Downregulation of Ebp1Khib210 promotes keratinocyte proliferation through induction of TIF-IA-mediated rRNA synthesis.

BACKGROUND: Psoriasis is a prevalent chronic inflammatory dermatosis characterized by excessive proliferation of keratinocytes. Protein lysine 2-hydroxyisobutyrylation (Khib) is a newly identified post-translational modification that regulates various biological processes. Abnormal Khib modification has been closely associated with the development of autoimmune diseases. OBJECTIVE: To investigate the abnormal Khib profile and its pathogenic role in psoriasis. METHODS: We utilized liquid chromatography-tandem mass spectrometry to analyze Khib-modified proteins in the epidermis of psoriasis and healthy controls. Mutated cells and mice with downregulated Ebp1Khib210 were generated to investigate its functional effects in psoriasis. RESULTS: The omic analysis revealed dysregulation of Khib modification in psoriatic lesions, exhibiting a distinct profile compared to controls. We observed the downregulation of Ebp1Khib210 in psoriatic lesions and IMQ-induced psoriatic mice. Notably, the expression of Ebp1Khib210 was upregulated in psoriatic patients following effective treatment. Decreased Ebp1Khib210 enhanced keratinocyte viability, proliferation, and survival while inhibiting apoptosis in vitro. Additionally, Pa2g4K210A mice with downregulated Ebp1Khib210 exhibited more severe psoriatic lesions and enhanced keratinocyte proliferation. Moreover, we found that Ebp1K210A mutation increased the interaction between Ebp1 and nuclear Akt, thereby inhibiting MDM2-mediated TIF-IA ubiquitination, and resulting to increased rRNA synthesis and keratinocyte proliferation. The downregulation of Ebp1Khib210 was attributed to inflammation-induced increases in HDAC2 expression. CONCLUSION: Our findings demonstrate that downregulation of Ebp1Khib210 promotes keratinocyte proliferation through modulation of Akt signaling and TIF-IA-mediated rRNA synthesis. These insights into Khib modification provide a better understanding of the pathogenesis of psoriasis and suggest potential therapeutic targets.

EDIL3 influenced the αvß3-FAK/MEK/ERK axis of endothelial cells in psoriasis.

One of the earliest events in the development of psoriatic lesion is a vascular network expansion. The abnormal vascular network is associated with increased endothelial cells (ECs) survival, proliferation, adhesion, migration, angiogenesis and permeability in psoriatic lesion. Our previous study demonstrated that epidermal growth factor-like repeats and discoidin I-like domains 3 (EDIL3) derived from psoriatic dermal mesenchymal stem cells (DMSCs) promoted cell-cell adhesion, migration and angiogenesis of ECs, but the molecular mechanism of upstream or downstream has not been explored. So, this study aimed to explore the association between EDIL3 derived from DMSCs (DMSCs-derived EDIL3) and psoriasis-associated angiogenesis. We injected recombinant EDIL3 protein to mouse model of psoriasis to confirm the roles of EDIL3 in psoriasis. Besides, we employed both short-interference RNA (si-RNA) and lentiviral vectors to explore the molecular mechanism of EDIL3 promoting angiogenesis in psoriasis. In vivo, this research found that after injected recombination EDIL3 protein, the epidermis thickness and microvessel density were both elevated. EDIL3 accelerated the process of psoriasis in the IMQ-induced psoriasis-like mouse model. Additionally, we confirmed that in vitro DMSCs-derived EDIL3 is involved in the tube formation of ECs via αvß3-FAK/MEK/ERK signal pathway. This suggested that DMSCs-derived EDIL3 and αvß3-FAK/MEK/ERK signal pathway in ECs play an important role in the pathogenesis of psoriasis. And the modification of DMSCs, EDIL3 and αvß3-FAK/MEK/ERK signal pathway will provide a valuable therapeutic target to control the angiogenesis in psoriasis.

Increased angiogenesis and migration of dermal microvascular endothelial cells from patients with psoriasis.

