The protein tyrosine phosphatase, non-receptor type 22 R620W polymorphism does not confer susceptibility to psoriasis in the genetic homogeneous population of Crete

Cannabinoid Signaling in the Skin: Therapeutic Potential of the "C(ut)annabinoid" System

The endocannabinoid system (ECS) has lately been proven to be an important, multifaceted homeostatic regulator, which influences a wide-variety of physiological processes all over the body. Its members, the endocannabinoids (eCBs; e.g., anandamide), the eCB-responsive receptors (e.g., CB₁, CB₂), as well as the complex enzyme and transporter apparatus involved in the metabolism of the ligands were shown to be expressed in several tissues, including the skin. Although the best studied functions over the ECS are related to the central nervous system and to immune processes, experimental efforts over the last two decades have unambiguously confirmed that cutaneous cannabinoid ("c[ut]annabinoid") signaling is deeply involved in the maintenance of skin homeostasis, barrier formation and regeneration, and its dysregulation was implicated to contribute to several highly prevalent diseases and disorders, e.g., atopic dermatitis, psoriasis, scleroderma, acne, hair growth and pigmentation disorders, keratin diseases, various tumors, and itch. The current review aims to give an overview of the available skin-relevant endo- and phytocannabinoid literature with a special emphasis on the putative translational potential, and to highlight promising future research directions as well as existing challenges.

Role of C1858T Polymorphism of Lymphoid Tyrosine Phosphatase in Egyptian Children and Adolescents with Type 1 Diabetes

BACKGROUND

Type 1 Diabetes Mellitus (T1DM) is a multifactorial autoimmune disease. The Protein Tyrosine Phosphatase Non-receptor 22 (PTPN22) gene is an important negative regulator of signal transduction through the T-cell Receptors (TCR). A PTPN22 polymorphism, C1858T, has been found to be a risk determinant for several autoimmune diseases, including T1DM, in different populations.

OBJECTIVE

The present study was aimed to analyze a possible association between the C1858T polymorphism in Egyptian children with T1DM.

METHODS

This case-control study included 240 children divided evenly between T1DM patients and controls. The PTPN22 C1858T polymorphism was genotyped using polymerase chain reaction with Restriction Fragment Length Polymorphism (RFLP).

RESULTS

Both the 1858CΤ and 1858ΤΤ genotypes and the 1858T allele were found more frequently in patients (32.5% and 18.7%, respectively) than in controls (10% and 5.0%, respectively), P=0.013 and P=0.007, respectively. Among females, the 1858T allele was more common in patients (18%) than in controls (2.6%), P=0.014.

CONCLUSION

These findings suggest that the PTPN22 1858T allele could be a T1DM susceptibility factor in the Egyptian population and that it might play a different role in susceptibility to T1DM according to gender in T1DM patients.

The Protein Tyrosine Phosphatase Nonreceptor 22 (PTPN22) R620W Functional Polymorphism in Psoriasis

Background:

Psoriasis is a complex autoimmune disease caused by the interaction of genetic and environmental factors. PTPN22 gene polymorphism has been reported to affect psoriasis susceptibility; however, no data are available for Middle Eastern populations.

Objective:

The aim of this study was to investigate the association of PTPN22 (1858C/T) R620W polymorphism with psoriasis in a Saudi cohort.

Methods:

Saudi subjects (n = 306) including patients with psoriasis (n = 106) and matched controls (n = 200) were studied for PTPN22 variants using tetra-primer amplification refractory mutation system-polymerase chain reaction method. The frequencies of alleles and genotypes of PTPN22 (1858C/T) polymorphism were compared between patients and controls.

Results:

The frequency of CT genotype of PTPN22 (1858C/T) polymorphism was significantly higher, whereas that of CC genotype was lower in patients with psoriasis than in controls (P < .001, relative risk [RR] = 7.151). The homozygous genotype TT was absent in both the patients and healthy controls. The frequency of allele T encoding tryptophan (W) was significantly increased (P < .001, RR = 5.76), whereas that of allele C encoding arginine (R) decreased in psoriasis cases as compared with controls (P < .001, RR = 0.173) indicating that individuals carrying allele T are more susceptible to psoriasis than noncarriers.

