Skeletal muscle satellite (stem) cells are quiescent in adult mice and can undergo multiple rounds of proliferation and self-renewal following muscle injury. Several labs have profiled transcripts of myogenic cells during the developmental and adult myogenesis with the aim of identifying quiescent markers. Here, we focused on the quiescent cell state and generated new transcriptome profiles that include subfractionations of adult satellite cell populations, and an artificially induced prenatal quiescent state, to identify core signatures for quiescent and proliferating.

Satellite cells are quiescent resident muscle stem cells that present an important potential to regenerate damaged tissue. However, this potential is diminished once they are removed from their niche environment in vivo, prohibiting the long-term study and genetic investigation of these cells. This study therefore aimed to provide a novel biomaterial platform for the in-vitro culture of human satellite cells that maintains their stem-like quiescent state, an important step for cell therapeutic studies.

Bone morphogenetic proteins (BMPs) induce osteogenesis in various environments. However, when BMPs are used alone in the bone marrow environment, the maintenance of new bone formation is difficult owing to vigorous bone resorption. This is because BMPs stimulate the differentiation of not only osteoblast precursor cells but also osteoclast precursor cells. The present study aimed to induce and maintain new bone formation using the topical co-administration of recombinant human BMP-2 (rh-BMP-2) and zoledronate (ZOL) on beta-tricalcium phosphate (β-TCP) composite.

Developmental dysplasia of the hip (DDH) is characterized by anatomical abnormalities of the hip joint, ranging from mild acetabular dysplasia to hip subluxation and eventually dislocation. The mechanism underlying the cartilage degeneration of the hip joints exposed to reduced dynamic loads due to hip dislocation remains unknown. We established a rodent hip dislocation (disarticulation; DA) model of DDH (DA-DDH rats and mice) by swaddling. Expression levels of periostin (Postn) and catabolic factors, such as interleukin-6 (IL-6) and matrix metalloproteinase 3 (Mmp3), increased and those of chondrogenic markers decreased in the acetabular cartilage of the DA-DDH models. Postn induced IL-6 and Mmp3 expression in chondrocytes through integrin αVβ3, focal adhesion kinase, Src, and nuclear factor-κB (NF-κB) signaling. The microgravity environment created by a random positioning machine induced Postn expression in chondrocytes through signal transducer and activator of transcription 3 (STAT3) signaling. IL-6 stimulated Postn expression via STAT3 signaling. Furthermore, cartilage degeneration was suppressed in the acetabulum of Postn-/- DA-DDH mice compared with that in the acetabulum of wild type DA-DDH mice. In summary, reduced dynamic loads due to hip dislocation induced acetabular cartilage degeneration via IL-6 and MMP3 through STAT3/periostin/NF-κB signaling in the rodent DA-DDH models.

Anti-CD2 treatment provides targeted immunomodulatory properties that have demonstrated clinical usefulness to condition the immune system and to treat transplant rejection. The treatment is species-specific due to structural CD2 antigen differences between nonhuman primates and humans. Herein, we report the safety profile and efficacy of two modifications of the same anti-CD2 monoclonal antibody in cynomolgus macaques. Twelve subjects received one i.v. anti-CD2 (of rat or rhesus type) dose each, range 1-4 mg/kg, and were followed for 1-7 days. Treatment effects were evaluated with flow cytometry on peripheral blood and histopathological evaluation of secondary lymphoid organs. In vitro inhibitory activity on primary MHC disparate mixed lymphocyte reactions (MLRs) was determined. Upon anti-CD2 treatment, CD4+ , CD8+ memory subsets were substantially depleted. Naïve T cells and Tregs were relatively spared and exhibited lower CD2 expression than memory T cells. Early immune reconstitution was noted for naïve cells, while memory counts had not recovered after one week. Both antibodies displayed a concentration-dependent MLR inhibition. Lymph node examination revealed no significant lymphocyte depletion. None of the animals experienced any significant study drug-related adverse events. This study outlines the safety and pharmacodynamic profile of primate-specific anti-CD2 treatment, relevant for translation of anti-CD2-based animal models into clinical trials.