Psoriasis displays both increased angiogenesis and microvascular dilation in the skin, while human dermal microvascular endothelial cells (HDMECs) are involved in angiogenesis and microvascular dilation. Whether the functions of HDMECs are altered in psoriatic skin versus healthy skin remain unknown. Here, we isolated HDMECs from the skin of 10 patients with psoriasis and 10 healthy subjects and compared angiogenesis, proliferation, migration and cell metabolism between psoriatic HDMECs and normal HDMECs. We found that the morphology of primary HDMECs was comparable between psoriatic HDMECs and normal HDMECs. After passage, psoriatic HDMECs displayed larger cell size and wider intercellular space. In addition to DiI-Ac-LDL (DiI-labelled acetylated low-density lipoprotein) uptake, expression levels of CD31, vWF (von Willebrand factor) and LYVE-1 were comparable in psoriatic HDMECs versus normal HDMECs. However, psoriatic HDMECs exhibited increased tube formation (numbers of nodes and meshes, p < 0.05) and migration (numbers of migrated cells, p < 0.001) and reductions in proliferation (growth rates, p < 0.05) and energy metabolism (oxygen consumption rate and extracellular acidification rate, p < 0.05) compared with normal HDMECs. Therefore, psoriatic HDMECs display an increased angiogenesis and migration and decreased proliferation and metabolic activity, suggesting a pathogenic role of HDMECs in psoriasis.

The effects of human dermal-derived mesenchymal stem cells on the keratinocyte proliferation and apoptosis in psoriasis.

Psoriasis is a common chronic inflammatory skin disease, characterized by epidermal hyperproliferation. Mesenchymal stem cells (MSCs) regulate inflammation and vascular proliferation in the psoriasis lesions. Whether dermal-derived mesenchymal stem cells (DMSCs), the main MSCs in the dermis, regulate keratinocyte proliferation and apoptosis remains unknown. In the present study, we assessed the proliferation and apoptosis of keratinocytes cocultured with DMSCs isolated from either normal or psoriatic involved skin. Cell growth and apoptotic rates were determined using Cell Count Kit-8 and annexin V-FITC staining, respectively. In addition, EDU kit was also used to measure the rate of keratinocyte proliferation. Our results showed that psoriatic DMSCs (pDMSCs) were more potent than normal DMSCs (nDMSCs) in stimulating keratinocyte proliferation. In contrast, the apoptotic rate and expression levels of caspase-3 protein were lower in pDMSC-treated than nDMSC-treated keratinocytes (p < 0.001). Moreover, significantly higher contents of IL-6, IL-8, TNF-α and IFN-γ were found in the culture medium of pDMSCs than in that of nDMSCs. In conclusion, pDMSCs were more potent than nDMSCs in stimulation of keratinocyte proliferation and secretion of proinflammatory cytokines, but weaker in promoting apoptosis.

Dermal mesenchymal stem cells promoted adhesion and migration of endothelial cells by integrin in psoriasis.

The unusual dilatation of dermal capillaries and angiogenesis played important roles in psoriasis. Some genes and proteins of dermal mesenchymal stem cells (DMSCs) from psoriasis are abnormal and related to the function of endothelial cells (ECs). The present study was aimed to evaluate whether psoriatic DMSCs could affect adhesion and migration of ECs through neovascularization-related integrins in psoriasis. Human DMSCs, collected from psoriasis lesions and healthy skin, respectively, were cocultured with human umbilical vein endothelial cells (HUVECs). The expression levels of three integrins, that is, αvß3, αvß5, and α5ß1 in HUVECs were tested by quantitative real-time polymerase chain reaction and Western blot analysis. The adhesion and migration of HUVECs were detected by adhesion assay and migration assay. The results showed that in psoriasis group, the expression of αVß3 and α5ß1 of HUVECs markedly increased 2.50- and 3.71-fold in messenger RNA levels, and significantly increased 1.63- and 1.92-fold in protein levels, comparing to healthy control group (all p < .05). But ß5 was not significantly different between the two groups (p > .05). In addition, compared with control, psoriatic DMSCs promoted HUVECs adhesion by 1.62-fold and migration by 2.91-fold (all p < .05). In conclusion, psoriatic DMSCs impact HUVECs adhesion and migration by upregulating the expression of integrins αVß3 and α5ß1.

