Association of down-regulation of CD109 expression with up-expression of Smad7 in pathogenesis of psoriasis.

Transforming growth factor (TGF)-ß signaling plays an important role in the pathogenesis of psoriasis. CD109, a novel TGF-ß co-receptor, which inhibits TGF-ß signaling by enhancing Smad7-dependent degradation of TGF-ß type I receptor (TGF-ß RI), is abnormally expressed in psoriasis. To date, the expression of Smad7 and the correlation between CD109 and Smad7 expression in psoriasis have not been fully elucidated. This study was designed to investigate the expression and the correlation of CD109 and TGF-ß signaling associated proteins in psoriasis and their roles in the pathogenesis of psoriasis. Thirty-two psoriasis specimens were subjected to immunohistochemical staining for CD109, Smad7, TGF-ß RI and Ki67. Ten normal skin (NS) specimens served as controls. The positive expression rate (% positive cells) of Smad7 and Ki67 in psoriasis was significantly higher than in NS (62.6%±19.9% vs. 17.2%±4.4%, and 50.7%±14.3% vs. 19.5%±3.2%, respectively, P<0.001), and the expression levels of CD109 and TGF-ß RI were reduced significantly in psoriasis as compared with NS (8.1%±6.7% vs. 35.8%±6.7% and 27.3%±3.4% vs. 3.0%±3.4%, respectively, P<0.001). There were significantly negative correlations between CD109 and Smad7 (r=-0.831, P<0.01). These findings indicated that CD109 might play a certain role in the pathogenesis of psoriasis. Lower expression of CD109 and TGF-ß RI was highly correlated with higher expression of Smad7 and Ki67, suggesting that CD109 may induce the pathogenesis of psoriasis through Smad7-mediated degradation of TGF-ß RI, and lead to the termination of TGF-ß signaling.

Lipoxin A4 inhibits lipopolysaccharide-induced production of inflammatory cytokines in keratinocytes by up-regulating SOCS2 and down-regulating TRAF6.

Liopxin A4 (LXA4) is considered to be a crucial modulator in the inflammatory responses. In the present study, we aimed to study the effect of LXA4 on the inflammatory cytokines production induced by lipopolysaccharide (LPS) and the possible mechanism in normal human epidermal keratinocytes (NHEKs). NHEKs were isolated and cultured. The expression of toll-like receptor 4 (TLR4), LXA4 receptor (ALXR) and aryl hydrocarbon receptor (AhR) in NHEKs was detected by reverse transcription polymerase chain reaction (RT-PCR). The mRNA and protein levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1ß (IL-1ß) were determined in NHEKs stimulated by LPS (10 µg/mL) with or without preincubation with LXA4 (100 nmol/L) for 30 min by real-time quantitative PCR (real-time qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The expression levels of tumor necrosis factor receptor-associated factor 6 (TRAF6) and suppressors of cytokine signaling 2 (SOCS2) mRNAs and proteins, and nuclear translocation of NF-kB-p65 were measured by real-time qPCR and Western blotting, respectively. The results showed that NHEKs expressed TLR4, ALXR and AhR. LXA4 significantly inhibited the mRNA and protein expression levels of TNF-α, IL-1ß and TRAF6 induced by LPS in NHEKs, and LXA4 obviously increased the expression of SOCS2 at mRNA and protein levels. The nuclear NF-kB-p65 protein expression induced by LPS was inhibited after preincubation with LXA4 in NHEKs. It was concluded that LXA4 inhibits the LPS-induced production of TNF-α and IL-1ß in NHEKs by up-regulating SOCS2 and down-regulating TRAF6.

Lipoxin A4 inhibits proliferation and inflammatory cytokine/chemokine production of human epidermal keratinocytes associated with the ERK1/2 and NF-κB pathways.

BACKGROUND: Current in vitro studies show that lipoxin A4 (LXA4) has multiple biological functions including inhibiting cell proliferation and inflammatory cytokine production. Our previous studies showed LXA4 could inhibit the expression of IL-6 and IL-8 in normal human epidermal keratinocytes (NHEKs). However, more specific effects including regulation of cell proliferation and anti-inflammatory mechanisms of LXA4 in NHEKs have not been previously studied. OBJECTIVE: We proposed to investigate the effects of LXA4 on cell proliferation and inflammatory cytokine/chemokine production in NHEKs, and the possible molecular mechanisms of cell cycle and anti-inflammatory signal transduction pathway. METHODS: NHEKs were stimulated with LPS, with or without preincubation with LXA4. Cell proliferation and cell cycle of NHEKs were examined by WST-8, CFSE assay and DNA staining, respectively. The mRNA and protein levels of inflammatory cytokines were quantified by real-time quantitative PCR and ELISA. The expressions of signaling proteins cyclin D1, P16INK4A, ERK1/2 and NF-κB-p65 were analyzed using Western blotting. RESULTS: Cell proliferation and inflammatory cytokine/chemokine production of NHEKs were suppressed by LXA4, which caused G0/G1 phase cell cycle arrest in NHEKs. The expression of cyclin D1 was down-regulated by LXA4, contrary to the results of P16INK4A. The ERK1/2 phosphorylation and NF-κB-p65 nuclear translocation of NHEKs were both suppressed by LXA4. CONCLUSION: Cell growth and inflammatory cytokine/chemokine production of NHEKs were inhibited by LXA4, and the inhibitory effects might be associated with the mechanisms of cyclin D1/P16INK4A, ERK1/2 and NF-κB signal transduction pathway.

