LncPTSR Triggers Vascular Remodeling in Pulmonary Hypertension by Regulating [Ca2+]i in Pulmonary Arterial Smooth Muscle Cells.

Pulmonary hypertension (PH) is characterized by vascular remodeling and sustained increase in right ventricular systolic pressure. The molecular mechanisms behind PH development remain unclear. Here, a long noncoding RNA (lncRNA) attenuated by platelet-derived growth factor BB (PDGF-BB) was identified, and its functional roles were investigated in vitro and in vivo. Using RNA-sequencing data and rapid amplification of cDNA ends, an lncRNA neighboring the locus of ATPase plasma membrane Ca2+ transporting 4 (PMCA4) was identified and named lncPTSR. It is a highly conserved nuclear lncRNA and was downregulated in pulmonary arterial smooth muscle cells (PASMCs) with PDGF-BB stimulation or hypoxia induction. Gene interruption or overexpression assays revealed that lncPTSR negatively regulates rat PASMC proliferation, apoptosis, and migration. LncPTSR interruption in Sprague Dawley rats using adeno-associated virus type 9-mediated shRNA resulted in a significant increase in right ventricular systolic pressure and vascular remodeling in normoxic condition. LncPTSR knockdown also suppressed PMCA4 expression and attenuated the intracellular Ca2 + efflux of PASMCs in vitro and in vivo. Further studies suggest a complex crosstalk between lncPTSR and mitogen-activated protein kinase pathway: inhibition of mitogen-activated protein kinase kinase and extracellular signal-regulated kinase abolishes the PDGF-BB-mediated lncPTSR downregulation, and lncPTSR plays a feedback regulation for mitogen-activated protein kinase-signaling molecules. The present study suggests that lncPTSR participates in pulmonary artery remodeling via modulating the expression of PMCA4 and intracellular Ca2 + homeostasis downstream of PDGF-BB-driven mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling. These results suggest that lncPTSR may be a promising therapeutic target in PH treatment.

PDGF/MEK/ERK axis represses Ca2+ clearance via decreasing the abundance of plasma membrane Ca2+ pump PMCA4 in pulmonary arterial smooth muscle cells.

Pulmonary arterial hypertension (PAH) is a rare and lethal disease characterized by vascular remodeling and vasoconstriction, which is associated with increased intracellular calcium ion concentration ([Ca2+]i). Platelet-derived growth factor-BB (PDGF-BB) is the most potent mitogen for pulmonary arterial smooth muscle cells (PASMCs) and is involved in vascular remodeling during PAH development. PDGF signaling has been proved to participate in maintaining Ca2+ homeostasis of PASMCs; however, the mechanism needs to be further elucidated. Here, we illuminate that the expression of plasma membrane calcium-transporting ATPase 4 (PMCA4) was downregulated in PASMCs after PDGF-BB stimulation, which could be abolished by restraining the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK). Functionally, suppression of PMCA4 attenuated the [Ca2+]i clearance in PASMCs after Ca2+ entry, promoting cell proliferation and elevating cell locomotion through mediating formation of focal adhesion. Additionally, the expression of PMCA4 was decreased in the pulmonary artery of monocrotaline (MCT)- or hypoxia-induced PAH rats. Moreover, knockdown of PMCA4 could increase the right ventricular systolic pressure (RVSP) and wall thickness (WT) of pulmonary artery in rats raised under normal conditions. Taken together, our findings demonstrate the importance of the PDGF/MEK/ERK/PMCA4 axis in intracellular Ca2+ homeostasis in PASMCs, indicating a functional role of PMCA4 in pulmonary arterial remodeling and PAH development.

The activated CD36-Src axis promotes lung adenocarcinoma cell proliferation and actin remodeling-involved metastasis in high-fat environment.