Multi-omics study in monozygotic twins confirm the contribution of de novo mutation to psoriasis.

BACKGROUND: Genome-wide association studies have identified over 120 risk loci for psoriasis. However, most of the variations are located in non-coding region with high frequency and small effect size. Pathogenetic variants are rarely reported except HLA-C*0602 with the odds ratio being approximately 4.0 in Chinese population. Although rare variations still account for a small proportion of phenotypic variances in complex diseases, their effect on phenotypes is large. Recently, more and more studies focus on the low-frequency functional variants and have achieved a certain amount of success. METHOD: Whole genome sequencing and sanger sequencing was performed on 8 MZ twin pairs discordant for psoriasis to scan and verified the de novo mutations (DNMs). Additionally, 665 individuals with about 20 years' medical history versus 2054 healthy controls and two published large population studies which had about 8 years' medical history (including 10,727 cases versus 10,582 controls) were applied to validate the enrichment of rare damaging mutations in two DNMs genes. Besides, to verify the pathogenicity of candidate DNM in C3, RNA-sequencing for CD4+, CD8+ T cells of twins and lesion, non-lesion skin of psoriasis patients were carried out. Meanwhile, the enzyme-linked immunosorbent assay kit was used to detect the level of C3, C3b in the supernatant of peripheral blood. RESULT: A total of 27 DNMs between co-twins were identified. We found six of eight twins carry HLA-C∗0602 allele which have large effects on psoriasis. And it is interesting that a missense mutation in SPRED1 and a splice region mutation in C3 are found in the psoriasis individuals in the other two MZ twin pairs without carrying HLA-C*0602 allele. In the replication stage, we found 2 loss-of-function (LOF) variants of C3 only in 665 cases with about 20 years' medical history and gene-wise analysis in 665 cases and 2054 controls showed that the rare missense mutations in C3 were enriched in cases (OR = 1.91, P = 0.0028). We further scanned the LOF mutations of C3 in two published studies (about 8 years' medical history), and found one LOF mutation in the case without carrying HLA-C*0602. In the individual with DNM in C3, RNA sequencing showed the expression level of C3 in skin was significant higher than healthy samples in public database (TPM fold change = 1.40, P = 0.000181) and ELISA showed protein C3 in peripheral blood was higher (~2.2-fold difference) than the other samples of twins without DNM in C3. CONCLUSION: To the best of our knowledge, this is the first report that DNM in C3 is the likely pathological mutations, and it provided a better understanding of the genetic etiology of psoriasis and additional treatments for this disease.

Psoriasis-associated angiogenesis is mediated by EDIL3.

The dermal mesenchymal stem cells (DMSCs) from psoriasis display higher expression level of epidermal growth factor-like repeats and discoidin I-like domains 3 (EDIL3), while EDIL3 can bind integrins, including αvß3 and αvß5, to regulate angiogenesis. To assess the role of EDIL3 derived from DMSCs of psoriasis (P-DMSCs) in angiogenesis, in vitro, EDIL3 of DMSCs from psoriasis was silenced by interfering EDIL3. Then the efficacy of silencing EDIL3 was tested by fluorescent flag, qRT-PCR and western blotting. And, in vitro, the relationship of EDIL3 in DMSCs with the angiogenesis of HUVECs were investigated through co-culture system. In vivo, EDIL3 recombinant protein was injected into IMQ cream-induced psoriasis-like skin lesions of mouse and EDIL3-associated tube formation were determined using Image J software. Our results showed the capacity of the adhesion, migration and tube formation of HUVECs in all psoriatic DMSCs groups were significantly higher compared with the control and si-EDIL3 groups (all P<0.05) in vitro. Moreover, under stimulated by EDIL3 recombinant protein, EDIL3-associated tube formation was dramatically elevated in vivo (P<0.01). In this study, EDIL3 could promote the adhesion, migration and tube formation of ECs and participant in the angiogenesis pathogenesis of psoriasis through affecting biological function on ECs both in vitro and in vivo. The results suggest a potential role of the critical pro-angiogenic factor EDIL3 in psoriasis therapy.

