Thanks to incredible advances in research over the past few decades, the therapeutic armamentarium of psoriasis is now reasonably broad and structured, with several therapeutic agents that have demonstrated successful long-term control of this condition. However, there are still unfulfilled gaps resulting from the inherent limitations of existing therapies, which have paved the way for the identification of new therapeutic strategies or the improvement of existing ones. A great deal of attention has recently been paid to the JAK/STAT pathway, playing a crucial role in chronic inflammatory skin diseases, including psoriasis. Indeed, in a disease with such a complex pathogenesis, the possibility to antagonize multiple molecular pathways via JAK/STAT inhibition offers an undeniable therapeutic advantage. However, data from clinical trials evaluating the use of oral JAK inhibitors in immune-mediated disorders, such as RA, have arisen safety concerns, suggesting a potentially increased risk of class-specific AEs such as infections, venous thromboembolism, and malignancies. New molecules are currently under investigation for the treatment of psoriasis, such as deucravacitinib, an oral selective inhibitor that binds to the regulatory domain of TYK2, brepocitinib (PF-06700841) and PF-06826647 that bind to the active site in the catalytic domain. Due to the selective TYK2 blockade allowing the inhibition of key cytokine-mediated signals, such as those induced by IL-12 and IL-23, anti-TYK2 agents appear to be very promising as the safety profile seems to be superior compared with pan-JAK inhibitors. The aim of our review is to thoroughly explore the rationale behind the usage of JAK inhibitors in PsO, their efficacy and safety profiles, with a special focus on oral TYK2 inhibitors, as well as to provide a forward-looking update on novel therapeutic strategies targeting the TYK2 pathway in psoriasis.

Drug survival of biologics and non-biologics in patients affected by palmoplantar psoriasis: a "real-world", mono-center experience.

BACKGROUND: Data on the treatment of palmoplantar psoriasis (PP) are very limited as these patients are often excluded from clinical trials. Moreover, this form of psoriasis is often resistant to treatment, making its clinical management complex. METHODS: Primary endpoint was to evaluate the clinical and demographic characteristics and the drug survival of both biological and non-biological drugs in a population affected by PP. Secondary endpoint was to highlight any differences between the hyperkeratotic and pustular variant. We analyzed data from 233 psoriasis patients with palmoplantar involvement, with or without chronic plaque psoriasis. We performed a drug-survival analysis with the aid of Kaplan-Meier survival and a multivariate analysis to highlight the influence of certain variables on treatment persistence using a Cox regression model. RESULTS: The drug-survival analysis revealed that biologic drugs compared to non-biologic drugs are associated with a higher persistence in treatment (59.73 vs. 43.56%); in particular, anti-IL23 drugs were found to be the drugs with the best drug-survival overall (67.94% of patients at 60 months are still on these drugs). Furthermore, our multivariate analysis shows that when compared with biological drugs, non-biological drugs are associated with an increased risk of treatment discontinuation (HR = 1.95 [95% CI: 1.41-2.68], P = 0.001). CONCLUSIONS: Our study confirms the difficulty of treating PP and shows that biologic drugs are associated with longer persistence in treatment than non-biologics in both PP's variants, not because of their higher effectiveness but because of their better safety profile.

Therapeutic Potential of IL-1 Antagonism in Hidradenitis Suppurativa.

The immunopathogenesis of HS is partially understood and exhibits features of an autoinflammatory disease; it is associated with the potential involvement of B cells and the contribution of Th1 or Th17 cell subsets. Recently, the pathogenic role of both innate immunity and IL-1 family cytokines in HS has been deeply investigated. Several agents targeting the IL-1 family pathway at different levels are currently available and under investigation for the treatment of HS. HS is still characterized by unmet clinical needs and represents an expanding field in the current scientific research. The aim of this narrative review is to describe the pathological dysregulation of IL-1 family members in HS and to provide an update on therapeutic strategies targeting IL-1 family cytokine signaling. Further clinical and preclinical data may likely lead to the enrichment of the therapeutic armamentarium of HS with IL-1 family cytokine antagonists.

Psoriasis and Fibromyalgia: A Systematic Review.

Psoriasis is a chronic inflammatory cutaneous condition characterized by several comorbidities, including musculoskeletal disorders. While the association with psoriatic arthritis has been widely addressed in literature, the aim of the present systematic review was to identify all available evidence on the relationship between psoriasis and fibromyalgia, a musculoskeletal syndrome primarily characterized by chronic widespread pain. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and MedLine and Web of Science (WOS) databases were searched for literature up to March 2023. After the removal of duplicate records, a total of 11 articles were deemed eligible for inclusion in a qualitative synthesis. Our results suggested that psoriatic patients had a higher prevalence of fibromyalgia (8-30%), with a very high impact on symptoms of psoriasis. Moreover, fibromyalgic patients had a slightly increased prevalence of psoriasis (2.2-6.7%) compared to the control groups. Finally, several studies demonstrated the substantial impact of fibromyalgia on psoriatic outcome measures in patients with concomitant psoriatic arthritis. In conclusion, available data support a potential interplay between psoriasis and fibromyalgia, but further research is encouraged in this area.

MAPK15 controls cellular responses to oxidative stress by regulating NRF2 activity and expression of its downstream target genes.

Oxidation processes in mitochondria and different environmental insults contribute to unwarranted accumulation of reactive oxygen species (ROS). These, in turn, rapidly damage intracellular lipids, proteins, and DNA, ultimately causing aging and several human diseases. Cells have developed different and very effective systems to control ROS levels. Among these, removal of excessive amounts is guaranteed by upregulated expression of various antioxidant enzymes, through activation of the NF-E2-Related Factor 2 (NRF2) protein. Here, we show that Mitogen Activated Protein Kinase 15 (MAPK15) controls the transactivating potential of NRF2 and, in turn, the expression of its downstream target genes. Specifically, upon oxidative stress, MAPK15 is necessary to increase NRF2 expression and nuclear translocation, by inducing its activating phosphorylation, ultimately supporting transactivation of cytoprotective antioxidant genes. Lungs are continuously exposed to oxidative damages induced by environmental insults such as air pollutants and cigarette smoke. Interestingly, we demonstrate that MAPK15 is very effective in supporting NRF2-dependent antioxidant transcriptional response to cigarette smoke of epithelial lung cells. Oxidative damage induced by cigarette smoke indeed represents a leading cause of disability and death worldwide by contributing to the pathogenesis of different chronic respiratory diseases and lung cancer. Therefore, the development of novel therapeutic strategies able to modulate cellular responses to oxidative stress would be highly beneficial. Our data contribute to the necessary understanding of the molecular mechanisms behind such responses and identify new potentially actionable targets.