Presence of cartilage stem/progenitor cells in adult mice auricular perichondrium

Background

Based on evidence from several other tissues, cartilage stem/progenitor cells in the auricular cartilage presumably contribute to tissue development or homeostasis of the auricle. However, no definitive studies have identified or characterized a stem/progenitor population in mice auricle.

Methodology/Principal Findings

The 5-bromo-2′-deoxyuridine (BrdU) label-retaining technique was used to label dividing cells in fetal mice. Observations one year following the labeling revealed that label-retaining cells (LRCs) were present specifically in auricular perichondrium at a rate of 0.08±0.06%, but LRCs were not present in chondrium. Furthermore, LRCs were successfully isolated and cultivated from auricular cartilage. Immunocytochemical analyses showed that LRCs express CD44 and integrin-α₅. These LRCs, putative stem/progenitor cells, possess clonogenicity and chondrogenic capability in vitro.

Conclusions/Significance

We have identified a population of putative cartilage stem/progenitor cells in the auricular perichondrium of mice. Further characterization and utilization of the cell population should improve our understanding of basic cartilage biology and lead to advances in cartilage tissue engineering and novel therapeutic strategies for patients with craniofacial defects, including long-term tissue restoration.     

Transplantation of bone marrow-derived mononuclear cells improves mechanical hyperalgesia, cold allodynia and nerve function in diabetic neuropathy

Relief from painful diabetic neuropathy is an important clinical issue. We have previously shown that the transplantation of cultured endothelial progenitor cells or mesenchymal stem cells ameliorated diabetic neuropathy in rats. In this study, we investigated whether transplantation of freshly isolated bone marrow-derived mononuclear cells (BM-MNCs) alleviates neuropathic pain in the early stage of streptozotocin-induced diabetic rats. Two weeks after STZ injection, BM-MNCs or vehicle saline were injected into the unilateral hind limb muscles. Mechanical hyperalgesia and cold allodynia in SD rats were measured as the number of foot withdrawals to von Frey hair stimulation and acetone application, respectively. Two weeks after the BM-MNC transplantation, sciatic motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), sciatic nerve blood flow (SNBF), mRNA expressions and histology were assessed. The BM-MNC transplantation significantly ameliorated mechanical hyperalgesia and cold allodynia in the BM-MNC-injected side. Furthermore, the slowed MNCV/SNCV and decreased SNBF in diabetic rats were improved in the BM-MNC-injected side. BM-MNC transplantation improved the decreased mRNA expression of NT-3 and number of microvessels in the hind limb muscles. There was no distinct effect of BM-MNC transplantation on the intraepidermal nerve fiber density. These results suggest that autologous transplantation of BM-MNCs could be a novel strategy for the treatment of painful diabetic neuropathy.     

Cloning and structural analysis of bglM gene coding for the fungal cell wall-lytic beta-1,3-glucan-hydrolase BglM of Bacillus circulans IAM1165

Bacillus circulans IAM1165 produces isoforms of beta-1,3-glucan-hydrolases. Of these enzymes, the 42-kDa enzyme BgIM degrades Aspergillus oryzae cell walls the most actively. A gene coding for a BgIM precursor consisting of 411 amino acid residues was cloned. The 27 N-terminal amino acid sequence of the precursor is a signal peptide. The 141 C-terminal amino acid sequence showed a motif of carbohydrate-binding module family 13. This domain bound to pachyman, lichenan, and A. oryzae cell walls. The central domain showed a bacterial beta-1,3-glucan-hydrolase motif belonging to glycosyl hydrolase family 16. By removal of the C-terminal domain in the IAM1165 culture, mature BglM was processed to several 27-kDa fragments that hydrolyze a soluble beta-1,3-glucan.     

Herpes Simplex Virus-Induced Expression of 70 kDa Heat Shock Protein (HSP70) Requires Early Protein Synthesis But Not Viral DNA Replication

The major 70 kDa heat shock protein (HSP70), which is scarcely expressed in unstressed rodent cells, was apparently induced by infection with herpes simplex virus (HSV). Infection with HSV types 1 and 2 elevated HSP70 mRNA levels within 4 hr post-infection. HSP70 synthesis and accumulation increased in HSV-infected cells. Irradiation of HSV with UV-light abolished the ability to induce HSP70 mRNA. Inhibitors of viral DNA synthesis did not affect the induction of HSP70 in infected cells. Protein synthesis within 2 hr after infection was necessary for HSP70 induction.     

<Emphasis Type="Italic">cis</Emphasis>-Cinnamoyl Glucoside as a Major Plant Growth Inhibitor Contained in <Emphasis Type="Italic">Spiraea prunifolia</Emphasis>

Crude extracts of the leaves of Spiraea prunifolia Sieb. showed high plant-growth-inhibiting activity comparable to that of S. thunbergii extracts. To isolate the causal compound in S. prunifolia, we performed bioassay-directed purification by monitoring the biological activity per unit weight of the organism containing the bioactive compound (total activity). We isolated 1-O-cis-cinnamoyl-β-D-glucopyranose (cis-CG) and identified it as the most important growth-inhibiting constituent in the crude extracts. We did not detect 6-O-(4′-hydroxy-2′-methylenebutyroyl)-1-O-cis-cinnamoyl-β-D-glucopyranose (cis-BCG) in S. prunifolia, though it is a major plant growth inhibitor in S. thunbergii together with cis-CG. We estimated the cis-CG content in S. prunifolia to be 3.84 mmol kg⁻¹ F.W. This amount is comparable to the cis-CG plus cis-BCG content in S. thunbergii (3.59 mmol kg⁻¹ F.W.). This indicates that S. prunifolia and S. thunbergii have equally high potential to inhibit plant growth, and cis-CG acts as the most important plant-growth inhibitor in S. prunifolia extracts.     

HIV budding and Tsg101

HIV, as well as many enveloped viruses, exits the cells by budding directly from the plasma membrane. HIV budding is dependent on a PTAP motif, which is located within the p6 domain of Gag. Recent studies have shown that the cellular protein Tsg101 binds to the PTAP L-domain motif of HIV p6 and facilitates the final stages of virus release. Tsg101 function in the cellular vacuolar protein sorting pathway, where they play central roles in selecting cargo for incorporation into vesicles that bud into the maturing endosome to create multivesicular bodies (MVBs). Vesicle budding into the MVB and viral budding at the plasma membrane are topologically equivalent, and the same machinery could catalyze both processes. It will be important to understand the mechanism of virus budding in detail, since virus budding may be a potential target for interference with HIV propagation.     

Somatostatin regulates brain amyloid beta peptide Abeta42 through modulation of proteolytic degradation

Expression of somatostatin in the brain declines during aging in various mammals including apes and humans. A prominent decrease in this neuropeptide also represents a pathological characteristic of Alzheimer disease. Using in vitro and in vivo paradigms, we show that somatostatin regulates the metabolism of amyloid beta peptide (Abeta), the primary pathogenic agent of Alzheimer disease, in the brain through modulating proteolytic degradation catalyzed by neprilysin. Among various effector candidates, only somatostatin upregulated neprilysin activity in primary cortical neurons. A genetic deficiency of somatostatin altered hippocampal neprilysin activity and localization, and increased the quantity of a hydrophobic 42-mer form of Abeta, Abeta(42), in a manner similar to presenilin gene mutations that cause familial Alzheimer disease. These results indicate that the aging-induced downregulation of somatostatin expression may be a trigger for Abeta accumulation leading to late-onset sporadic Alzheimer disease, and suggest that somatostatin receptors may be pharmacological-target candidates for prevention and treatment of Alzheimer disease.