Comparison of microarray and RNA-Seq analysis of mRNA expression in dermal mesenchymal stem cells.

OBJECTIVE: We characterized mRNA expression profiles in normal and psoriatic human dermal mesenchymal stem cells (DMSCs) to provide a reference for future investigation of differential gene expression in DMSCs. RESULTS: Microarray and RNA sequencing (RNA-Seq) analyses both identified 23 differentially expressed genes using both platforms. The results showed comparable upregulation or downregulation for 14/23 genes using either platform and a 100 % coincidence rate was found by real-time PCR. For all of the differentially expressed genes that were verified by real-time PCR, the coincidence rate for RNA-Seq and real-time PCR was significantly higher than that for microarray analysis and real-time PCR (83.3 vs. 37.5 %, P < 0.0001). Furthermore, RNA-Seq revealed the presence of over 2300 novel transcription tags. CONCLUSION: Relative to microarray analysis, RNA-Seq is more accurate in identifying differentially expressed genes in DMSCs.

Biological characteristics and gene expression pattern of bone marrow mesenchymal stem cells in patients with psoriasis.

Mesenchymal stem cells (MSCs) have immunoregulatory and proangiogenic effects and are suggested to be involved in the pathological processes of immune-related diseases, including psoriasis. Biological characteristics of bone marrow MSCs (BMSCs) from patients with autoimmune diseases, such as systemic lupus erythematosus or rheumatoid arthritis, but not psoriasis, have been characterized. We compared the gene expression profile and biological characteristics of BMSCs from patients with psoriasis and healthy controls. Although the phenotype, differentiation potential and ability to support CD34(+) cell proliferation were similar to those of normal BMSCs, psoriatic BMSCs showed aberrant proliferative activity, increased apoptosis rate and a characteristic gene expression profile. These aberrations may develop after the abnormal immune response in psoriasis and result in BMSC dysfunction. The functionally deficient BMSCs may then fail to suppress overactive immune cells, thereby contributing to the pathogenesis of psoriasis.

IL-17A is involved in the hyperplasia of blood vessels in local lesions of psoriasis by inhibiting autophagy.

OBJECTIVE: Increased angiogenesis is a pathological feature of psoriasis, but the pathomechanisms of angiogenesis in psoriasis are not clear. Interleukin-17A (IL-17A) is the major effect factor in the pathogenesis of psoriasis. Our results showed that IL-17A can promote angiogenesis and cause endothelial cell inflammation. Autophagy plays an important role not only in regulating inflammation, but also in regulating angiogenesis. Whether angiogenesis in psoriasis is related to autophagy remains unclear. In this study, we treated human umbilical vein endothelial cells (HUVECs) with IL-17A to simulate increased angiogenesis to study whether increased angiogenesis in psoriasis is related to autophagy. METHODS AND RESULTS: Our results showed that treatment of HUVECs with IL-17A significantly increased angiogenesis and expression levels of mRNA for multiple proinflammatory cytokines (CCL20, IL-8, CCL2, IL-6, and IL-1ß) and, while decreasing intracellular levels of nitric oxide (NO) and NO synthase (NOS) activity. Moreover, IL-17A inhibited autophagy as shown that IL-17A significantly increased expression levels of LC3II and p62 proteins. Induction of autophagy ameliorated IL-17A-mediated inflammatory response and inhibited angiogenesis, accompanied by increased p-AMPKα(Thr172) and p-ULK1(Ser555) expression, and decreased p-mTOR(Ser2448) and p-ULK1(Ser757) expression. Furthermore, inhibition of either AMPK or lysosomal acidification completely overrode autophagy-induced changes in angiogenesis and NOS activity. Finally, induction of autophagy decreased apoptosis and caspase-3 activity in IL-17A-treated HUVECs. CONCLUSIONS: These results showed that IL-17A is involved in angiogenesis and inflammatory response by inhibiting autophagy through AMPK signaling pathway, suggesting that autophagy may be a new therapeutic target for psoriasis.