Resistance training (RT) has been known to be effective in maintaining and improving bone strength, which is based on bone mineral density (BMD) and bone quality. However, it is not clear whether RT is effective in improving bone strength in patients with type-2 diabetes mellitus (T2DM), who have a high risk of fracture. Therefore, we tested the effects of a 6-week RT regimen using percutaneous electrical stimulation in T2DM model rats, male Otsuka Long-Evans Tokushima Fatty (OLETF), and its control, Long-Evans Tokushima Otsuka (LETO). After 6 weeks of RT, tibial BMD in RT legs was significantly higher than that in control (CON) legs in both groups. In diaphyseal cortical bone, bone area/tissue area, and cortical thickness was significantly increased in RT legs compared with CON legs in both groups. Cortical porosity was highly observed in OLETF compared with LETO, but RT improved cortical porosity in both groups. Interestingly, trabecular number, trabecular thickness and trabecular space as well as BMD and bone volume/tissue volume in proximal tibial metaphyseal trabecular bone were significantly improved in RT legs compared with CON legs in both groups. In contrast, connectivity density and structural model index were not affected by RT. These results indicate that the 6-week RT regimen effectively increased BMD and improved bone quality in T2DM model rats as well as control rats. Therefore, RT may have the potential to improve bone strength and reduce fracture risk, even in patients with T2DM.

TGF-ß is a multifunctional cytokine that is involved in cell proliferation, differentiation and function. We previously reported an essential role of the TGF-ß -Smad2/3 pathways in RANKL-induced osteoclastogenesis. Using chromatin immunoprecipitation followed by sequencing, we comprehensively identified Smad2/3 target genes in bone marrow macrophages. These genes were enriched in the gene population upregulated by TGF-ß and downregulated by RANKL. Recent studies have revealed that histone modifications, such as trimethylation of histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3), critically regulate key developmental steps. We identified Nedd9 as a Smad2/3 target gene whose histone modification pattern was converted from H3K4me3(+)/H3K4me27(+) to H3K4me3(+)/H3K4me27(-) by TGF-ß. Nedd9 expression was increased by TGF-ß and suppressed by RANKL. Overexpression of Nedd9 partially rescued an inhibitory effect of a TGF-ß inhibitor, while gene silencing of Nedd9 suppressed RANKL-induced osteoclastogenesis. RANKL-induced osteoclastogenesis were reduced and stimulatory effects of TGF-ß on RANKL-induced osteoclastogenesis were partially abrogated in cells from Nedd9-deficient mice although knockout mice did not show abnormal skeletal phenotypes. These results suggest that Nedd9 is a Smad2/3 target gene implicated in RANKL-induced osteoclastogenesis.

Myogenic stem cells are a promising avenue for the treatment of muscular disorders. Freshly isolated muscle stem cells have a remarkable engraftment ability in vivo, but their cell number is limited. Current conventional culture conditions do not allow muscle stem cells to expand in vitro with their bona fide engraftment efficiency, requiring the improvement of culture procedures for achieving successful cell-therapy for muscle disorders. Here we expanded mouse muscle stem cells and human myoblasts with Notch ligands, DLL1, DLL4, and JAG1 to activate Notch signaling in vitro and to investigate whether these cells could retain their engraftment efficiency. Notch signaling promotes the expansion of Pax7+MyoD- mouse muscle stem-like cells and inhibits differentiation even after passage in vitro. Treatment with Notch ligands induced the Notch target genes and generated PAX7+MYOD- stem-like cells from human myoblasts previously cultured on conventional culture plates. However, cells treated with Notch ligands exhibit a stem cell-like state in culture, yet their regenerative ability was less than that of freshly isolated cells in vivo and was comparable to that of the control. These unexpected findings suggest that artificial maintenance of Notch signaling alone is insufficient for improving regenerative capacity of mouse and human donor-muscle cells and suggest that combinatorial events are critical to achieve muscle stem cell and myoblast engraftment potential.