Conclusions:

PTPN22 (1858C/T) polymorphism is positively associated with susceptibility of psoriasis in Saudis and can be developed as biomarker for evaluating psoriasis risk. However, further studies on PTPN22 polymorphism in larger samples from different geographical areas and ethnicity are warranted.

The role of PTPN22 C1858T gene polymorphism in diabetes mellitus type 1: first evaluation in Greek children and adolescents

Type 1 diabetes mellitus (T1DM) is an autoimmune multifactorial disease. Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene encodes lymphoid-specific tyrosine phosphatase (Lyp), an inhibitor of T cell activation. PTPN22 C1858T polymorphism was associated with T1DM in populations of Caucasian origin. The aim of this study was the investigation for the first time of the association of PTPN22 C1858T polymorphism with T1DM in Greek population. We studied 130 children and adolescents with T1DM and 135 healthy individuals of Greek origin. The polymorphism was genotyped using polymerase chain reaction with restriction fragment length polymorphism. C1858T and T1858T genotypes as well as 1858T allele were found more frequently in patients (10.8% and 5.8%, resp.) than in healthy individuals (5.9% and 3.0%, resp.) but at non statistically significant level. There was no statistically significant association found with gender, age at diagnosis, severity of onset, history of Hashimoto thyroiditis or family history of T1DM. Increased frequency of 1858T allele in patients than in controls, implying a probable association, agrees with results of similar studies on other populations. The inability to find a statistically significant difference is probably due to the decreased frequency of minor allele in Greek population, indicating the need for a larger sample.

A CD40 and an NCOA5 gene polymorphism confer susceptibility to psoriasis in a Southern European population: a case-control study

Recent genome-wide association studies of many complex diseases have successfully identified novel susceptibility loci, with many of them shared by multiple disease-associated pathways. The genes CD40 and nuclear receptor coactivator 5 (NCOA5), located in a 400-kb region surrounding CD40, have been reported to be associated with increased risk for rheumatoid arthritis and other autoimmune diseases. We hypothesized that those genes may also have a role in psoriasis (PS), an autoimmune, chronic inflammatory skin disease. In a case-control study, 198 patients with PS and 400 controls were genotyped for 2 single nucleotide polymorphisms (SNPs) of the CD40 and NCOA5 genes located on chromosome 20q.12-q13.12. Here, we demonstrate for the first time the association of both SNPs with susceptibility to PS, thus suggesting a putative key role of both genes in multiple autoimmune diseases. Alleles G and C of the CD40 rs4810485 and NCOA5 rs2903908 SNPs, respectively, were more common in individuals with PS than in controls (p = 0.03, odds ratio [OR] = 1.42, 95% confidence interval [95% CI] 1.05-1.95 and p = 0.000 003, OR = 1.93, 95% CI 1.47-2.55, respectively). The identification of shared genetic susceptibility loci may provide insight into our understanding of the pathophysiology of autoimmune diseases.

Association of the PTPN22 R620W polymorphism with increased risk for SLE in the genetically homogeneous population of Crete

Autoimmune diseases affect approximately 5% of the population, but much work remains to define the genetic risk factors and pathogenic mechanisms underlying these conditions. There is accumulating evidence that common genetic factors might predispose to multiple autoimmune disorders. Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are complex autoimmune disorders with multiple susceptibility genes. The functional R620W (C1858T) polymorphism of the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene, a member of the PTPs that negatively regulate T-cell activation, has been recently associated with susceptibility to various autoimmune diseases. The aim of this study was to assess whether the C1858T polymorphism of PTPN22 also confers increased risk for SLE and RA in the genetically homogeneous population of Crete. It was found that the minor T allele of the PTPN22 C1858T SNP was more common in SLE patients than in control individuals (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.11 to 3.9, p = 0.017). No significant difference was observed in the frequency of this allele when RA patients were compared with controls (OR = 1.14, 95% CI = 0.65 to 1.9, p = 0.64). Although the PTPN22 1858 T allele is found at decreased frequency in Southern Europe, including Crete, an association was found between this allele and SLE in the population studied.