Seaweed Porphyra yezoensis polysaccharides with different molecular weights inhibit hydroxyapatite damage and osteoblast differentiation of A7R5 cells.

Vascular calcification (VC) is a common pathological manifestation in patients with cardiovascular diseases, leading to high mortality in patients with chronic kidney diseases. The deposition of hydroxyapatite (HAP) crystals on vascular smooth muscle cells leads to cell damage, which promotes osteogenic transformation. In this study, four different molecular weights (MWs ) of Porphyra yezoensis polysaccharides (PYP1, PYP2, PYP3, and PYP4 with MWs of 576, 49.5, 12.6, and 4.02 kDa, respectively) were used to coat HAP, and the differences in toxicity and calcification of HAP on A7R5 cells before and after coating were studied. The results showed that PYPs could effectively reduce HAP damage to the A7R5 cells. Under the protection of PYPs, cell viability increased and lactate dehydrogenase release, active oxygen level, and cell necrosis rate decreased; also, the amount of the HAP crystals adhering to cell surfaces and entering cells decreased. PYPs with low molecular weights presented better protective effects than high-molecular-weight PYPs. PYPs also inhibited the osteogenic transformation of the A7R5 cells induced by HAP and decreased alkaline phosphatase (ALP) activity and expressions of bone/chondrocyte phenotype genes (runt-related factor 2, ALP, osteopontin, and osteocalcin). In the adenine-induced chronic renal failure (CRF) mouse VC model, PYP4 was found to obviously inhibit the aortic calcium level, and it also inhibited the serum creatinine, serum phosphorus and serum BUN levels. PYP4 (least molecular weight) showed the best inhibitory effect on calcification and may be considered as a candidate drug with therapeutic potential for inhibiting cellular damage and osteoblast differentiation induced by the HAP crystals.

Tanshinone IIA attenuates high glucose induced human VSMC proliferation and migration through miR-21-5p-mediated tropomyosin 1 downregulation.

The proliferation and migration of vascular smooth muscle cells (VSMCs) play important roles in the development and progression of diabetes-related vascular complications. Recently, microRNAs (miRNAs) have been suggested to be involved in the pathogenesis of vascular diseases. This study was designed to investigate the influences of tanshinone IIA, an active compound extracted from Chinese herb Salvia miltiorrhiza, on the proliferation and migration of human aortic VSMCs (HASMCs). cultured in a high glucose medium and the underlying mechanisms related miRNAs. Using a miRNA microarray method, we profiled the miRNA expression signature in human aortic VSMCs (HASMCs) exposed to normal glucose, high glucose with and without Tanshinone IIA. Cell proliferation was measured with 5-bromo-2'-deoxyuridine (BrdU) incorporation assay. Cell migration was evaluated using transwell migration assay and wound scratch assay. Western blot was used to examine the expression of tropomyosin 1 (TPM1) and miRNA level was quantified by real-time PCR. The results showed that several miRNAs that were highly expressed in the high glucose group were significantly decreased in the high glucose with Tanshinone IIA group compared with the normal glucose group (P < 0.05). Among these miRNAs, miR-21-5p was significantly upregulated in the high glucose group and downregulated after Tanshinone IIA treatment (P < 0.05). The depletion of miR-21-5p in HASMCs resulted in decreased cell proliferation and migration (P < 0.05). Moreover, we found that Tanshinone IIA inhibited proliferation and migration partly through miR-21-5p-mediated TPM1 downregulation (P < 0.05). In conclusion, the present study demonstrates that Tanshinone IIA is able to protect HASMCs from high glucose-induced proliferation and migration through regulating expression of miRNAs.

Contraction-dependent TGF-ß1 activation is required for thrombin-induced remodeling in human airway smooth muscle cells.