EDIL3 and VEGF Synergistically Affect Angiogenesis in Endothelial Cells.

Background: Angiogenesis is one of the histologically predominant characteristics of psoriasis. Vascular endothelial growth factor (VEGF) and epidermal growth factor-like repeats and discoidin I-like domains 3 (EDIL3) have critical effects on angiogenesis. Both these proteins are vital proangiogenic factors in tumor occurrence and progression; however, the relationship between EDIL3 and VEGF with psoriasis remains unclear. Objective: We aimed to elucidate the role of EDIL3 and VEGF and the involved mechanisms in psoriasis-associated angiogenesis. Methods: EDIL3 and VEGF expression in cutaneous tissue was determined by immunohistochemical assay. The effects of EDIL3 on VEGF, VEGFR2, and the growth, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) were analyzed by Western blotting assay, cell counting kit-8 assay, Transwell assay, and Matrigel tube formation assay. Results: EDIL3 and VEGF levels in psoriatic lesions significantly increased as compared to those in normal individuals and showed a positive relationship with the Psoriasis Area and Severity Index. The downregulation of EDIL3 decreased VEGF and VEGFR2 expression in HUVECs. Moreover, the decreased expression of EDIL3 and VEGF reduced the growth, invasion, and tube formation abilities of HUVECs, while EDIL3 resistance to VEGF and VEGFR2 was restored by using the EDIL3 recombinant protein. Conclusion: These results suggest that psoriasis is also characterized by EDIL3 and VEGF-mediated angiogenesis. Thus, EDIL3 and VEGF could serve as novel targets for treating psoriasis.

Autophagy Inhibits Inflammation via Down-Regulation of p38 MAPK/mTOR Signaling Cascade in Endothelial Cells.

Objective: Autophagy, an intracellular process of self-digestion, has been shown to modulate inflammatory responses. In the present study, we determined the effects of autophagy on inflammatory response induced by M5 cytokines. Methods: Human umbilical vein endothelial cells (HUVECs) were treated with M5 cytokines to induce inflammation. Expression levels of mRNA for inflammatory cytokines and BIRC2 were compared in HUVECs with vs without induction of autophagy with rapamycin (RAPA) by PCR, while cell apoptosis was assessed by flow cytometry and caspase-3 activity assay kit. Expression levels of LC3, p62, p-p38 MAPK (Thr180/Tyr182), p-mTOR (Ser2445) and p-ULK1 (Ser555) proteins were measured by Western blotting. The nitric oxide (NO) content, NO synthase (NOS) activity and cell angiogenesis were also evaluated. Results: Induction of autophagy with RAPA decreased expression levels of IL6, IL8 and CCL20, in addition to reduction in inflammation-induced apoptosis in HUVECs. Moreover, RAPA increased LC3II, while decreasing p62 expression. Likewise, expression levels of p-p38 MAPK and p-mTOR proteins were markedly decreased by the treatment with RAPA. Finally, RAPA treatment increased the NO content and the NOS activity, and inhibited angiogenesis. Conclusion: Induced autophagy can improve the function of endothelial cells in psoriasis, suggesting approaches to induce autophagy can be used to ameliorate psoriasis.

Del-1 in Psoriasis Induced the Expression of αvß3 and α5ß1 in Endothelial Cells.

