The Effect of Electronic-Cigarette Vaping on Cardiac Function and Angiogenesis in Mice.

The rapid increase in use of electronic-cigarettes (e-cigarettes), especially among youth, raises the urgency for regulating bodies to make informed decisions, guidance, and policy on these products. This study evaluated cardiac function in an experimental model following exposure to e-cigarettes. We subjected C57BL/6 mice to e-cigarette vaping for 2-weeks, and cardiac function was assessed using echocardiography. Cardiac tissues were collected at the end of e-cigarette exposure for pathological analysis. The experimental data showed that e-cigarette vaping (3 h/day for 14 days) had no significant effect on cardiac contractility as measured by ejection fraction. However, it significantly increased angiogenesis in mouse heart tissue. We found that e-cigarette exposure increased the endothelial cell marker CD31 and CD34 to approximately 2 fold (p < 0.05) in heart tissue from female mice and about 150% (p < 0.05) in male mice. E-cigarette vaping also caused slower weight gain compared to mice exposed to room air. In addition, short-term e-cigarette exposure slightly increased collagen content in heart tissue but did not result in significant tissue fibrosis. These results suggest that short-term exposure to e-cigarettes has no acute effect on cardiac contractile function or tissue fibrosis, but it increases cardiac angiogenesis.

Characterization of a Long Non-Coding RNA, the Antisense RNA of Na/K-ATPase α1 in Human Kidney Cells.

Non-coding RNAs are important regulators of protein-coding genes. The current study characterized an antisense long non-coding RNA, ATP1A1-AS1, which is located on the opposite strand of the Na/K-ATPase α1 gene. Our results show that four splice variants are expressed in human adult kidney cells (HK2 cells) and embryonic kidney cells (HEK293 cells). These variants can be detected in both cytosol and nuclear fractions. We also found that the inhibition of DNA methylation has a differential effect on the expression of ATP1A1-AS1 and its sense gene. To investigate the physiological role of this antisense gene, we overexpressed the ATP1A1-AS1 transcripts, and examined their effect on Na/K-ATPase expression and related signaling function in human kidney cells. The results showed that overexpression of the ATP1A1-AS1-203 transcript in HK2 cells reduced the Na/K-ATPase α1 (ATP1A1) gene expression by approximately 20% (p < 0.05), while reducing the Na/K-ATPase α1 protein synthesis by approximately 22% (p < 0.05). Importantly, overexpression of the antisense RNA transcript attenuated ouabain-induced Src activation in HK2 cells. It also inhibited the cell proliferation and potentiated ouabain-induced cell death. These results demonstrate that the ATP1A1-AS1 gene is a moderate negative regulator of Na/K-ATPase α1, and can modulate Na/K-ATPase-related signaling pathways in human kidney cells.

Hiding inside? Intracellular expression of non-glycosylated c-kit protein in cardiac progenitor cells.

Cardiac progenitor cells including c-kit(+) cells and cardiosphere-derived cells (CDCs) play important roles in cardiac repair and regeneration. CDCs were reported to contain only small subpopulations of c-kit(+) cells and recent publications suggested that depletion of the c-kit(+) subpopulation of cells has no effect on regenerative properties of CDCs. However, our current study showed that the vast majority of CDCs from murine heart actually express c-kit, albeit, in an intracellular and non-glycosylated form. Immunostaining and flow cytometry showed that the fluorescent signal indicative of c-kit immunostaining significantly increased when cell membranes were permeabilized. Western blots further demonstrated that glycosylation of c-kit was increased during endothelial differentiation in a time dependent manner. Glycosylation inhibition by 1-deoxymannojirimycin hydrochloride (1-DMM) blocked c-kit glycosylation and reduced expression of endothelial cell markers such as Flk-1 and CD31 during differentiation. Pretreatment of these cells with a c-kit kinase inhibitor (imatinib mesylate) also attenuated Flk-1 and CD31 expression. These results suggest that c-kit glycosylation and its kinase activity are likely needed for these cells to differentiate into an endothelial lineage. In vivo, we found that intracellular c-kit expressing cells are located in the wall of cardiac blood vessels in mice subjected to myocardial infarction. In summary, our work demonstrated for the first time that c-kit is not only expressed in CDCs but may also directly participate in CDC differentiation into an endothelial lineage.