Pancreatic lineage-specific transcription factors (TFs) display instructive roles in converting adult cells to endocrine pancreatic cells through a process known as transdifferentiation. However, little is known about potential factors capable of accelerating transdifferentiation following transduction to achieve the functional maturation of transdifferentiated cells. In this study, we demonstrated, using adult liver-derived progenitor cells, that soluble factors utilized in pancreatic differentiation protocols of pluripotent stem cells promote functional maturation of TFs-mediated transdifferentiated cells. Treatment with an N2 supplement in combination with three soluble factors (glucagon-like peptide-1 [GLP-1] receptor agonist, notch inhibitor, and transforming growth factor-β [TGF-β] inhibitor) enhanced liver-to-pancreas transdifferentiation based on the following findings: i) the incidence of c-peptide-positive cells increased by approximately 1.2-fold after the aforementioned treatment; ii) the c-peptide expression level in the treated cells increased by approximately 12-fold as compared with the level in the untreated cells; iii) the treated cells secreted insulin in a glucose-dependent manner, whereas the untreated cells did not; and iv) transplantation of treated-transdifferentiated cells into streptozotocin-induced immunodeficient diabetic mice led to the amelioration of hyperglycemia. These results suggest that treatment with specific soluble factors promotes the functional maturation of transdifferentiated cells. Our findings could facilitate the development of new modalities for cell-replacement therapy for patients with diabetes.

Induced pluripotent stem (iPS) cells are generated from adult somatic cells by transduction of defined factors. Given their unlimited proliferation and differentiation potential, iPS cells represent promising sources for cell therapy and tools for research and drug discovery. However, systems for the directional differentiation of iPS cells toward paraxial mesodermal lineages have not been reported. In the present study, we established a protocol for the differentiation of mouse iPS cells into paraxial mesodermal lineages in serum-free culture. The protocol was dependent on Activin signaling in addition to BMP and Wnt signaling which were previously shown to be effective for mouse ES cell differentiation. Independently of the cell origin, the number of transgenes, or the type of vectors used to generate iPS cells, the use of serum-free monolayer culture stimulated with a combination of BMP4, Activin A, and LiCl enabled preferential promotion of mouse iPS cells to a PDGFR-α(+)/Flk-1(-) population, which represents a paraxial mesodermal lineage. The mouse iPS cell-derived paraxial mesodermal cells exhibited differentiation potential into osteogenic, chondrogenic, and myogenic cells both in vitro and in vivo and contributed to muscle regeneration. Moreover, purification of the PDGFR-α(+)/KDR(-) population after differentiation allowed enrichment of human iPS cell populations with paraxial mesodermal characteristics. The resultant PDGFR-α(+)/KDR(-) population derived from human iPS cells specifically exhibited osteogenic, chondrogenic, and myogenic differentiation potential in vitro, implying generation of paraxial mesodermal progenitors similar to mouse iPS cell-derived progenitors. These findings highlight the potential of protocols based on the serum-free, stepwise induction and purification of paraxial mesodermal cell lineages for use in stem cell therapies to treat diseased bone, cartilage, and muscle.

The MET inhibitor tepotinib demonstrated durable clinical activity in patients with advanced MET exon 14 (METex14) skipping NSCLC. We report detailed analyses of adverse events of clinical interest (AECIs) in VISION, including edema, a class effect of MET inhibitors.

The severity of liver fibrosis has been reported to be correlated with the risk of intractable ascites after hepatectomy for hepatocellular carcinoma. Since 2009, we have measured routinely the serum concentrations of type IV collagen 7s domain (7s collagen), a biochemical marker of liver fibrosis and applied limited resection to patients with elevation of the serum 7s collagen concentrations above the upper limit of normal (6.0 ng/mL). The aim of this study was to assess the potential benefits of our treatment strategy on the postoperative outcomes of patients with hepatocellular carcinoma.