Obesity/overweight and lipid metabolism disorders have become increased risk factors for lung cancer. Fatty acid translocase CD36 promotes cellular uptake of fatty acids. Whether and how CD36 facilitates lung adenocarcinoma (LUAD) growth in high-fat environment is unknown. Here, we demonstrated that palmitic acid (PA) or high-fat diet (HFD) promoted LUAD cell proliferation and metastasis in a CD36-dependent manner. Mechanistically, CD36 translocated from cytoplasm to cell membrane and interacted with Src kinase upon PA stimulation in human LUAD cells. Akt and ERK, downstream of Src, were then activated to mediate LUAD cell proliferation and metastasis. Furthermore, PA treatment promoted CD36 sarcolemmal translocation, where it activated Rac1 and upregulated MMP-9 through Src-Akt/ERK pathway, resulting in redistribution of cortactin, N-WASP and Arp2/3, and finally led to occurrence of finger-like protrusions of actin on cell surface to enhance cell metastasis. Compared with normal-chew diet (NCD) mice, the HFD group exhibited higher level of blood free fatty acid (FFA) and cholesterol (TC), developed larger xenograft LUAD tumors and enhanced tumor cell metastatic potential, which were accompanied by obvious sarcolemmal actin remodeling and were blocked by simultaneous CD36 knockdown in LUAD cells. Consistently, xenografted and tail vein-injected scramble-RNA-A549 cells but not CD36-shRNA-A549 in HFD mice formed metastatic LUAD tumors on the lung. CD36 inhibitor SSO significantly inhibited LUAD cell metastasis to the lung. Collectively, CD36 initiates Src signaling to promote LUAD cell proliferation and actin remodeling-involved metastasis under high-fat environment. Our study provides the new insights that CD36 is a valid target for LUAD therapy.

Downregulation of mTORC1 and Mcl-1 by lipid-oversupply contributes to islet ß-cell apoptosis and dysfunction.

Pancreatic ß-cell apoptosis is a key feature of diabetes and can be induced by chronic exposure to saturated fatty acids (FAs). However, the underlying mechanisms remain poorly understood. We presently evaluated the role of Mcl-1 and mTOR in mice fed with high-fat-diet (HFD) and ß-cells exposed to the overloaded palmitic acid (PA). Compared with normal-chow-diet (NCD)-fed mice, HFD group showed impaired glucose tolerance after two months. Along with the diabetes progression, pancreatic islets first became hypertrophic and then atrophic, the ratio of ß-cell:α-cell increased in the islets of four months HFD-fed mice while decreased after six months. This process was accompanied by significantly increased ß-cell apoptosis and AMPK activity, and decreased Mcl-1 expression and mTOR activity. Consistently, glucose-induced insulin secretion dropped. In terms of mechanism, PA with lipotoxic dose could activate AMPK, which in turn inhibited ERK-stimulated Mcl-1Thr163 phosphorylation. Meanwhile, AMPK blocked Akt activity to release Akt inhibition on GSK3ß, followed by GSK3ß-initiated Mcl-1Ser159 phosphorylation. The context of Mcl-1 phosphorylation finally led to its degradation by ubiquitination. Also, AMPK inhibited the activity of mTORC1, resulting in a lower level of Mcl-1. Suppression of mTORC1 activity and Mcl-1 expression positively related to ß-cell failure. Alteration of Mcl-1 or mTOR expression rendered different tolerance of ß-cell to different dose of PA. In conclusion, lipid oversupply-induced dual modulation of mTORC1 and Mcl-1 finally led to ß-cell apoptosis and impaired insulin secretion. The study may help further understand the pathogenesis of ß-cell dysfunction in case of dyslipidemia, and provide promising therapeutic targets for diabetes.

Targeting CD36 determines nicotine derivative NNK-induced lung adenocarcinoma carcinogenesis.

Smoking carcinogen nicotine-derived nitrosamine ketone (NNK) is the most potent contributor to lung adenocarcinoma (LUAD) development, but the mechanism has not been fully elucidated. Here, we reported that fatty acid translocase CD36 was significantly overexpressed in both human LUAD tissues and NNK-induced A/J mice LUAD tumors. The overexpressed CD36 was positively correlated with Src kinase activation, smoking status, metastasis, and worse overall survival of patients with smoking history. Upon NNK binding with α7 nicotinic acetylcholine receptor (α7nAChR), sarcolemmal CD36 was increased and it interacted with surface α7nAChR and cytosol Src simultaneously, which in turn activated Src and downstream pro-carcinogenic kinase ERK1/2 and Akt, and finally caused LUAD cells to form subcutaneous and pulmonary metastatic tumors. This process could be blocked by CD36 knockdown and CD36 irreversible inhibitor SSO. Furthermore, the effect of NNK was inhibited obviously in CD36-/- A/J mice. Thus, targeting CD36 may provide a breakthrough therapy of LUAD.