Na/K-ATPase signaling regulates collagen synthesis through microRNA-29b-3p in cardiac fibroblasts.

Chronic kidney disease (CKD) is accompanied by cardiac fibrosis, hypertrophy, and dysfunction, which are commonly referred to as uremic cardiomyopathy. Our previous studies found that Na/K-ATPase ligands or 5/6th partial nephrectomy (PNx) induces cardiac fibrosis in rats and mice. The current study used in vitro and in vivo models to explore novel roles for microRNA in this mechanism of cardiac fibrosis formation. To accomplish this, we performed microRNA profiling with RT-qPCR based arrays on cardiac tissue from rats subjected to marinobufagenin (MBG) infusion or PNx. The analysis showed that a series of fibrosis-related microRNAs were dysregulated. Among the dysregulated microRNAs, microRNA (miR)-29b-3p, which directly targets mRNA of collagen, was consistently reduced in both PNx and MBG-infused animals. In vitro experiments demonstrated that treatment of primary cultures of adult rat cardiac fibroblasts with Na/K-ATPase ligands induced significant increases in the fibrosis marker, collagen protein, and mRNA expression compared with controls, whereas miR-29b-3p expression decreased >50%. Transfection of miR-29b-3p mimics into cardiac fibroblasts inhibited cardiotonic steroids-induced collagen synthesis. Moreover, a specific Na/K-ATPase signaling antagonist, pNaKtide, prevented ouabain-induced increases in collagen synthesis and decreases in miR-29b-3p expression in these cells. In conclusion, these data are the first to indicate that signaling through Na/K-ATPase regulates miRNAs and specifically, miR-29b-3p expression both in vivo and in vitro. Additionally, these data indicate that miR-29b-3p expression plays an important role in the formation of cardiac fibrosis in CKD.

Characterizing intermediates along the transition from polyproline I to polyproline II using ion mobility spectrometry-mass spectrometry.

Polyproline exists predominately as the all-cis polyproline I (PPI) helix in aliphatic alcohols, whereas the all-trans polyproline II (PPII) helix is favored in aqueous solutions. Previous ion mobility spectrometry-mass spectrometry (IMS-MS) work demonstrates that the gas-phase conformations of polyproline ions can be related to the corresponding PPI and PPII helices in solution [J. Phys. Chem. B 2004, 108, 4885]. Here, we use IMS-MS to examine the detailed intermediate steps associated with the process of Polyproline-13 (Pro13) conversion from the PPI helix to the PPII helix upon solvent exchange. Collision cross section distributions of Pro13 [M + 2H](2+) ions obtained at different transition times indicate the presence of two major conformers, identified as the PPI and PPII helices, and six conformers that appear as subpopulations of polyproline. Further analysis shows a transition mechanism with sequential cis-trans isomerizations followed by a parallel process to establish PPII and two smaller subpopulations at equilibrium. Temperature-dependent studies are used to obtain Arrhenius activation parameters for each step of the mechanism, and molecular dynamics simulations provide insight about the structures of the intermediates. It appears that prolines sequentially flip from cis to trans starting from the N-terminus. However, after the first few transitions, possible steps take place at the center of the peptide chain; subsequently, several pathways appear to be accessible at the same time. Our results reflect the existence of stable subpopulations in polyprolines and provide new insight into the structural changes during the transition process of polyproline peptides converting from PPI to PPII in aqueous solution.

Reduction of Na/K-ATPase affects cardiac remodeling and increases c-kit cell abundance in partial nephrectomized mice.

