Purified Human Synovium Mesenchymal Stem Cells as a Good Resource for Cartilage Regeneration

Mesenchymal stem cells (MSCs) have the ability to differentiate into a variety of lineages and to renew themselves without malignant changes, and thus hold potential for many clinical applications. However, it has not been well characterized how different the properties of MSCs are depending on the tissue source in which they resided. We previously reported a novel technique for the prospective MSC isolation from bone marrow, and revealed that a combination of cell surface markers (LNGFR and THY-1) allows the isolation of highly enriched MSC populations. In this study, we isolated LNGFR⁺ THY-1 ⁺ MSCs from synovium using flow cytometry. The results show that the synovium tissue contained a significantly larger percentage of LNGFR ⁺ THY-1 ⁺ MSCs. We examined the colony formation and differentiation abilities of bone marrow-derived MSCs (BM-MSCs) and synovium-derived MSCs (SYN-MSCs) isolated from the same patients. Both types of MSCs exhibited a marked propensity to differentiate into specific lineages. BM-MSCs were preferentially differentiated into bone, while in the SYN-MSC culture, enhanced adipogenic and chondrogenic differentiation was observed. These data suggest that the tissue from which MSCs are isolated should be tailored according to their intended clinical therapeutic application.     

Differences in Gait Characteristics of Patients with Lumbar Spinal Canal Stenosis (L4 Radiculopathy) and Those with Osteoarthritis of the Hip

It is important to differentially diagnose thigh pain from lumbar spinal stenosis (particularly lumbar fourth nerve root radiculopathy) and osteoarthritis of the hip. In this study, using a treadmill and a motion analysis method, gait characteristics were compared between these conditions. Patients with lumbar fourth nerve root radiculopathy had increased physiological knee flexion immediately after foot-ground contact, possibly owing to a slight decrease in the muscle strength of the quadriceps femoris muscle. Patients with osteoarthritis of the hip had decreased range of motion of the hip joint probably due to anatomically limited mobility as well as gait strategy to avoid pain resulting from increased internal pressure on the hip joint during its extension. Our facile and noninvasive method can be useful for the differential diagnosis of lumbar spinal canal stenosis from osteoarthritis of the hip.     

Extracellular Matrix and Growth Factors Improve the Efficacy of Intramuscular Islet Transplantation

BackgroundThe efficacy of intramuscular islet transplantation is poor despite being technically simple, safe, and associated with reduced rates of severe complications. We evaluated the efficacy of combined treatment with extracellular matrix (ECM) and growth factors in intramuscular islet transplantation.MethodsMale BALB/C mice were used for the in vitro and transplantation studies. The following three groups were evaluated: islets without treatment (islets-only group), islets embedded in ECM with growth factors (Matrigel group), and islets embedded in ECM without growth factors [growth factor-reduced (GFR) Matrigel group]. The viability and insulin-releasing function of islets cultured for 96 h were significantly improved in Matrigel and GFR Matrigel groups compared with the islets-only group.ResultsBlood glucose and serum insulin levels immediately following transplantation were significantly improved in the Matrigel and GFR Matrigel groups and remained significantly improved in the Matrigel group at postoperative day (POD) 28. On histological examination, significantly decreased numbers of TdT-mediated deoxyuridine triphosphate-biotin nick end labeling-positive islet cells and significantly increased numbers of Ki67-positive cells were observed in the Matrigel and GFR Matrigel groups at POD 3. Peri-islet revascularization was most prominent in the Matrigel group at POD 14.ConclusionsThe efficacy of intramuscular islet transplantation was improved by combination treatment with ECM and growth factors through the inhibition of apoptosis, increased proliferation of islet cells, and promotion of revascularization.     