OBJECTIVE: Psoriasis is a chronic inflammatory skin disease highly depending on angiogenesis. Our prior results showed that the mRNA and protein of Del-1 in dermal mesenchymal stem cells (dMSCs) was up-regulated from psoriasis. Our aim was further to investigate the role of Del-1 from dMSCs in the pathogenesis of psoriasis and confirm the effect of Del-1 on the pathogenesis of psoriasis. METHODS: We conducted an immunohistochemistry experiment to further investigate the expression of Del-1in psoriatic lesions. In addition, dMSCs with over-expressed Del-1 via the lentiviral vector of Del-1 were co-cultured with ECs, and the protein expression of integrins (αvß3, αvß5 ,and α5ß1) of ECs were detected by western blotting. RESULTS: This research showed that Del-1 was significantly increased in lesions of patients with psoriasis (p< .05, 9.96 vs. 2.18), and Del-1 from dMSCs successfully induced up-regulation of integrins α5ß1 and αvß3 (all p < .05). CONCLUSION: This study demonstrated that Del-1 from dMSCs was involved in the pathogenesis of psoriasis through induced angiogenesis. And Del-1, αvß3 and α5ß1 may be potential new targets for inhibiting angiogenesis in psoriasis.

Variants in PRKCE and KLC1, Potential Regulators of Type I Psoriasis.

Purpose: Psoriasis is a multifactorial disease with a complex genetic predisposition. The pathophysiology of psoriasis is associated with genetic variants. To better characterize gene variants in psoriasis and identify the relationship between clinical characteristics and variant genes in its pathogenesis. Patients and Methods: DNA was extracted and purified from eight pairs of monozygotic twins with psoriasis discordance and 282 type I psoriasis patients. Thirteen variable genes were amplified and sequenced using the Sanger method after whole genome sequencing. Results: Thirteen genes were found to be variable in eight pairs of monozygotic twins with psoriasis discordance. Among the 13 genes, the variant frequencies of protein kinase C epsilon (PRKCE) (c.240T>C, 35.9% vs 47.7%, P < 0.05) and kinesin light chain 1 (KLC1) (c.216A>G, 2.9% vs 98.1%, P< 0.01) were significantly lower in psoriasis than in normal Asian individuals. Additionally, we found considerable differences in the relationship between variants in genes CADM2, JPH2, SPTLC3 and clinical characteristics stratified by medical history and family history. Moreover, the variants in MEGF6 (39.52% vs 22.50%, χ 2=3.83, p < 0.05) showed a stronger association with the mild group (PASI ≤10) than the heavy group. Conclusion: Our results provide a comprehensive correlation analysis of regulatory genes that are regulated in psoriasis. This integrated analysis offers novel insight into the pathogenic mechanisms involved in psoriasis.

Immunomodulatory effect of psoriasis-derived dermal mesenchymal stem cells on TH1/TH17 cells.

T cell-mediated inflammation plays an important role in the development of psoriasis. Mesenchymal stem cells (MSCs) are a population of multipotent cells that regulate the T cell-mediated immune response. To investigate the effects of psoriatic dermal mesenchymal stem cells (p-DMSCs) on proliferation, apoptosis and differentiation of T cells. p-DMSCs and normal DMSCs (n-DMSCs) were isolated from psoriatic skin and normal healthy controls, respectively, and co-cultured with activated T cells isolated from healthy volunteers using a Transwell system. Proliferation and apoptosis of T cells were assessed by cell count and flow cytometry, respectively. Expression levels of transcription factors associated with subtypes of T cells and cytokines were measured by qRT-PCR and western blot. Both p-DMSCs and n-DMSCs inhibited T cell proliferation and cytokine production. Similarly, the presence of p-DMSCs and n-DMSCs decreased the expression levels of both T-bet and ROR-γt in T cells. However, n-DMSCs exhibited a stronger inhibitory effect than p-DMSCs on T cell proliferation, cytokine production, and T-bet and ROR-γt expression. These results suggest that the effect of p-DMSCs on T cell function could contribute, at least in part, to the pathogenesis of psoriasis.

Dysregulated Dermal Mesenchymal Stem Cell Proliferation and Differentiation Interfered by Glucose Metabolism in Psoriasis.