The current study examined the role of Na/K-ATPase α1-subunit in animals subjected to 5/6th partial nephrectomy (PNx) using Na/K-ATPase α1-heterozygous (α1(+/-)) mice and their wild-type (WT) littermates. After PNx, both WT and α1(+/-) animals displayed diastolic dimension increases, increased blood pressure, and increased cardiac hypertrophy. However, in the α1(+/-) animals we detected significant increases in cardiac cell death in PNx animals. Given that reduction of α1 elicited increased cardiac cell death with PNx, while at the same time these animals developed cardiac hypertrophy, an examination of cardiac cell number, and proliferative capabilities of those cells was carried out. Cardiac tissues were probed for the progenitor cell marker c-kit and the proliferation marker ki-67. The results revealed that α1(+/-) mice had significantly higher numbers of c-kit-positive and ki-67-positive cells, especially in the PNx group. We also found that α1(+/-) mice express higher levels of stem cell factor, a c-kit ligand, in their heart tissue and had higher circulating levels of stem cell factor than WT animals. In addition, PNx induced significant enlargement of cardiac myocytes in WT mice but has much less effect in α1(+/-) mice. However, the total cell number determined by nuclear counting is higher in α1(+/-) mice with PNx compared with WT mice. We conclude that PNx induces hypertrophic growth and high blood pressure regardless of Na/K-ATPase content change. However, total cardiac cell number as well as c-kit-positive cell number is increased in α1(+/-) mice with PNx.

[Abnormally lower expression of cmtm5 gene in bone marrow cells from patients with multiple myeloma].

This study was aimed to detect the expression level of cmtm 5 (CKLF-like MARVEL transmembrane domain containing member 5) gene in the bone marrow cells from patients with multiple myeloma (MM), and to investigate the correlation between the expression level of cmtm5 and various clinical characteristics. Real-time quantitative reverse transcription polymerase chain reaction (RQ-RT-PCR) was used to measure the expression levels of cmtm5 gene in the bone marrow cells collected from MM patients, and the MM cell lines, namely, RPMI8226 and CZ1 cells. The normal donor marrow specimens were used as the reference. The ratio of cmtm5 copy number to abl (Abelson murine leukemia viral oncogene homolog) gene copy number was used for indicating the expression level. The results showed that the expression level of cmtm5 gene was significantly down-regulated in bone marrow cells of 51 untreated or relapsed/refractory MM patient as compared to those of normal donor marrow cells (0.047+/-0.062 for the untreated or relapsed/refractory MM patients versus 0.255+/-0.333 for the normal, p<0.01). According to the International Staging System (ISS), the cmtm5 expression level in marrow cells of patients in ISS III stage was significantly lower than that in patients in ISS I stage (0.034+/-0.034 for the ISS III stage versus 0.103+/-0.109 for ISSI stage, p<0.01). Similarly, lower expression levels of cmtm5 gene were also found in two human MM cell lines (0.014+/-0.009 for RPMI8226 cells and 0.004+/-0.006 for CZ1 cells). After the MM patients were effectively treated, their expression levels of cmtm5 gene significantly increased (0.020+/-0.005 for the untreated patients versus 0.227+/-0.038 for the effectively treated patients, p<0.01). A significant negative correlation was observed between the expression level of cmtm5 gene and the number of bone marrow plasma cells (r=-0.307, p<0.05). However, the correlation was not found between the expression level of cmtm5 gene and the clinical characteristics, such as gender, age, hemoglobin level, or M-protein level, etc. It is concluded that the expression level of cmtm5 gene is abnormally lower in the bone marrow cells from the MM patients, and are associated with ISS stages. Furthermore, the expression level of cmtm5 gene is negatively correlated with the number of bone marrow abnormal plasma cells in MM patients, which suggests that the abnormally lower expression of cmtm5 may be involved in the pathogenesis of the MM patients.

MYCN promotes the expansion of Phox2B-positive neuronal progenitors to drive neuroblastoma development.

