Jia Zhang

PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-γ AGONISTS ATTENUATE ANGIOTENSIN II-INDUCED COLLAGEN TYPE I EXPRESSION IN ADVENTITIAL FIBROBLASTS

1 Angiotensin (Ang) II‐mediated oxidative stress may be important in enhanced adventitial fibroblast collagen formation. The aim of the present study was to test whether PPAR‐γ agonists 15‐deoxy‐Δ12,14‐prostaglandin J2 (15d‐PGJ2) and pioglitazone could alter AngII‐induced collagen type I formation in vascular adventitial fibroblasts via reactive oxygen species (ROS). 2 Vascular adventitial fibroblasts were isolated from rat thoracic aortas of male Sprague‐Dawley rats and treated with different concentrations of AngII for different periods of time. The expression of collagen type I induced by AngII was examined by western blot. Expression of PPAR‐γ mRNA was examined by reverse transcription–polymerase chain reaction (RT‐PCR). Intracellular ROS generation was measured by flow cytometry. Activation of transcription factors nuclear factor (NF)‐κB and activator protein (AP)‐1 was assessed by an electrophoretic mobility shift assay. 3 Angiotensin II increased expression of collagen type I in a time‐ and dose‐dependent manner in adventitial fibroblasts. In addition, AngII stimulated intracellular generation of ROS in adventitial fibroblasts. Pretreatment of cells with 15d‐PGJ2 and pioglitazone attenuated collagen type I expression and generation of ROS induced by AngII, respectively. Moreover, we observed that N‐acetylcysteine inhibited collagen type I expression induced by AngII as did the PPAR‐γ agonists. Angiotensin II treatment activated the redox‐sensitive transcription factors NF‐κB and AP‐1, whereas pretreatment with 15d‐PGJ2 and pioglitazone reduced the AngII‐induced DNA‐binding activity of NF‐κB but not AP‐1. 4 Our data demonstrate that the PPAR‐γ agonists 15d‐PGJ2 and pioglitazone attenuate AngII‐mediated collagen type I expression in adventitial fibroblasts, which may be mediated by the modulation of ROS release and the redox‐sensitive transcription factor NF‐κB.

CHANGES IN THE COMPOSITION OF THE THORACIC AORTIC WALL IN SPONTANEOUSLY HYPERTENSIVE RATS TREATED WITH LOSARTAN OR SPIRONOLACTONE

1 In the present study, we compared the elastin and collagen content of thoracic aortic medial and adventitial layers from Wistar‐kyoto (WKY) and spontaneously hypertensive rats (SHR). In addition, the effects of losartan, an angiotensin II receptor antagonist, and spironolactone, a mineralocorticoid receptor antagonist, on collagen and elastin content were determined. 2 Prehypertensive (4‐week‐old) and hypertensive (16‐week‐old) SHR were randomly divided into three groups treated with either 0.9% NaCl, losartan (20 mg/kg per day) or spironolactone (200 mg/kg per day). Prehypertensive and hypertensive SHR were treated for 12 and 16 weeks, respectively. Age‐matched WKY rats were not treated with NaCl, losartan or spironolactone and served as the control group. 3 The medial and adventitial layers of the thoracic aorta were composed mainly of elastin and collagen, respectively, in both SHR and WKY rats. Compared with WKY rats, SHR exhibited greater collagen and elastin content in the media, but decreased collagen and elastin content in the adventitial layer. Both medial and adventitial collagen and elastin content increased significantly with age in both strains and was greater in 32‐week‐old rats compared with 16‐week‐old rats. Spironolactone treatment decreased collagen content in the media of thoracic aortas from prehypertensive SHR, whereas losartan decreased collagen content in the media of aortas from hypertensive SHR. In contrast, neither spironolactone nor losartan had any effect on adventitial collagen content in prehypertensive and hypertensive SHR. Medial collagen and elastin were positively related to pulse pressure (PP), but there was no correlation between adventitial mass or collagen content and PP or mean arterial pressure in untreated and treated SHR and WKY rats. 4 In conclusion, the composition of the medial and adventitial layers of the thoracic aorta differs and treatment of SHR with losartan and spironolactone decreases collagen content when delivered at the hypertensive or prehypertensive stage, respectively. However, neither drug has any effect on adventitial collagen content in SHR.

Peroxisome proliferator-activated receptor γ regulates angiotensin II-induced catalase downregulation in adventitial fibroblasts of rats.