Biofilm stratification in counter-diffused membrane biofilm bioreactors (MBfRs) for aerobic methane oxidation coupled to aerobic/anoxic denitrification: Effect of oxygen pressure.

Aerobic methane oxidation coupled with denitrification (AME-D) executed in membrane biofilm bioreactors (MBfRs) provides a high promise for simultaneously mitigating methane (CH4) emissions and removing nitrate in wastewater. However, systematically experimental investigation on how oxygen partial pressure affects the development and characteristics of counter-diffusional biofilm, as well as its spatial stratification profiles, and the cooperative interaction of the biofilm microbes, is still absent. In this study, we combined Optical Coherence Tomography (OCT) with Confocal Laser Scanning Microscopy (CLSM) to in-situ characterize the development of counter-diffusion biofilm in the MBfR for the first time. It was revealed that oxygen partial pressure onto the MBfR was capable of manipulating biofilm thickness and spatial stratification, and then managing the distribution of functional microbes. With the optimized oxygen partial pressure of 5.5 psig (25% oxygen content), the manipulated counter-diffusional biofilm in the AME-D process obtained the highest denitrification efficiency, due mainly to that this biofilm had the proper dynamic balance between the aerobic-layer and anoxic-layer where suitable O2 gradient and sufficient aerobic methanotrophs were achieved in aerobic-layer to favor methane oxidation, and complete O2 depletion and accessible organic sources were kept to avoid constraining denitrification activity in anoxic-layer. By using metagenome analysis and Fluorescence in situ hybridization (FISH) staining, the spatial distribution of the functional microbes within counter-diffused biofilm was successfully evidenced, and Rhodocyclaceae, one typical aerobic denitrifier, was found to survive and gradually enriched in the aerobic layer and played a key role in denitrification aerobically. This in-situ biofilm visualization and characterization evidenced directly for the first time the cooperative path of denitrification for AME-D in the counter-diffused biofilm, which involved aerobic methanotrophs, heterotrophic aerobic denitrifiers, and heterotrophic anoxic denitrifiers.

Therapeutic effects of CXCR4+ subpopulation of transgene-free induced cardiosphere-derived cells on experimental myocardial infarction.

OBJECTIVES: Myocardial infarction (MI) is the most predominant type of cardiovascular diseases with high mortality and morbidity. Stem cell therapy, especially cardiac progenitor cell therapy, has been proposed as a promising approach for cardiac regeneration and MI treatment. Previously, we have successfully generated cardiac progenitor-like cells, induced cardiosphere (iCS), via somatic reprogramming. However, the genome integration characteristic of virus-based reprogramming approach hampered their therapeutic applications due to the risk of tumour formation. In the current study, we aim to establish a safer iCS generation strategy with transgene-free approaches. MATERIALS AND METHODS: Four transgene-free approaches for somatic reprogramming, including episome, minicircle, self-replicative RNA, and sendai virus, were compared, from the perspective of cardiac progenitor marker expression, iCS formation, and cardiac differentiation. The therapeutic effects were assessed in the mouse model of MI, from the perspective of survival rate, cardiac function, and structural alterations. RESULTS: The self-replicative RNA approach produced more iCS, which had cardiomyocyte differentiation ability and therapeutic effects on the mouse model of MI with comparable levels with endogenous cardiospheres and iCS generated with retrovirus. In addition, the CXCR4 (C-X-C chemokine receptor 4) positive subpopulation of iCS derived cells (iCSDC) delivered by intravenous injection was found to have similar therapeutic effects with intramyocardial injection on the mouse model of MI, representing a safer delivery approach. CONCLUSION: Thus, the optimized strategy for iCS generation is safer and has more therapeutic potentials.

Neuroprotective Effects of Ginsenoside Rg1 against Hyperphosphorylated Tau-Induced Diabetic Retinal Neurodegeneration via Activation of IRS-1/Akt/GSK3ß Signaling.

