Bone Marrow and Adipose‐Derived Mesenchymal Stem Cells Alleviate Methotrexate‐Induced Pulmonary Fibrosis in Rat: Comparison with Dexamethasone

The present study examined the therapeutic effects of bone marrow mesenchymal stem cells (BM‐MSCs) and adipose‐derived mesenchymal stem cells (AD‐MSCs) in methotrexate (MTX)‐induced pulmonary fibrosis in rats as compared with dexamethasone (Dex). MTX (14 mg/kg, as a single dose/week for 2 weeks, p.o.) induced lung fibrosis as marked by elevation of relative lung weight, malondialdehyde, nitrite/nitrate, interleukin‐4, transforming growth factor‐β1, deposited collagen, as well as increased expression of Bax along with the reduction of reduced glutathione content and superoxide dismutase activity. These deleterious effects were antagonized after treatment either with BM‐MSCs or AD‐MSCs (2 × 10⁶ cells/rat) 2 weeks after MTX to even a better extent than Dex (0.5 mg/kg/ for 7 days, p.o.). In conclusion, BM‐MSC and AD‐MSCs possessed antioxidant, antiapoptotic, as well as antifibrotic effects, which will probably introduce them as remarkable candidates for the treatment of pulmonary fibrosis.     

Vertebral Bone Marrow Fat Is Positively Associated With Visceral Fat and Inversely Associated With IGF‐1 in Obese Women

Recent studies have demonstrated an important physiologic link between bone and fat. Bone and fat cells arise from the same mesenchymal precursor cell within bone marrow, capable of differentiation into adipocytes or osteoblasts. Increased BMI appears to protect against osteoporosis. However, recent studies have suggested detrimental effects of visceral fat on bone health. Increased visceral fat may also be associated with decreased growth hormone (GH) and insulin‐like growth factor 1 (IGF‐1) levels which are important for maintenance of bone homeostasis. The purpose of our study was to assess the relationship between vertebral bone marrow fat and trabecular bone mineral density (BMD), abdominal fat depots, GH and IGF‐1 in premenopausal women with obesity. We studied 47 premenopausal women of various BMI (range: 18–41 kg/m², mean 30 ± 7 kg/m²) who underwent vertebral bone marrow fat measurement with proton magnetic resonance spectroscopy (1H‐MRS), body composition, and trabecular BMD measurement with computed tomography (CT), and GH and IGF‐1 levels. Women with high visceral fat had higher bone marrow fat than women with low visceral fat. There was a positive correlation between bone marrow fat and visceral fat, independent of BMD. There was an inverse association between vertebral bone marrow fat and trabecular BMD. Vertebral bone marrow fat was also inversely associated with IGF‐1, independent of visceral fat. Our study showed that vertebral bone marrow fat is positively associated with visceral fat and inversely associated with IGF‐1 and BMD. This suggests that the detrimental effect of visceral fat on bone health may be mediated in part by IGF‐1 as an important regulator of the fat and bone lineage.     

Cardiomyocyte Protection by GATA-4 Gene Engineered Mesenchymal Stem Cells Is Partially Mediated by Translocation of miR-221 in Microvesicles

Introduction

microRNAs (miRs), a novel class of small non-coding RNAs, are involved in cell proliferation, differentiation, development, and death. In this study, we found that miR-221 translocation by microvesicles (MVs) plays an important role in cardioprotection mediated by GATA-4 overexpressed mesenchymal stem cells (MSC).