In vivo reprogramming is a promising approach for tissue regeneration in response to injury. Several examples of in vivo reprogramming have been reported in a variety of lineages, but some including skeletal muscle have so far proven refractory. Here, we show that acute and chronic injury enables transcription-factor-mediated reprogramming in skeletal muscle. Lineage tracing indicates that this response frequently originates from Pax7+ muscle stem cells. Injury is associated with accumulation of senescent cells, and advanced aging or local irradiation further enhanced in vivo reprogramming, while selective elimination of senescent cells reduced reprogramming efficiency. The effect of senescence appears to be, at least in part, due to the release of interleukin 6 (IL-6), suggesting a potential link with the senescence-associated secretory phenotype. Collectively, our findings highlight a beneficial paracrine effect of injury-induced senescence on cellular plasticity, which will be important for devising strategies for reprogramming-based tissue repair.

Epigenetic transcriptional regulation is essential for the differentiation of various types of cells, including skeletal muscle cells. DNA methyltransferase 1 (Dnmt1) is responsible for maintenance of DNA methylation patterns via cell division. Here, we investigated the relationship between Dnmt1 and skeletal muscle regeneration. We found that Dnmt1 is upregulated in muscles during regeneration. To assess the role of Dnmt1 in satellite cells during regeneration, we performed conditional knockout (cKO) of Dnmt1 specifically in skeletal muscle satellite cells using Pax7CreERT2 mice and Dnmt1 flox mice. Muscle weight and the cross-sectional area after injury were significantly lower in Dnmt1 cKO mice than in control mice. RNA sequencing analysis revealed upregulation of genes involved in cell adhesion and apoptosis in satellite cells from cKO mice. Moreover, satellite cells cultured from cKO mice exhibited a reduced number of cells. These results suggest that Dnmt1 is an essential factor for muscle regeneration and is involved in positive regulation of satellite cell number.

Macrophages are progenitors of osteoclasts as well as regulators of bone metabolism. Macrophages mediate not only bone formation by osteoblasts under physiological conditions, but also bone regeneration after fracture. The mechanisms of macrophages regulation of bone formation and regeneration remain unclear, however. Here, we demonstrate that the liposome-encapsulated Clodronate (Clod-lip) injected mouse model with cortical bone defect induced by drill-hole injury and targeted depletion of phagocytic macrophages exhibits impaired angiogenesis of type H vessels that couple angiogenesis and osteogenesis. Moreover, we identify Tgfbi (encoding TGFBI), Plau (encoding uPA) and Tgfb1 (encoding TGF-β1), through RNA-seq analysis, as genes of macrophage-secreted factors mediating angiogenesis and wound healing. The relevant mRNA was highly expressed in bone marrow-derived macrophages among bone cells, as determined through qRT-PCR. Finally, we disclose that treatment with uPA inhibitor or TGF-β receptor I, receptor II inhibitor impairs bone regeneration after injury, confirming the importance of uPA and TGF-β1 during bone regeneration. Our findings reveal a novel mechanism of bone regeneration mediated by macrophages.

Lenalidomide, an immunomodulatory drug (IMiD), is commonly used as a first-line therapy in many haematological cancers, such as multiple myeloma (MM) and 5q myelodysplastic syndromes (5q MDS), and it functions as a molecular glue for the protein degradation of neosubstrates by CRL4CRBN. Proteolysis-targeting chimeras (PROTACs) using IMiDs with a target protein binder also induce the degradation of target proteins. The targeted protein degradation (TPD) of neosubstrates is crucial for IMiD therapy. However, current IMiDs and IMiD-based PROTACs also break down neosubstrates involved in embryonic development and disease progression. Here, we show that 6-position modifications of lenalidomide are essential for controlling neosubstrate selectivity; 6-fluoro lenalidomide induced the selective degradation of IKZF1, IKZF3, and CK1α, which are involved in anti-haematological cancer activity, and showed stronger anti-proliferative effects on MM and 5q MDS cell lines than lenalidomide. PROTACs using these lenalidomide derivatives for BET proteins induce the selective degradation of BET proteins with the same neosubstrate selectivity. PROTACs also exert anti-proliferative effects in all examined cell lines. Thus, 6-position-modified lenalidomide is a key molecule for selective TPD using thalidomide derivatives and PROTACs.