We have recently demonstrated that tau hyperphosphorylation causes diabetic synaptic neurodegeneration of retinal ganglion cells (RGCs), which might be the earliest affair during the pathogenesis of diabetic retinopathy (DR). Thus, there is a pressing need to seek therapeutic agents possessing neuroprotective effects against tau hyperphosphorylation in RGCs for arresting the progression of DR. Here, using a well-characterized diabetes model of db/db mouse, we discovered that topical ocular application of 10 mg/kg/day of ginsenoside Rg1 (GRg1), one of the major active ingredients extracted from Panax ginseng and Panax notoginseng, ameliorated hyperphosphorylated tau-triggered RGCs synaptic neurodegeneration in diabetic mice. The neuroprotective effects of GRg1 on diabetic retinae were abrogated when retinal IRS-1 or Akt was suppressed by intravitreal injection with si-IRS-1 or topically coadministered with a specific inhibitor of Akt, respectively. However, selective repression of retinal GSK3ß by intravitreal administration of si-GSK3ß rescued the neuroprotective properties of GRg1 when Akt was inactivated. Therefore, the present study showed for the first time that GRg1 can prevent hyperphosphorylated tau-induced synaptic neurodegeneration of RGCs via activation of IRS-1/Akt/GSK3ß signaling in the early phase of DR. Moreover, our data clarify the potential therapeutic significance of GRg1 for neuroprotective intervention strategies of DR.

[Establishment of the human papillomavirus type 31 positive cervical cancer cell line].

The establishment of in vitro model will provide optimal conditions for the study of human papillomavirus (HPV)-associated cervical cancer. In this study, E6 and E7 gens of HPV31 were cloned and expressed in E. coli. The recombinant proteins were purified and used as antigens to immunize mice for the production of polyclonal antibody. Mammalian expression plasmid pBudCE4. 1-HPV31-E6/E7 was also constructed and transfected into C33A cells. The transfected cells were then selected by Zeocin. The expressions of the E6 and E7 mRNAs and proteins were detected by RT-PCR and Western blot respectively. A stable cervical cancer cell line was established as an in vitro model for the study of human papillomavirus type 31(HPV31) associated cervical cancer.

[Expression, purification and antigenicity of P35 gene of Toxoplasma gondii].

OBJECTIVE: P35 is an important surface protein for Toxoplasma gondii. To obtain the highly pure and specific antigenicity protein, the gene P35 was cloned and its product was expressed in E. coli Rosetta. The expressed protein was purified and its immunogenecity was studied. METHODS: A pair of primers was designed according to cDNA sequence of P35, and then the P35 gene amplified by PCR was cloned into the vector pGEM-T and proved by DNA sequencing. The P35 gene was subcloned into prokaryotic expression vector pET-KDO, its expression was induced by IPTG, and the target protein was obtained by affinity chromatography. RESULTS: The P35 gene was successfully amplified from genome DNA of Toxoplasma gondii RH strain and a fusion protein was expressed in E. coli. The molecular weight of the expressed protein was about Mr 42 000. Western blotting indicated that the antigenicity of the protein was specific. CONCLUSIONS: The plasmid pET-KDO-p35 is constructed and the high efficient expression of P35 fusion protein has been achieved in E. coli. The fusion protein shows a specific antigenicity, the P35 fusion protein has a potential value in the diagnosis of toxoplasmosis.

[Expression of porcine beta-defensin 1 gene in Pichia pastoris].

PBD-1 is an antibacterial peptide that plays an important role in defence system of porcine. To produce PBD-1 with bioactivity in Pichia pastoris, according to published amino acid sequence of porcine beta-defensin 1(PBD-1) and the partiality codon of yeast, the PBD-1 gene was synthesized by PCR and cloned into pPIC9K to construct the recombinant expression vector pPIC9K-PBD-1, the obtained recombinant plasmid was linearized by Sal I, and then transformed into SMD1168 by electroporation. Under the control of the promoter AOX1, an approximately 4.5 kD PBD-1 peptide was expressed. Antibacterial activity assay shows that the PBD-1 has the antibacterial activity on Staphylococcus aureus. This is the first secreted expression of porcine beta-defensin 1 gene in Pichia pastoris.