High SIPA-1 expression in proximal tubules of human kidneys under pathological conditions.

Systemic lupus erythematosus (SLE) and clear cell renal cell carcinoma (CC-RCC) are serious disorders and usually fatal, and always accompanied with pathological changes in the kidney. Signal-induced proliferation-associated protein 1 (SIPA-1) is a Rap1GTPase activating protein (Rap1GAP) expressed in the normal distal and collecting tubules of the murine kidney. Lupus-like autoimmune disease and leukemia have been observed in SIPA-1 deficient mice, suggesting a pathological relevance of SIPA-1 to SLE and carcinoma in human being. The expression pattern of SIPA-1 is as yet undefined and the pathogenesis of these diseases in humans remains elusive. In this study, we used both immunohistochemistry and quantum dot (QD)-based immunofluorescence staining to investigate the expression of SIPA-1 in renal specimens from SLE and CC-RCC patients. MTT assay and Western blotting were employed to evaluate the effects of SIPA-1 overexpression on the proliferation and apoptosis of renal cell lines. Semi-quantitative reverse transcriptase-PCR (RT-PCR) was applied to examine the changes of hypoxia-inducible factor-1α (HIF-1α) mRNA level. Results showed that SIPA-1 was highly expressed in the proximal and collecting tubules of nephrons in SLE patients compared to normal ones, and similar results were obtained in the specimens of CC-RCC patients. Although SIPA-1 overexpression did not affect cellular proliferation and apoptosis of both human 786-O renal cell carcinoma cells and rat NRK-52E renal epithelial cell lines, RT-PCR results showed that HIF-1α mRNA level was down-regulated by SIPA-1 overexpression in 786-O cells. These findings suggest that SIPA-1 may play critical roles in the pathological changes in kidney, and might provide a new biomarker to aid in the diagnosis of SLE and CC-RCC.

Expression of USP15, TßR-I and Smad7 in psoriasis.

The deubiquitinating enzyme ubiquitin specific peptidase 15 (USP15) is regarded as a regulator of TGFß signaling pathway. This process depends on Smad7, the inhibitory factor of the TGFß signal, and type I TGFß receptor (TßR-I), one of the receptors of TGFß. The expression level of USP15 seems to play vital roles in the pathogenesis of many neoplasms, but so far there has been no report about USP15 in psoriasis. In this study, immunohistochemical staining of USP15, TßR-I and Smad7 was performed in 30 paraffin-embedded psoriasis specimens and 10 normal specimens to investigate the expression of USP15, TßR-I and Smad7 in psoriasis and to explore the relevance among them. And USP15 small interfering RNA (USP15 siRNA) was used to transfect Hacat cells to detect the mRNA expression of TßR-I and Smad7. Of 30 cases of psoriasis in active stage, 28, 24 and 26 cases were positive for USP15, TßR-I and Smad7 staining, respectively. The positive rates of USP15 and Smad7 were significantly higher in psoriasis specimens than in normal skin specimens (44.1%±26.0% vs. 6.1%±6.6%, 47.2%±27.1% vs. 6.6%±7.1%), and positive rate of TßR-I (20.3%±22.2%) in psoriasis was lower than that in normal skin specimens (46.7%±18.2%). There was a significant positive correlation between USP15 and Smad7 expression, and significant negative correlations between USP15 and TßR-expression, an I d between TßR- and Smad7 expression I in psoriasis. After transfection of USP15 siRNA in Hacat cells, the expression of TßR-mRNA was up I -regulated and that of Smad7 was down-regulated. It is concluded that USP15 may play a role in the pathogenesis of psoriasis through regulating the TßR-I/Smad7 pathway and there may be other cell signaling pathways interacting with USP15 to take part in the development of psoriasis.

[Expressions of cystathionine-beta-synthase and cystathionine-gamma-lyase in the corpus cavernosum smooth muscle of castrated rats].

OBJECTIVE: To study the expressions of cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) in the corpus cavernosum smooth muscle of castrated rats and their roles in erectile dysfunction after castration. METHODS: We randomly assigned 40 eight-week-old male SD rats to groups A (2-week sham-operation), B (4-week sham-operation), C (2-week castration) and D (4-week castration). We determined the level of serum testosterone (T) and the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats after operation using immunohistochemistry and RT-PCR. RESULTS: The T level was significantly decreased in groups C ([11.85 +/- 6.73] nmol/L) and D ([1.96 +/- 1.23] nmol/L) as compared with A ([89.65 +/- 17.13] nmol/L) and B ([106.75 +/- 19.68] nmol/L) (P < 0.05). CBS and CSE were expressed in all groups of rats, but the relative expressions of CBS and CSE mRNA were significantly lower in groups C (0.93 +/- 0.14 and 0.87 +/- 0.20) and D (0.79 +/- 0.17 and 0.71 +/- 0.12) than in A (2.13 +/- 0.65 and 1.93 +/- 0.15) and B (2.07 +/- 0.53 and 1.89 +/- 0.45) (P < 0. 05), so were the optical density values (IA) of the CBS and CSE proteins, 130.35 +/- 23.56 and 93.56 +/- 36.64 in group C and 80.29 +/- 29.65 and 58.56 +/- 19.95 in group D, as compared with 310.57 +/- 130.56 and 269.56 +/- 116.76 in group A and 349.68 +/-112.35 and 298.35 +/- 100.76 in group B (P < 0.05). The androgen level was positively correlated with the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats. CONCLUSION: Androgen regulates erectile function via the expressions of CBS and CSE.