Methods and Results

Adult rat bone marrow MSC and neonatal rat ventricle cardiomyocytes (CM) were harvested as primary cultures. MSC were transduced with GATA-4 (MSC^GATA-4) using the murine stem cell virus (pMSCV) retroviral expression system. Empty vector transfection was used as a control (MSC^Null). The expression of miRs was assessed by real-time PCR and localized using in situ hybridization (ISH). MVs collected from MSC cultures were characterized by expression of CD9, CD63, and HSP70, and photographed with electron microscopy. Cardioprotection during hypoxia afforded by conditioned medium (CdM) from MSC cultures was evaluated by lactate dehydrogenase (LDH) release, MTS uptake by CM, and caspase 3/7 activity. Expression of miR-221/222 was significantly higher in MSC than in CM and miR-221 was upregulated in MSC^GATA-4. MSC overexpression of miR-221 significantly enhanced cardioprotection by reducing the expression of p53 upregulated modulator of apoptosis (PUMA). Moreover, expression of PUMA was significantly decreased in CM co-cultured with MSC. MVs derived from MSC expressed high levels of miR-221, and were internalized quickly by CM as documented in images obtained from a Time-Lapse Imaging System.

Conclusions

Our results demonstrate that cardioprotection by MSC^GATA-4 may be regulated in part by a transfer of anti-apoptotic miRs contained within MVs.     

Asymmetric Distribution of UCH‐L1 in Spermatogonia Is Associated With Maintenance and Differentiation of Spermatogonial Stem Cells

Asymmetric division of germline stem cells in vertebrates was proposed a century ago; however, direct evidence for asymmetric division of mammalian spermatogonial stem cells (SSCs) has been scarce. Here, we report that ubiquitin carboxy‐terminal hydrolase 1 (UCH‐L1) is expressed in type A (A_s, A_pr, and A_al) spermatogonia located at the basement membrane (BM) of seminiferous tubules at high and low levels, but not in differentiated germ cells distant from the BM. Asymmetric segregation of UCH‐L1 was associated with self‐renewal versus differentiation divisions of SSCs as defined by co‐localization of UCH‐L1^high and PLZF, a known determinant of undifferentiated SSCs, versus co‐localization of UCH‐L1^low/? with proteins expressed during SSC differentiation (DAZL, DDX4, c‐KIT). In vitro, gonocytes/spermatogonia frequently underwent asymmetric divisions characterized by unequal segregation of UCH‐L1 and PLZF. Importantly, we could also demonstrate asymmetric segregation of UCH‐L1 and PLZF in situ in seminiferous tubules. Expression level of UCH‐L1 in the immature testis where spermatogenesis was not complete was not affected by the location of germ cells relative to the BM, whereas UCH‐L1‐positive spermatogonia were exclusively located at the BM in the adult testis. Asymmetric division of SSCs appeared to be affected by interaction with supporting somatic cells and extracelluar matrix. These findings for the first time provide direct evidence for existence of asymmetric division during SSCs self‐renewal and differentiation in mammalian spermatogenesis. J. Cell. Physiol. 220: 460–468, 2009. © 2009 Wiley‐Liss, Inc.     

Hesperetin Inhibit Adipocyte Differentiation and Enhance Bax‐ and p21‐Mediated Adipolysis in Human Mesenchymal Stem Cell Adipogenesis

We aimed to explore the antiadipogenic and adipolysis effect of hesperetin in human mesenchymal stem cells (hMSCs)–induced adipogenesis. IC₅₀ value of hesperetin was higher for hMSCs such as 149.2 ± 13.2 μmol for 24 h and 89.4 ± 11.4 μmol in 48 h, whereas in preadipocytes was 87.6 ± 9.5 μmol and 72.4 ± 5.6 μmol in 24 h and 48 h, respectively. Hesperetin treatment (5, 10, and 20 μmol) to adipogenesis‐induced hMSCs (Group 1) and preadipocytes (Group 2) resulted in a significantly (p < 0.05) increased lipolysis. The treatment with hesperetin decreased the expression of resistin, adiponectin, aP₂, LPL, PPAR‐γ, and TNF‐α in Groups 1 and 2, whereas a significant increase was observed in Bcl, Bax, and p21 expression in Group 2 compared to untreated preadipocytes. hMSCs cultured in adipogenic medium along with hesperetin significantly inhibited adipocyte differentiation and increased the proapoptotic gene expression levels in preadipocyte. Our result indicates the antiadipogenic and adipolysis effects of hesperetin.