Aim: Through their recognition of various bacterial cell wall components, TLR2 and TLR4 participate in the innate response and modulate the activation of adaptive immunity. Therefore, the genetic background of these receptors might play a crucial role in autoimmune diseases such as systemic lupus erythematosus (SLE). In this study, we investigated the possible association between polymorphisms within TLR2 and TLR4 genes with SLE susceptibility. Material and methods: A total of 100 SLE patients and 200 unrelated healthy controls of the Tunisian population were enrolled in the study.TLR4rs4986790, TLR4rs4986791, and TLR2rs5743708 genotyping were performed using a polymerase chain reaction-restriction fragment length polymorphism method. The number of guanine-thymine (GT) repeat microsatellite in the intron 2 of TLR2 gene was analyzed by sequencing. Results:We reported a lack of allelic and genotypic association between SNPs of TLR4 and TLR2 genes and SLE pathogenesis. No correlation was found with any SLE features. However, SLE susceptibility was associated with the GT repeat microsatellite polymorphism in the human TLR2 gene. Further subclassification of alleles into three subclasses revealed a significant association between the long-sized repeats ((GT) >23) and SLE. Conclusion: Though the results showed the absence of genetic association of TLR4 and TLR2 SNPs with the risk of developing SLE, we have identified a protective association between the microsatellite polymorphism in intron 2 of the TLR2 gene and SLE. Functionally, these (GT)n repeats may confer modifying effects or susceptibility to certain inflammatory conditions.

Pemphigus foliaceus (PF) is considered to be caused by the combined effects of susceptibility genes and environmental triggers. The polymorphisms of Toll-like receptors (TLRs) genes have been associated with the risk of various autoimmune diseases. The aim of this study was to evaluate the potential association of TLR2-3-4 and 7 gene polymorphisms with Tunisian PF. Fourteen polymorphisms were analyzed in 93 Tunisian PF patients compared to 193 matched healthy controls: rs5743703-rs5743709 and (GT)n repeat (TLR2); rs5743305, rs3775294, and rs3775291 (TLR3), rs4986790 and rs4986791 (TLR4); and rs3853839 (TLR7). Our results showed that the genetic factors varied depending on the epidemiological feature stratification. In fact, in the whole population, no association with the susceptibility to PF was found. The TLR2 GT repeat seems to be closely associated with PF risk in patients originated from the endemic localities (group 3); the GT18 allele and the heterozygous genotype GT18/GT19 seem to confer risk to endemic PF ( P = 0.02 ; OR = 2.3 [1.1-4.9] and P = 0.0002 , OR = 20 [2.5-171], respectively). In contrast, the GT23 repeat could be considered as protector allele ( P = 0.02 , OR = 0.2 [0.06-0.87]). Furthermore, medium GT alleles which induce high promoter activity were also significantly more frequent in patients versus short or long GT repeats ( P = 0.0018 with OR = 3.26 [1.5-7]). On the other hand, the TLR3-rs574305 AA genotype and A allele were significantly more frequent in patients whose age of the onset was above 35 years (group 2) ( P = 0.038 , OR = 1.78 and P = 0.009 , OR = 3.92 , respectively). Besides, the TLR4>rs3775294 A allele was found to be protector only in patients with sporadic features (groups 2 and 4) ( P = 0.03 , OR = 0.57 [0.3-0.9] and P = 0.006 , OR = 0.24 [0.08-0.74], respectively). No statistically significant difference was observed in the genotypic and allelic frequencies of TLR-4 and TLR-7 gene polymorphisms. The present data suggest that TLR2and TLR3 polymorphisms are significantly associated with increased susceptibility to PF in the Tunisian population.

Introduction: Plenty of biomaterials have been studied for their application in skin tissue engineering. Currently, gelatin-hydrogel is used to support three-dimensional (3D) skin in vitro models. However, mimicking the human body conditions and properties remains a challenge and gelatin-hydrogels have low mechanical properties and undergo rapid degradation rendering them not suitable for 3D in vitro cell culture. Nevertheless, changing the concentration of hydrogels could overcome this issue. Thus, we aim to investigate the potential of gelatin hydrogel with different concentrations crosslinked with genipin to promote human epidermal keratinocytes and human dermal fibroblasts culture to develop a 3D-in vitro skin model replacing animal models.Methods: Briefly, the composite gelatin hydrogels were fabricated using different concentrations as follows 3%, 5%, 8%, and 10% crosslinked with 0.1% genipin or non-crosslinked. Both physical and chemical properties were evaluated.Results and discussion: The crosslinked scaffolds showed better properties, including porosity and hydrophilicity, and genipin was found to enhance the physical properties. Furthermore, no alteration was prominent in both formulations of CL_GEL 5% and CL_GEL8% after genipin modification. The biocompatibility assays showed that all groups promoted cell attachment, cell viability, and cell migration except for the CL_GEL10% group. The CL_GEL5% and CL_GEL8% groups were selected to develop a bi-layer 3D-in vitro skin model. The immunohistochemistry (IHC) and hematoxylin and eosin staining (H&E) were performed on day 7, 14, and 21 to evaluate the reepithelization of the skin constructs. However, despite satisfactory biocompatibility properties, neither of the selected formulations, CL_GEL 5% and CL_GEL 8%, proved adequate for creating a bi-layer 3D in-vitro skin model. While this study provides valuable insights into the potential of gelatin hydrogels, further research is needed to address the challenges associated with their use in developing 3D skin models for testing and biomedical applications.

Pemphigus foliaceus (PF) is a bullous autoimmune skin disease diagnosed through sera and skin analyses. PF severity is associated with maintained anti‐Dsg1 sera levels and its prognosis is unpredictable. MicroRNA (miRNA), dynamic regulators of immune function, have been identified as potential biomarkers for some autoimmune diseases. This study aimed to assess the miRNA expression of miR‐17‐5p, miR‐21‐5p, miR‐146a‐5p, miR‐155‐5p and miR‐338‐3p using quantitative real‐time PCR in peripheral blood mononuclear cells (PBMC) and lesional skin samples from untreated and treated PF patients (both remittent and chronic) over 3 months. Overall, miRNA expression was significantly higher in PBMC than in biopsy samples. Blood miR‐21 expression was increased in untreated patients compared to controls and had a diagnostic value with an AUC of 0.78. After 6 weeks, it decreased significantly, similar to anti‐Dsg1 antibodies and the PDAI score. In addition, a positive correlation was observed between cutaneous miR‐21 expression and the disease activity score. Conversely, cutaneous expressions of miR‐17, miR‐146a and miR‐155 were significantly higher in treated chronic patients compared to remittent ones. The cutaneous level of miR‐155 positively correlated with pemphigus activity, making it a potential predictive marker for patients' clinical stratification with an AUC of 0.86.These findings suggest that blood miR‐21 and cutaneous miR‐155 can be used as supplemental markers for PF diagnosis and activity, respectively in addition to classical parameters.