The feasibility and efficacy of surgical resection following systemic therapy for intermediate-stage hepatocellular carcinoma (HCC) beyond the Up-to-7 criteria is unclear. The combination of lenvatinib (LEN) and transcatheter arterial chemoembolisation (TACE), termed LEN-TACE sequential therapy, has shown a high response rate and survival benefit in patients with intermediate-stage HCC. This trial aims to evaluate the efficacy and safety of LEN-TACE sequential therapy and the feasibility of surgical resection for intermediate-stage HCC beyond the Up-to-7 criteria.

Osteophyte formation is attracting attention as an early-stage pathology of knee osteoarthritis (OA). Although osteophyte formation is understood as a defense response to joint instability, its role and impact on OA remain largely unknown. Many studies have been conducted using the surgical destabilization of the medial meniscus (DMM) mouse model, but there are few standard evaluation methods, especially in the histological evaluation of early-stage osteophytes. The purpose of this study was to establish a reproducible and uniform method for histological evaluation of characteristics of early osteophyte formation in the DMM mouse model.

The Long-Evans Cinnamon (LEC) rat, an animal model of human Wilson's disease, spontaneously develops fulminant hepatitis associated with severe jaundice at about 4 months of age. In this study, we examined the changes in gene expression during progression of acute hepatic injury. When levels of gene expression in the liver of LEC rats at 13 weeks of age were compared to those in rats at 4 weeks of age using oligonucleotide arrays, 1,620 genes out of 7,700 genes analyzed showed more than 2-fold differences. Expression levels of 11 of 29 genes related to stress-activating protein kinase (SAPK) changed by more than 2-fold in the liver of LEC rats, but none of the SAPK-related genes showed changes in expression levels in the liver of control rats. Activity of p38 mapk in the liver of LEC rats at 13 weeks of age was about 8.1-fold higher than that in rats at 4 weeks of age. When LEC rats were administered SB203580, a p38 mapk-specific inhibitor, by s.c. injection twice a week from 10 to 13 weeks of age, activities of p38 mapk in the liver, activities of AST and ALT and concentrations of bilirubin in sera of rats administered SB203580 significantly decreased compared to those in rats not administered. These results showed that the increase in activities of p38 mapk was related to the occurrence of acute hepatic injury in LEC rats.

The bulbocavernosus (BC) is a sexually dimorphic muscle observed only in males. Androgen receptor knockout mouse studies show the loss of BC formation. This suggests that androgen signaling plays a vital role in its development. Androgen has been known to induce muscle hypertrophy through satellite cell activation and myonuclei accretion during muscle regeneration and growth. Whether the same mechanism is present during embryonic development is not yet elucidated. To identify the mechanism of sexual dimorphism during BC development, the timing of morphological differences was first established. It was revealed that the BC was morphologically different between male and female mice at embryonic day (E) 16.5. Differences in the myogenic process were detected at E15.5. The male BC possesses a higher number of proliferating undifferentiated myoblasts. To identify the role of androgen signaling in this process, muscle-specific androgen receptor (AR) mutation was introduced, which resulted in no observable phenotypes. Hence, the expression of AR in the BC was examined and found that the AR did not colocalize with any muscle markers such as Myogenic differentiation 1, Myogenin, and paired box transcription factor 7. It was revealed that the mesenchyme surrounding the BC expressed AR and the BC started to express AR at E15.5. AR mutation on the nonmyocytic cells using spalt-like transcription factor 1 (Sall1) Cre driver mouse was performed, which resulted in defective BC formation. It was revealed that the number of proliferating undifferentiated myoblasts was reduced in the Sall1 Cre:AR(L-/Y) mutant embryos, and the adult mutants were devoid of BC. The transition of myoblasts from proliferation to differentiation is mediated by cyclin-dependent kinase inhibitors. An increased expression of p21 was observed in the BC myoblast of the Sall1 Cre:AR(L-/Y) mutant and wild-type female. Altogether this study suggests that the nonmyocytic AR may paracrinely regulate the proliferation of myoblast possibly through inhibiting p21 expression in myoblasts of the BC.