Amplification of the oncogene MYCN is a tumorigenic event in the development of a subset of neuroblastomas that commonly consist of undifferentiated or poorly differentiated neuroblasts with unfavorable clinical outcome. The cellular origin of these neuroblasts is unknown. Additionally, the cellular functions and target cells of MYCN in neuroblastoma development remain undefined. Here we examine the cell types that drive neuroblastoma development in TH-MYCN transgenic mice, an animal model of the human disease. Neuroblastoma development in these mice begins with hyperplastic lesions in early postnatal sympathetic ganglia. We show that both hyperplasia and primary tumors are composed predominantly of highly proliferative Phox2B(+) neuronal progenitors. MYCN induces the expansion of these progenitors by both promoting their proliferation and preventing their differentiation. We further identify a minor population of undifferentiated nestin(+) cells in both hyperplastic lesions and primary tumors that may serve as precursors of Phox2B(+) neuronal progenitors. These findings establish the identity of neuroblasts that characterize the tumor phenotype and suggest a cellular pathway by which MYCN can promote neuroblastoma development.

Characteristics and prognostic factors of acute myeloid leukemia with t (8; 21) (q22; q22).

The translocation t (8; 21) (q22; q22) frequently associated with additional chromosomal aberrations is one of the most recurrent chromosomal abnormalities in AML. Clinically, this type of AML usually shows some specific characteristics and has a good response to chemotherapy with a high remission rate and a relatively long median survival. On the other hand, some reports also showed poor prognosis in AML patients with t (8; 21), and the associated bad-prognosis factors have not been strongly established to date. To investigate this issue and to further identify the related characteristics of t (8; 21) AML in China, 75 Chinese AML patients with t (8; 21) were retrospectively analyzed. They comprised 68 cases of M(2), five of M(4) and two of M(5) according to FAB classification. The results indicated that Auer rods were observed in 39 patients (52%) and marrow eosinophilia was detected in only 5 patients (6.7%). These patients showed high level of HLA-DR and CD34 expression, while CD19 was detected in only 13 patients (20.9%). Cytogenetically, 62.5% cases had additional chromosomal abnormalities, and the main associated recurrent additional abnormalities were loss of a sex chromosome (LOS), trisomy 4, del (9q) and trisomy 8. After conventional induction therapy, 62 patients attained complete remission (CR) resulting in the CR rate 82.7%. With a follow-up of 1 to 96 months, 19 cases relapsed at a median time of 10.5 months (range 3 to 42 months). The median overall survival was 20 months, and the estimated 5-year overall survival (OS) rate was 32.3%. In multivariate analyses of prognostic factors, karyotype, extramedullary leukemia, age and post-remission therapy were of prognostic value for OS. Patients with additional chromosomal anomalies had shorter survival compared to those with t (8; 21) only (P = 0.019), no matter which kind of additional karyotype it was. Extramedullary leukemia was an adverse prognostic factor (P = 0.012). Patients aged 15 years or less had a longer survival than those aged more than 15 years (P = 0.045). Patients accepted HSCT in post-remission therapy had better outcome compared to those with chemotherapy only. It is concluded that Chinese AML patients with t (8; 21) had some different characteristics as compared with patients from other countries, a relatively poor outcome was observed in our patients, especially in those with extramedullary leukemia or additional chromosomal abnormalities. HSCT should be recommended to t (8; 21) AML in China, especially to those with adverse prognostic factors.

[Two Ph chromosome positive chronic myelogenous leukemia patients with rare bcr/abl fusion gene].

