), the authors note that in Fig. 1D Right, the x-axis labels were transposed. The corrected figure and its legend appear below. MECs were isolated from BALB/c mice, cultured for 3 days, irradiated, and analyzed for %SP by Hoechst 33342 staining and flow cytometry. Radiation selectively increased the progenitor fraction (%SP) (P ϭ 0.015 for 2 Gy, 0.008 for 4 Gy, and 0.05 for 6 Gy by the two-tailed t test). (B) MCF-7 cells were analyzed for %SP by Hoechst 33342 staining and flow cytometry. Radiation selectively increased the progenitor fraction (%SP) (P ϭ 0.05 for 0 Gy vs. 4 Gy by the two-tailed t test). (C) Cells were analyzed for Sca1 in the SP 24 h after irradiation. Radiation selectively increased the Sca1 ϩ (progenitor) fraction within the SP by killing the more sensitive Sca1 Ϫ (nonprogenitor) cells (P Ͻ 0.05 for Sca1 ϩ to Sca1 Ϫ at 0 Gy vs. 2-8 Gy). The differences in effects of doses of 2 Gy vs. higher doses were not significant. (D) Anesthetized BALB/c mice were immobilized supine, and mammary glands (entire ventral surface) were irradiated. MECs were isolated 48 h after irradiation and analyzed immediately for Sca1 by flow cytometry. Radiation selectively increased the Sca1 ϩ (progenitor) fraction and decreased the Sca1 Ϫ (nonprogenitor)

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ObjectiveNon-alcoholic fatty liver disease (NAFLD) is an important co-morbidity associated with obesity and a precursor to steatohepatitis. However, the contributions of gestational and early life influences on development of NAFLD and NASH remain poorly appreciated.MethodsTwo independent studies were performed to examine whether maternal over-nutrition via exposure to high fat diet (HFD) leads to exacerbated hepatic responses to post-natal HFD and methionine choline deficient (MCD) diets in the offspring. Offspring of both control diet- and HFD-fed dams were weaned onto control and HFD, creating four groups.ResultsWhen compared to their control diet-fed littermates, offspring of HF-dams weaned onto HFD gained greater body weight; had increased relative liver weight and showed hepatic steatosis and inflammation. Similarly, this group revealed significantly greater immune response and pro-fibrogenic gene expression via RNA-seq. In parallel, 7–8 week old offspring were challenged with either control or MCD diets for 3 weeks. Responses to MCD diets were also exacerbated due to maternal HFD as seen by gene expression of classical pro-fibrogenic genes. Quantitative genome-scale DNA methylation analysis of over 1 million CpGs showed persistent epigenetic changes in key genes in tissue development and metabolism (Fgf21, Ppargc1β) with maternal HFD and in cell adhesion and communication (VWF, Ephb2) in the combination of maternal HFD and offspring MCD diets. Maternal HFD also influenced gut microbiome profiles in offspring leading to a decrease in α-diversity. Linear regression analysis revealed association between serum ALT levels and Coprococcus, Coriobacteriacae, Helicobacterioceae and Allobaculum.ConclusionOur findings indicate that maternal HFD detrimentally alters epigenetic and gut microbiome pathways to favor development of fatty liver disease and its progressive sequelae.

Wnt signaling plays an important role in developmental and stem cell biology. To test the hypothesis that temporary inhibition of Wnt signaling will enhance granulation tissue and promote angiogenesis in tissue repair, we employed a recently characterized small molecule Wnt inhibitor. Pyrvinium is an FDA-approved drug that we identified as a Wnt inhibitor in a chemical screen for small molecules that stabilize β-catenin and inhibit Axin degradation. Our subsequent characterization of pyrvinium has revealed that its critical cellular target in the Wnt pathway is Casein Kinase 1α. Daily administration of pyrvinium directly into polyvinyl alcohol (PVA) sponges implanted subcutaneously in mice generated better organized and vascularized granulation tissue; this compound also increased the proliferative index of the tissue within the sponges. To evaluate its effect in myocardial repair, we induced a myocardial infarction (MI) by coronary artery ligation and administered a single intramyocardial dose of pyrvinium. Mice were evaluated by echocardiography at 7 and 30 days post-MI and treatment; post mortem hearts were evaluated by histology at 30 days. Pyrvinium reduced adverse cardiac remodeling demonstrated by decreased left ventricular internal diameter in diastole (LVIDD) as compared to a control compound. Increased Ki-67+ cells were observed in peri-infarct and distal myocardium of pyrvinium-treated animals. These results need to be further followed-up to determine if therapeutic inhibition of canonical Wnt may avert adverse remodeling after ischemic injury and its impact on myocardial repair and regeneration.

radiation. Expression of active ␤-catenin enhanced selfrenewal preferentially in the Sca1 + cells, whereas suppressing ␤-catenin with a dominant negative, ␤-engrailed, decreased self-renewal of the Sca1 + cells. Understanding the radioresistance of progenitor cells may be an important factor in improving the treatment of cancer. The COMMA-D␤-geo cell line may provide a useful model to study the signaling pathways that control mammary progenitor cell regulation.