Autologous Transplantation of Oral Mucosal Epithelial Cell Sheets Cultured on an Amniotic Membrane Substrate for Intraoral Mucosal Defects

The human amniotic membrane (AM) is a thin intrauterine placental membrane that is highly biocompatible and possesses anti-inflammatory and anti-scarring properties. Using AM, we developed a novel method for cultivating oral mucosal epithelial cell sheets. We investigated the autologous transplantation of oral mucosal epithelial cells cultured on AM in patients undergoing oral surgeries. We obtained specimens of AM from women undergoing cesarean sections. This study included five patients without any history of a medical disorder who underwent autologous cultured oral epithelial transplantation following oral surgical procedures. Using oral mucosal biopsy specimens obtained from these patients, we cultured oral epithelial cells on an AM carrier. We transplanted the resultant cell sheets onto the oral mucosal defects. Patients were followed-up for at least 12 months after transplantation. After 2–3 weeks of being cultured on AM, epithelial cells were well differentiated and had stratified into five to seven layers. Immunohistochemistry revealed that the cultured cells expressed highly specific mucosal epithelial cell markers and basement membrane proteins. After the surgical procedures, no infection, bleeding, rejection, or sheet detachment occurred at the reconstructed sites, at which new oral mucous membranes were evident. No recurrence was observed in the long-term follow-up, and the postoperative course was excellent. Our results suggest that AM-cultured oral mucosal epithelial cell sheets represent a useful biomaterial and feasible method for oral mucosal reconstruction. However, our primary clinical study only evaluated their effects on a limited number of small oral mucosal defects.     

Structural organization of nuclear lamins A,C, B1, and B2 revealed by superresolution microscopy

The nuclear lamina is a key structural element of the metazoan nucleus. However, the structural organization of the major proteins composing the lamina is poorly defined. Using three-dimensional structured illumination microscopy and computational image analysis, we characterized the supramolecular structures of lamin A, C, B1, and B2 in mouse embryo fibroblast nuclei. Each isoform forms a distinct fiber meshwork, with comparable physical characteristics with respect to mesh edge length, mesh face area and shape, and edge connectivity to form faces. Some differences were found in face areas among isoforms due to variation in the edge lengths and number of edges per face, suggesting that each meshwork has somewhat unique assembly characteristics. In fibroblasts null for the expression of either lamins A/C or lamin B1, the remaining lamin meshworks are altered compared with the lamin meshworks in wild-type nuclei or nuclei lacking lamin B2. Nuclei lacking LA/C exhibit slightly enlarged meshwork faces and some shape changes, whereas LB1-deficient nuclei exhibit primarily a substantial increase in face area. These studies demonstrate that individual lamin isoforms assemble into complex networks within the nuclear lamina and that A- and B-type lamins have distinct roles in maintaining the organization of the nuclear lamina.     

How did bonobos come to range south of the congo river? Reconsideration of the divergence of Pan paniscus from other Pan populations

While investigating the genetic structure in wild bonobos,¹ we realized that the widely accepted scenario positing that the Pleistocene appearance of the Congo River separated the common ancestor of chimpanzees (Pan troglodytes) and bonobos (P. paniscus) into two species is not supported by recent geographical knowledge about the formation of the Congo River. We explored the origin of bonobos using a broader biogeographical perspective by examining local faunas in the central African region. The submarine Congo River sediments and paleotopography of central Africa show that the Congo River has functioned as a geographical barrier for the last 34 million years. This evidence allows us to hypothesize that when the river was first formed, the ancestor of bonobos did not inhabit the current range of the species on the left bank of the Congo River but that, during rare times when the Congo River discharge decreased during the Pleistocene, one or more founder populations of ancestral Pan paniscus crossed the river to its left bank. The proposed scenario for formation of the Congo River and the corridor hypothesis for an ancestral bonobo population is key to understanding the distribution of great apes and their evolution.     