Peroxisome proliferator‐activated receptor (PPAR) γ ligands oppose the effect induced by angiotensin II (Ang II) to reduce oxidative stress and improve antioxidant status. In this study, Ang II inhibited catalase (CAT) and peroxisome proliferator‐activated receptor γ (PPAR γ) protein and mRNA expressions. Transfection with PPAR γ small‐interfering RNA (siRNA) led to a reduction in CAT expression. PPAR γ ligands enhanced CAT expression and inhibited extracellular signal‐regulated kinase 1/2 activation. We further reveal that Ang II type 1 receptor is not involved in the inhibitory effects of PPAR γ ligands on Ang II stimulatory events.

Adventitial gene transfer of catalase attenuates angiotensin II-induced vascular remodeling

Vascular adventitia and adventitia-derived reactive oxygen species (ROS) contribute to vascular remodeling following vascular injury. A previous ex vivo study in adventitial fibroblasts showed that catalase, one of most important anti-oxide enzymes, was downregulated by angiotensin II (AngII). The aim of the present study was to investigate whether adventitial gene transfer of catalase affects AngII-induced vascular remodeling in vivo. Adenoviruses co-expressing catalase and enhanced green fluorescent protein (eGFP) or expressing eGFP only were applied to the adventitial surface of common carotid arteries of Sprague-Dawley rats. Alzet minipumps administering AngII (0.75 mg/kg/day) were then implanted subcutaneously for 14 days. Systolic blood pressure and biological parameters of vascular remodeling were measured in each group. Adventitial fibroblasts were cultured and p38 mitogen-activated protein kinase (MAPK) phosphorylation was measured using western blot analysis. The results showed that adventitial gene transfer of catalase had no effect on AngII-induced systolic blood pressure elevation. However, catalase adenovirus transfection significantly inhibited AngII-induced media hypertrophy compared with that of the control virus (P<0.05). In addition, catalase transfection significantly attenuated AngII-induced ROS generation, macrophage infiltration, collagen deposition and adventitial α-smooth muscle actin expression. Furthermore, catalase transfection significantly inhibited the AngII-induced increase in p38MAPK phosphorylation. In conclusion, the results of the present study demonstrated that adventitial gene transfer of catalase significantly attenuated AngII-induced vascular remodeling in rats via inhibition of adventitial p38MAPK phosphorylation.

Mutations in IL36RN are associated with geographic tongue

Geographic tongue (GT) is a benign inflammatory disorder of unknown etiology. Epidemiology and histopathology in previous studies found that generalized pustular psoriasis (GPP) is a factor associated with GT, but the molecular mechanism remains obscure. To investigate the mechanism of GT, with and without GPP, three cohorts were recruited to conduct genotyping of IL36RN, which is the causative gene of GPP. In a family spanning three generations and diagnosed with only GT (“GT alone”), GT was caused by the c.115+6T>C/p.Arg10ArgfsX1 mutation in the IL36RN gene. An autosomal dominant inheritance pattern with incomplete penetrance was observed. In the cohort consisting of sporadic cases of “GT alone” (nxa0=xa048), significant associations between GT and three IL36RN variants (c.115+6T>C/p.Arg10ArgfsX1, c.169G>A/p.Val57Ile and c.29G>A/p.Arg10Gln) were shown. In the GPP patient cohort (nxa0=xa056) and GPP family member cohort (nxa0=xa067), a significant association between the c.115+6T>C mutation and the simultaneous presence of GPP and GT was observed when compared to the presence of GPP without GT (Pxa0<xa00.05). Biopsies revealed similarities among GT patients with different genotypes (AA, Aa and aa), with the neutrophils prominently infiltrating the epidermis. Western-blot analysis showed that the expression ratio of IL-36Ra/IL-36γ in lesioned tongues with individuals harboring different genotypes (AA, Aa and aa, nxa0=xa03, respectively) decreased significantly compared to controls (nxa0=xa03). We describe the mechanism of GT for the first time: some cases of GT are caused by IL36RN mutations, while those lacking mutations are associated with an imbalance in expression between IL-36Ra and IL-36γ proteins in tongue tissue.

Nagashima-type palmoplantar keratosis in a Chinese Han population.