Transplantation of mesenchymal stem cells (MSCs) is a promising therapy for ischemic injury; however, inadequate survival of implanted cells in host tissue is a substantial impediment in the progress of cellular therapy. Secreted Frizzled-related protein 2 (sFRP2) has recently been highlighted as a key mediator of MSC-driven myocardial and wound repair. Notably, sFRP2 mediates significant enhancement of MSC engraftment in vivo. We hypothesized that sFRP2 improves MSC engraftment by modulating self-renewal through increasing stem cell survival and by inhibiting differentiation. In previous studies we demonstrated that sFRP2-expressing MSCs exhibited an increased proliferation rate. In the current study, we show that sFRP2 also decreased MSC apoptosis and inhibited both osteogenic and chondrogenic lineage commitment. sFRP2 activity occurred through the inhibition of both Wnt and bone morphogenic protein (BMP) signaling pathways. sFRP2-mediated inhibition of BMP signaling, as assessed by levels of pSMAD 1/5/8, was independent of its effects on the Wnt pathway. We further hypothesized that sFRP2 inhibition of MSC lineage commitment may reduce heterotopic osteogenic differentiation within the injured myocardium, a reported adverse side effect. Indeed, we found that sFRP2-MSC-treated hearts and wound tissue had less ectopic calcification. This work provides important new insight into the mechanisms by which sFRP2 increases MSC self-renewal leading to superior tissue engraftment and enhanced wound healing.Bone marrow-derived mesenchymal stem cells (MSCs) 2 are an attractive candidate for cell-mediated wound repair. Because of their plasticity, MSCs have been utilized in several preclinical and clinical trials of tissue regeneration (1).3 MSCs have been able to repair infarcted myocardium, bone, and soft tissue, albeit with varying degrees of success (3). These promising results are inconsistent, partly due to the low levels of engraftment of MSCs within the injured tissues (4). Hence, strategies to increase survival and engraftment within the wound may enhance MSC therapy.Self-renewal is an intrinsic property of stem cells that allows them to give rise to non-differentiated daughter cells by proliferating, preventing apoptosis, and avoid lineage commitment (5, 6). This process is important for the maintenance of a stem cell pool that, in the case of MSCs, can exert a more robust effect within the context of a wound. Although several cytokines, growth factors, adhesion molecules, and extracellular matrix components have been identified as cues that signal MSCs to differentiate, the molecular signals that modulate MSC self-renewal remain unknown (5). Data from the hematopoietic stem cell (HSC) field have documented the involvement of Wnt, Notch, and BMP signaling cascades in self-renewal; these pathways are implicated in the expansion of undifferentiated HSCs that upon transplantation into lethally irradiated mice successfully reconstitute the cleared bone marrow (7-9). Although no data are available to demonstrate the...

The contributions of maternal diet and obesity in shaping offspring microbiome remain unclear. Here we employed a mouse model of maternal diet-induced obesity via high-fat diet feeding (HFD, 45% fat calories) for 12 wk prior to conception on offspring gut microbial ecology. Male and female offspring were provided access to control or HFD from weaning until 17 wk of age. Maternal HFD-associated programming was sexually dimorphic, with male offspring from HFD dams showing hyper-responsive weight gain to postnatal HFD. Likewise, microbiome analysis of offspring cecal contents showed differences in α-diversity, β-diversity and higher Firmicutes in male compared to female mice. Weight gain in offspring was significantly associated with abundance of Lachnospiraceae and Clostridiaceae families and Adlercreutzia, Coprococcus and Lactococcus genera. Sex differences in metagenomic pathways relating to lipid metabolism, bile acid biosynthesis and immune response were also observed. HFD-fed male offspring from HFD dams also showed worse hepatic pathology, increased pro-inflammatory cytokines, altered expression of bile acid regulators (Cyp7a1, Cyp8b1 and Cyp39a1) and serum bile acid concentrations. These findings suggest that maternal HFD alters gut microbiota composition and weight gain of offspring in a sexually dimorphic manner, coincident with fatty liver and a pro-inflammatory state in male offspring.

Cell identity is determined by its gene expression programs. The ability of a cell to change its identity and produce cell types outside its lineage is achieved by the activity of transcription controllers capable of reprogramming differentiation gene networks. The synovial sarcoma (SS)-associated protein, SYT–SSX2, reprograms myogenic progenitors and human bone marrow-derived mesenchymal stem cells (BMMSCs) by dictating their commitment to a pro-neural lineage. It fulfills this function by directly targeting an extensive array of neural-specific genes as well as genes of developmental pathway mediators. Concomitantly, the ability of both myoblasts and BMMSCs to differentiate into their normal myogenic and adipogenic lineages was compromised. SS is believed to arise in mesenchymal stem cells where formation of the t(X/18) translocation product, SYT–SSX, constitutes the primary event in the cancer. SYT–SSX is therefore believed to initiate tumorigenesis in its target stem cell. The data presented here allow a glimpse at the initial events that likely occur when SYT–SSX2 is first expressed, and its dominant function in subverting the nuclear program of the stem cell, leading to its aberrant differentiation, as a first step toward transformation. In addition, we identified the fibroblast growth factor receptor gene, Fgfr2, as one occupied and upregulated by SYT–SSX2. Knockdown of FGFR2 in both BMMSCs and SS cells abrogated their growth and attenuated their neural phenotype. These results support the notion that the SYT–SSX2 nuclear function and differentiation effects are conserved throughout sarcoma development and are required for its maintenance beyond the initial phase. They also provide the stem cell regulator, FGFR2, as a promising candidate target for future SS therapy.