Structural basis for acceptor‐substrate recognition of UDP‐glucose: anthocyanidin 3‐O‐glucosyltransferase from Clitoria ternatea

UDP‐glucose: anthocyanidin 3‐O‐glucosyltransferase (UGT78K6) from Clitoria ternatea catalyzes the transfer of glucose from UDP‐glucose to anthocyanidins such as delphinidin. After the acylation of the 3‐O‐glucosyl residue, the 3′‐ and 5′‐hydroxyl groups of the product are further glucosylated by a glucosyltransferase in the biosynthesis of ternatins, which are anthocyanin pigments. To understand the acceptor‐recognition scheme of UGT78K6, the crystal structure of UGT78K6 and its complex forms with anthocyanidin delphinidin and petunidin, and flavonol kaempferol were determined to resolutions of 1.85 Å, 2.55 Å, 2.70 Å, and 1.75 Å, respectively. The enzyme recognition of unstable anthocyanidin aglycones was initially observed in this structural determination. The anthocyanidin‐ and flavonol‐acceptor binding details are almost identical in each complex structure, although the glucosylation activities against each acceptor were significantly different. The 3‐hydroxyl groups of the acceptor substrates were located at hydrogen‐bonding distances to the Nε2 atom of the His17 catalytic residue, supporting a role for glucosyl transfer to the 3‐hydroxyl groups of anthocyanidins and flavonols. However, the molecular orientations of these three acceptors are different from those of the known flavonoid glycosyltransferases, VvGT1 and UGT78G1. The acceptor substrates in UGT78K6 are reversely bound to its binding site by a 180° rotation about the O1–O3 axis of the flavonoid backbones observed in VvGT1 and UGT78G1; consequently, the 5‐ and 7‐hydroxyl groups are protected from glucosylation. These substrate recognition schemes are useful to understand the unique reaction mechanism of UGT78K6 for the ternatin biosynthesis, and suggest the potential for controlled synthesis of natural pigments.     

Genome-wide association mapping in a wild avian population identifies a link between genetic and phenotypic variation in a life-history trait

Understanding the genetic basis of traits involved in adaptation is a major challenge in evolutionary biology but remains poorly understood. Here, we use genome-wide association mapping using a custom 50 k single nucleotide polymorphism (SNP) array in a natural population of collared flycatchers to examine the genetic basis of clutch size, an important life-history trait in many animal species. We found evidence for an association on chromosome 18 where one SNP significant at the genome-wide level explained 3.9% of the phenotypic variance. We also detected two suggestive quantitative trait loci (QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were generally weak and not significant, although there was some indication of a sex-by-genotype interaction for lifetime reproductive success at the suggestive QTL on chromosome 26. This implies that sexual antagonism may play a role in maintaining genetic variation at this QTL. Our findings provide candidate regions for a classic avian life-history trait that will be useful for future studies examining the molecular and cellular function of, as well as evolutionary mechanisms operating at, these loci.     

Class I Myosins Have Overlapping and Specialized Functions in Left-Right Asymmetric Development in Drosophila

The class I myosin genes are conserved in diverse organisms, and their gene products are involved in actin dynamics, endocytosis, and signal transduction. Drosophila melanogaster has three class I myosin genes, Myosin 31DF (Myo31DF), Myosin 61F (Myo61F), and Myosin 95E (Myo95E). Myo31DF, Myo61F, and Myo95E belong to the Myosin ID, Myosin IC, and Myosin IB families, respectively. Previous loss-of-function analyses of Myo31DF and Myo61F revealed important roles in left–right (LR) asymmetric development and enterocyte maintenance, respectively. However, it was difficult to elucidate their roles in vivo, because of potential redundant activities. Here we generated class I myosin double and triple mutants to address this issue. We found that the triple mutant was viable and fertile, indicating that all three class I myosins were dispensable for survival. A loss-of-function analysis revealed further that Myo31DF and Myo61F, but not Myo95E, had redundant functions in promoting the dextral LR asymmetric development of the male genitalia. Myo61F overexpression is known to antagonize the dextral activity of Myo31DF in various Drosophila organs. Thus, the LR-reversing activity of overexpressed Myo61F may not reflect its physiological function. The endogenous activity of Myo61F in promoting dextral LR asymmetric development was observed in the male genitalia, but not the embryonic gut, another LR asymmetric organ. Thus, Myo61F and Myo31DF, but not Myo95E, play tissue-specific, redundant roles in LR asymmetric development. Our studies also revealed differential colocalization of the class I myosins with filamentous (F)-actin in the brush border of intestinal enterocytes.