AIMS: Thrombin is a serine proteinase that is not only involved in coagulation cascade, but also mediates a number of biological responses relevant to tissues repair, and induces bronchoconstriction. TGF-ß plays a pivotal role in airway remodeling due to its effects on airway smooth muscle proliferation and extracellular matrix (ECM) deposition. Recently, bronchoconstriction itself is found to constitute a form of strain and is highly relevant to asthmatic airway remodeling. However, the underlying mechanisms remain unknown. Here, we investigated the role of contraction- dependent TGF-ß activation in thrombin-induced remodeling in human airway smooth muscle (HASM) cells. MATERIALS AND METHODS: Primary HASM cells were treated with or without thrombin in the absence or presence of anti-TGF-ß antibody, cytochalasin D and formoterol. CFSE labeling index or CCK-8 assay were performed to test cell proliferation. RT-PCR and Western blotting were used to examined ECM mRNA level and collagen Iα1, α-actin protein expression, respectively. Immunofluorescence was also used to confirm contraction induced by thrombin in HASM cells. KEY FINDING: Thrombin stimulation enhanced HASM cells proliferation and activated TGF-ß signaling. Thrombin induced ECM mRNA and collagen Iα1 protein expression, and these effects are mediated by TGF-ß. Abrogation of TGF-ß activation by contraction inhibitors cytochalasin D and formoterol prevents the thrombin-induced effects. SIGNIFICANCE: These findings suggest that contraction-dependent TGF-ß activation could be a mechanism by which thrombin leads to the development of asthmatic airway remodeling. Blocking physical forces with bronchodilator would be an intriguing way in reducing airway remodeling in asthma.

Eukaryotic initiation factor 6 modulates myofibroblast differentiation at transforming growth factor-ß1 transcription level via H2A.Z occupancy and Sp1 recruitment.

Eukaryotic initiation factor 6 (eIF6) is a pivotal regulator of ribosomal function, participating in translational control. Previously our data suggested that eIF6 acts as a key binding protein of P311 (a hypertrophic scar-related protein; also known as NREP). However, a comprehensive investigation of its functional role and the underlying mechanisms in modulation of myofibroblast (a key effector of hypertrophic scar formation) differentiation remains unclear. Here, we identified that eIF6 is a novel regulator of transforming growth factor-ß1 (TGF-ß1) expression at transcription level, which plays a key role in myofibroblast differentiation. Mechanistically, this effect is associated with eIF6 altering the occupancy of the TGF-ß1 promoter by H2A.Z (Swiss-Prot P0C0S6) and Sp1. Accordingly, modulation of eIF6 expression in myofibroblasts significantly affects their differentiation via the TGF-ß/Smad signaling pathway, which was verified in vivo by the observation that heterozygote eIF6(+/-) mice exhibited enhanced TGF-ß1 production coupled with increased α-smooth muscle actin (α-SMA)(+) myofibroblasts after skin injury. Overall, our data reveal a novel transcriptional regulatory mechanism of eIF6 that acts on facilitating Sp1 recruitment to TGF-ß1 promoter via H2A.Z depletion and thus results in increased TGF-ß1 transcription, which contributes to myofibroblast differentiation.

[Effects of P 311 on the migration of epidermal stem cells in mice with superficial partial-thickness burn and injured cell model in vitro].

OBJECTIVE: To study effects of P311 on the migration of epidermal stem cells (ESCs) in mice with superficial partial-thickness burn and injured cell model in vitro and to explore the mechanism. METHODS: (1) Eighteen male C(57) BL/6 mice were used. Fifteen of them were inflicted with superficial partial-thickness burn on the back. In three injured mice wound tissue and skin of wound edge were obtained at post burn hour (PBH) 6, 12, 24, 48, 72 respectively. The rest three mice were used as normal control, and samples were harvested with the same method as above. The expressions of P311 in harvested samples were assessed with biotin-streptavidin-peroxidase (SP) staining. (2) Six newly born C(57) BL/6 mice were intraperitoneally injected with 50 µg/g BrdU (two times a day) for three days for ESCs-labelling. Seven weeks later, the mice were inflicted with superficial partial-thickness burn on the back. Serial slices of burn wound tissue were prepared at PBH 72 and immunohistochemically stained with SP for observation of the co-localization of BrdU-positive ESCs and P311-positive cells. (3) The empty vector pAdEasy-enhanced green fluorescence protein (EGFP) and the adenovirus P311-expressing vector named pAdEasy-EGFP-P311 were constructed and packed. Human ESCs were isolated by the method of rapid adhesion to collagen IV. After being divided into P311 high-expressing group (n = 3) and EGFP control group (n = 3), the ESCs in two groups were respectively infected by pAdEasy-EGFP-P311 and pAdEasy-EGFP. Scratching assay was performed on ESCs in both groups after they were treated by mitomycin C for 2 hours. The remaining area within the fixed range was measured at post scratching hour (PSH) 0, 24, 48, and 72, and the wound-area healing rate was calculated. Data were processed with independent samples t test. RESULTS: (1) Expression amount of P311 was different in different parts of wound at different time points after burn. Expression amount of P311 in the newly formed epidermis and hair follicle of wound increased along with prolongation of time. Expression amount of P311 in the epidermis and hair follicle of wound edge peaked at PBH 12 and then decreased to normal levels at PBH 72. (2) Co-localization of BrdU-positive ESCs and P311-positive cells was observed in the new epidermal layer of wound tissue of mice, where ESCs were labeled by BrdU. (3) At PSH 48 and 72, wound-area healing rate was obviously higher in P311 high-expressing group [(69 ± 31)%, (89 ± 26)%] than in EGFP control group [(35 ± 12)%, (46 ± 31)%, with t values respectively -2.336, -2.611, P values all below 0.05]. CONCLUSIONS: P311 may promote the migration of ESCs both in rats with superficial partial-thickness burns and in injured cell model in vitro, and it may play an important role in wound healing.