BACKGROUND AND OBJECTIVES: Psoriasis is a chronic inflammatory skin disease, which the mechanisms behind its initiation and development are related to many factors. DMSCs (dermal mesenchymal stem cells) represent an important member of the skin microenvironment and play an important role in the surrounding environment and in neighbouring cells, but they are also affected by the microenvironment. We studied the glucose metabolism of DMSCs in psoriasis patients and a control group to reveal the relationship among glucose metabolism, cell proliferation activity，and VEC (vascular endothelial cell) differentiation in vitro, we demonstrated the biological activity and molecular mechanisms of DMSCs in psoriasis. METHODS AND RESULTS: We found that the OCR of DMSCs in psoriatic lesions was higher than that in the control group, and mRNA of GLUT1 and HK2 were up-regulated compared with the control group. The proliferative activity of DMSCs in psoriasis was reduced at an early stage, and mRNA involved in proliferation, JUNB and FOS were expressed at lower levels than those in the control group. The number of blood vessels in psoriatic lesions was significantly higher than that in the control group (p<0.05), which the mRNA of VEC differentiation, CXCL12, CXCR7, HEYL and RGS5 tended to be increased in psoriatic lesions compared to the control group, in addition to Notch3. CONCLUSIONS: We speculated that DMSCs affected local psoriatic blood vessels through glucose metabolism, and the differentiation of VECs, which resulted in the pathophysiological process of psoriasis.

Variation at ACOT12 and CT62 locus represents susceptibility to psoriasis in Han population.

BACKGROUND: Psoriasis is a chronic inflammatory disorder of the skin, and genetic factors are reported to be involved in the disease pathogenesis. Many studies have named psoriasis candidate genes. OBJECTIVE: In this study, we determined the mutation frequency of 7 variable genes in 1,027 psoriatic patients and investigated its possible mechanism associated with psoriasis. METHOD: A total of 7 variable genes from 1,027 psoriatic patients were amplified and sequenced using the Sanger method. The mutation frequency was compared to that of non-psoriatic individuals in Asia using information from databases. RESULTS: Among the 7 investigated genes, the mutation frequency of ACOT12 (c.80A>G, 9.98% vs. 5.85%, p < .05) and CT62 (c.476C>T,15.8% vs. 9.93%, p < .05) was found to be significantly higher than among non-psoriatic Asian individuals. The mutation frequencies of CASZ1(c.599T>G), SPRED1(c.155A>G), and ACOT12 (c.80A>G) differed significantly between the groups organized by medical history, PASI, and family history. SPRED1 gene variants (17.25% vs. 7.78%, p < .01) showed a stronger association with the family history group at the onset of psoriasis than with the no family history group. CONCLUSIONS: Our results provide a comprehensive correlation analysis of susceptibility genes in psoriasis patients. Clinical characteristics of patients play important roles in the development of psoriatic skin.

Promoter methylation status of p15 and p21 genes in HPP-CFCs of bone marrow of patients with psoriasis.

Psoriasis is an inflammatory disease related to dysfunctional immunity. The dysfunctional immunity may influence the haematopoietic microenvironment or haematopoiesis in psoriasis. However, direct evidence is lacking. Our objective was to investigate the proliferation of hematopoietic cells from psoriatic patients and any link between the promoter methylation status of p15 and p21 genes and the colony formation ability of high proliferative potential colony-forming cells (HPP-CFCs). Marrow mononuclear cells were isolated from the bone marrow of psoriatic patients and normal controls by density gradient centrifugalization. Colony forming assays of HPP-CFCs were performed in vitro in methylcellulose semi-solid culture medium. mRNA expression and the promoter methylation status of p15 and p21 genes in HPP-CFCs were studied by semi-quantitative RT-PCR and methylation-specific PCR respectively. In methycellulose semi-solid culture system, the colony count of HPP-CFCs in bone marrow of psoriatic patients was significantly less than that of normal controls. Moreover, significantly lower positive frequencies of promoter methylation and higher transcription levels for p15 and p21 genes were observed in psoriasis in comparison to normal volunteers. The lower promoter methylation of p15 and p21 genes may be an important mechanism for the dysfunctional growth regulation pathways in HPP-CFCs in psoriasis.