OBJECTIVE: To investigate the unusual bcr/abl fusion gene structures of two Ph chromosome positive chronic myelogenous leukemia (CML) patients in chronic phase (CP). METHODS: By using general M- and micro -bcr/abl specific primers respectively, bcr/abl fusion transcripts were detected by reverse transcription-polymerase chain reaction (RT-PCR). The RT-PCR products sequencing was performed, the DNA sequences were analyzed in Genebank and the bcr and abl sequences at the fusion site were identified. DNA was amplified by PCR using a set of primers designed according to the sequencing result of RT-PCR products. RESULTS: Two patients showed typical manifestations of CML-CP. Their RT-PCR products were different from usual M- or micro -type; one was longer than M-bcr/abl but shorter than micro -bcr/abl, the other one was shorter than M-bcr/abl. The RT-PCR products sequencing showed that both products contained bcr and abl gene sequences. The first patient's bcr gene was broken within exon 18, and fused to abl gene exon 2(a2), and a 40 bp of partial abl intron 1b fragment was inserted between them, resulting in a novel in-frame bcr/abl fusion transcript-e18-int-a2 which has not been reported in the literature so far. In the second patient, deletion of abl exon2(a2) led to exon 13(b2) of bcr gene fusing with abl exon 3(a3). CONCLUSION: Uncommon bcr/abl fusion gene may occur in typical Ph(+) CML patient.

[Bone marrow morphologic features in patients treated with imatinib for Philadelphia chromosome positive chronic myeloid leukemia].

OBJECTIVES: To assess bone marrow morphologic changes in Philadelphia-chromosome positive chronic myeloid leukemia (Ph(+)-CML) patients treated with Imatinib, and to evaluate the correlation of the morphologic changes with hematological or cytogenetic responses. METHODS: One hundred and seventeen patients with Ph(+) CML: 54 in chronic phase but failed to interferon-alpha treatment, 41 in accelerated phase, 22 in blastic phase received oral administration of Imatinib 400 or 600 mg once daily for more than 18 months. RESULTS: All of the patients responded to the treatment, including complete hematological response, bone marrow response and return to chronic phase, bone marrow cellularity and myeloblast count reduced significantly to non-CML picture. Myeloid/erythroid ratio and megkaryocyte count were decreased significantly in most patients in chronic and accelerated phases (P < 0.05). Bone marrow hypoplasia or aplasia was associated with lower cytogenetic response rates in patients in chronic phase (58.8% vs 86.5%, P = 0.035), lower complete hematological response in patients in accelerated phase (26.3% vs 75.0%, P = 0.004), and 6-month overall survival in patients in blastic phase (77.8% vs 16.7%, P = 0.009). Patients in advanced stage obtained non-CML marrow picture in 1 month of treatment had better prognosis. 18-month disease progression rates were lower (25% vs 75%, P = 0.028) and overall survival rates higher (75.0% vs 11.8%, P = 0.004) in patients obtained non-CML picture marrows than in those with CML marrows picture in accelerated phase. Hematological response rate and overall survival of more than 6 months were higher in patients with non-CML marrows picture than those with CML marrows picture (100.0% vs 40.0%, P = 0.017 and 83.3% vs 26.7%, P = 0.046 respectively) in blastic phase. CONCLUSIONS: Normal marrow appearance can be sustained under continuous treatment of Imatinib in CML patients who achieved hematological responses.

[A serial study of in cytogenetic change and morphology on the tetra-arsenic tetra-sulfide treatment in untreated or recurrent acute promyelocytic leukemia].

OBJECTIVE: To study the morphologic and cytogenetic change in acute promyelocytic leukemia (APL) patients during the tetra-arsenic tetra-sulfide (TATS) treatment and the mechanism of TATS. METHODS: The bone marrow cells of 13 newly diagnosed and 7 recurrent APL patients were studied through FISH and morphology during the TATS treatment by special and repeated marrow culture. RESULTS: Cytomorphological study of 8 cases (6 untreated and 2 recurrent) showed that TATS could differentiate APL cells forward to mature granulocytes. There was obvious correlation between the reduced t (15; 17) positive cells and the reduced APL cells (r range 0.7298 - 0.9989). Except one patient with t (11; 17), 19 (13 untreated and 7 recurrent) with translocation t (15; 17) achieved clinical CR including 16 who achieved cytogenetic CR. CONCLUSION: TATS has a differentiation-inducing effect on untreated and recurrent APL, with haematological CR and cytogenetic CR achieved. Measurement of t (15; 17) positive cells by FISH technique can reflect the change of APL cells objectively.