Nagashima-type palmoplantar keratosis (NPPK) is an autosomal recessive form of palmoplantar keratoderma (PPK), which is caused by mutations in the SERPINB7 gene. NPPK has only been reported in Japanese and Chinese populations. The present study was conducted on 12 unrelated Chinese patients who were clinically predicted to suffer from NPPK. Mutation screening was performed by direct sequencing of the entire coding regions of SERPINB7, SLURP1, AQP5, CSTA, KRT1 and KRT9 genes. Direct sequencing of SERPINB7 revealed five homozygous founder mutations (c.796C>T) and four compound heterozygous mutations in nine patients, including one novel mutation (c.122_127delTGGTCC). Nine out of the 12 patients were diagnosed with NPPK due to SERPINB7 pathogenic mutations, and the results expanded the known mutation spectrum of NPPK. Taking the other seven reported Chinese patients, who had been definitively diagnosed with NPPK by genetic testing, into account, the present study further demonstrated that NPPK is a common entity in Mainland China, and c.796C>T is the most prevalent mutation and exerts a founder effect. Furthermore, the NPPK cases described in the current study presented a consistently mild phenotype, as compared with the degrees of phenotypic variability associated with other types of relatively severe PPK, including Mal de Meleda and Olmsted syndrome.

Lentiginous phenotypes caused by diverse pathogenic genes (SASH1 and PTPN11): clinical and molecular discrimination

Pathogenic mutations in genes (SASH1 and PTPN11) can cause a rare genetic disorder associated with pigmentation defects and the well‐known LEOPARD syndrome, respectively. Both conditions presented with lentiginous phenotypes. The aim of this study was to arrive at definite diagnoses of three Chinese boys with clinically suspected lentigines‐related syndromes. ADAR1, ABCB6, SASH1 and PTPN11 were candidate genes for mutational screening. Sanger sequencing was performed to identify the mutations, whereas bioinformatic analysis was used to predict the pathogenicity of novel missense mutations. Two novel mutations c.1537A>C (p.Ser513Arg) and 1527_1530dupAAGT (p.Leu511Lysfs*21) in SASH1 and a common p.Thr468Met mutation in PTPN11 were detected in three pediatric patients with lentiginous phenotypes, respectively. Comparisons between clinical presentations showed that SASH1‐related phenotypes can exhibit hyper‐ and hypopigmentation on the trunk and extremities, similar to dyschromatosis, while scattered café au‐lait spots usually appeared in PTPN11‐related LEOPARD syndrome. Furthermore, the similarity in the clinical presentations of Peutz–Jeghers syndrome, Laugier–Hunziker syndrome, xeroderma pigmentosum, neurofibromatosis type I, suggesting that these conditions should be added into the differential diagnoses of lentiginous phenotypes.

Molecular screening strategies for NF1-like syndromes with café-au-lait macules (Review)

Multiple café-au-lait macules (CALM) are usually associated with neurofibromatosis type 1 (NF1), one of the most common hereditary disorders. However, a group of genetic disorders presenting with CALM have mutations that are involved in human skin pigmentation regulation signaling pathways, including KIT ligand/KIT proto-oncogene receptor tyrosine kinase and Ras/mitogen-activated protein kinase. These disorders, which include Legius syndrome, Noonan syndrome with multiple lentigines or LEOPARD syndrome, and familial progressive hyperpigmentation) are difficult to distinguish from NF1 at early stages, using skin appearance alone. Furthermore, certain syndromes are clinically overlapping and molecular testing is a vital diagnostic method. The present review aims to provide an overview of these ‘NF1-like’ inherited diseases and recommend a cost-effective strategy for making a clear diagnosis among these diseases with an ambiguous borderline.

Generalized eruptive keratoacanthoma with vitiligo followed by the development of prurigo nodularis: A case report and published work review

Herein, we report a unique case of generalized eruptive keratoacanthoma (GEKA) in a 47‐year‐old Chinese man presenting with extensive pruritic papules and nodules accompanied by oral lesions. He also had a 2‐year history of vitiligo and long‐term experience of working outdoors. Biopsies were consistent with keratoacanthoma . Interestingly, prurigo nodularis (PN) was found in histopathology at 1‐year follow up. To our knowledge, this is the first report describing a case of GEKA with oral lesions complicated with vitiligo and developed with PN.

LUMBAR syndrome: A case manifesting as cutaneous infantile hemangiomas of the lower extremity, perineum and gluteal region, and a review of published work

We herein report a rare case of LUMBAR syndrome. A 1‐month‐old female infant presented with extensive segmental hemangiomas on the left lower extremity, left perineum and gluteal region with ulceration. Bilateral labia minoras were asymmetrical. Both legs were asymmetrical with left leg atrophy, and the intergluteal cleft was deviated. A dark red pustule and a sacrococcygeal dimple could be seen in the lumbosacral region. Lipomyelomeningocele, tethered cord and sacrum dysplasia were noted by magnetic resonance imaging. The patient was found to have an absent left kidney at 32 weeks of pregnancy. Eventually, we draw the diagnosis of LUMBAR syndrome. In addition, we discuss the clinical manifestation, diagnosis, treatment and pathogenesis by a review of published work.