[Biologic effect of nitric oxide on human epidermal stem cells in vitro].

OBJECTIVE: To observe the effect of nitric oxide (NO) on adhesion, proliferation, and migration of human epidermal stem cells (ESC) in vitro. METHODS: ESC were isolated and cultured by the modified method of rapid attachment to type IV collagen. (1) Morphology of cells was observed under inverted phase-contrast microscope. Expression levels of integrin ß(1) and cytokeratin 19 (CK19) of cells were determined by Western blotting and immunofluorescence staining. (2) After being treated with scratching, ESC adhered to the wall was respectively treated with nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) in the concentration of 1, 10, 100, 500 µmol/L. ESC without treatment of SNAP was used as control. The migration rate of ESC was detected at post scratching hour (PSH) 12 and 24. The chemotaxis of ESC (treated with SNAP in above-mentioned concentration) was tested by Transwell assay, and the transferred cell number was counted. (3) ESC was respectively treated with SNAP in the concentration of 10, 100, 500 µmol/L for 1 h. ESC without treatment of SNAP was used as control. The adhesion of ESC was detected with adhesion test, and the inhibition rate of adhesion was calculated. The proliferation of ESC (denoted as absorbance value) was determined by microplate reader at post-treatment hour (PTH) 0, 12, 24, 48. Data were processed with one-way analysis of variance and Dunnett t test. RESULTS: (1) Small clone formed on post culture days (PCD) 5 to 9. On PCD 10 to 14, cell proliferation sped up. CK19 and integrin ß(1) were detected to be expressed in the isolated cells. The cells were identified as ESC. (2) Compared with that of ESC without treatment of SNAP [(35.7 ± 0.3)%, (45.7 ± 5.0)%], migration of ESC treated with SNAP in the concentration from 1 to 100 µmol/L was promoted at PSH 12 and 24. Migration rates of ESC treated with 100 µmol/L SNAP were the highest [respectively (48.8 ± 2.7)%, (82.1 ± 15.8)%, with t value respectively 8.34, 5.10, P values both below 0.01]. The number of ESC transferred to membrane after being treated with 100 µmol/L SNAP was significantly larger than that of ESC without treatment of SNAP (t = 9.24, P = 0.00). (3) Absorbance values of ESC treated with 100, 500 µmol/L SNAP were obviously higher than that of ESC without treatment of SNAP (with t value respectively 4.30, 4.67, P values both equal to 0.00). Proliferation of ESC treated with 100, 500 µmol/L SNAP was obviously stronger than that of cells without treatment of SNAP at PTH 24, 48 (with t values from 2.84 to 8.17, P values all below 0.05). CONCLUSIONS: Exogenous NO in suitable concentration can promote the migration of human ESC. Exogenous NO can inhibit the adhesion and promote the proliferation of human ESC in vitro.

[Molecular characterization of hantavirus Shandong isolate JNL virus strain].

OBJECTIVE: To understand the molecular epidemiologic characteristics of hantavirus Shandong isolate JNL virus strain. METHODS: The complete M and S gene of the JNL virus isolated from Shandong Province was amplified by RT- PCR, and the purified PCR product was cloned into T vector for sequencing. RESULTS: The results revealed that the JNL M segment was 3615 bp in length, encoding 1135 amino acids, and the S segment was 1698 bp encoding 429 amino acids, JNL belongs to HTN virus. The comparison of homology with HTN and SEO types showed that the difference of M and S complete sequences between JNL and all other HTN virus strains reached 20.0%-20.6%, and 15.5%-16.0%, respectively. Phylogenetic tree also showed that the position of JNL is located at a different clade. CONCLUSIONS: HTN virus Shandong local isolate JNL strain is a new specific HTN subtype virus.