Identification and characterization of a rich population of CD34mesenchymal stem/stromal cells in human parotid, sublingual and submandibular glands

Mesenchymal stem/stromal cells (MSCs) play crucial roles in maintaining tissue homeostasis during physiological turnovers and injuries. Very little is known about the phenotype, distribution and molecular nature of MSCs in freshly isolated human salivary glands (SGs) as most reports have focused on the analysis of cultured MSCs. Our results demonstrate that the cell adhesion molecule CD34 was widely expressed by the MSCs of human major SGs, namely parotid (PAG), sublingual (SLG) and submandibular (SMG) glands. Further, gene expression analysis of CD34+ cells derived from fetal SMGs showed significant upregulation of genes involved in cellular adhesion, proliferation, branching, extracellular matrix remodeling and organ development. Moreover, CD34+ SMG cells exhibited elevated expression of genes encoding extracellular matrix, basement membrane proteins, and members of ERK, FGF and PDGF signaling pathways, which play key roles in glandular development, branching and homeostasis. In vitro CD34+ cell derived SG-MSCs revealed multilineage differentiation potential. Intraglandular transplantation of cultured MSCs in immunodeficient mice led to their engraftment in the injected and uninjected contralateral and ipsilateral glands. Engrafted cells could be localized to the stroma surrounding acini and ducts. In summary, our data show that CD34+ derived SG-MSCs could be a promising cell source for adoptive cell-based SG therapies, and bioengineering of artificial SGs

A Novel Nonsense Mutation in the DMP1 Gene Identified by a Genome-Wide Association Study Is Responsible for Inherited Rickets in Corriedale Sheep

Inherited rickets of Corriedale sheep is characterized by decreased growth rate, thoracic lordosis and angular limb deformities. Previous outcross and backcross studies implicate inheritance as a simple autosomal recessive disorder. A genome wide association study was conducted using the Illumina OvineSNP50 BeadChip on 20 related sheep comprising 17 affected and 3 carriers. A homozygous region of 125 consecutive single-nucleotide polymorphism (SNP) loci was identified in all affected sheep, covering a region of 6 Mb on ovine chromosome 6. Among 35 candidate genes in this region, the dentin matrix protein 1 gene (DMP1) was sequenced to reveal a nonsense mutation 250C/T on exon 6. This mutation introduced a stop codon (R145X) and could truncate C-terminal amino acids. Genotyping by PCR-RFLP for this mutation showed all 17 affected sheep were “T T” genotypes; the 3 carriers were “C T”; 24 phenotypically normal related sheep were either “C T” or “C C”; and 46 unrelated normal control sheep from other breeds were all “C C”. The other SNPs in DMP1 were not concordant with the disease and can all be ruled out as candidates. Previous research has shown that mutations in the DMP1 gene are responsible for autosomal recessive hypophosphatemic rickets in humans. Dmp1_knockout mice exhibit rickets phenotypes. We believe the R145X mutation to be responsible for the inherited rickets found in Corriedale sheep. A simple diagnostic test can be designed to identify carriers with the defective “T” allele. Affected sheep could be used as animal models for this form of human rickets, and for further investigation of the role of DMP1 in phosphate homeostasis

Human cytomegalovirus alters interleukin-6 production by endothelial cells

In an effort to study whether human cytomegalovirus (HCMV) can disrupt the balanced cytokine network that controls human hematopoiesis, we investigated the ability of a laboratory strain HCMV (AD169) to alter the production of interleukin-6 (IL-6) by cultured endothelial cells (HUVECs). ECs are important components of human bone marrow stroma and produce factors that stimulate the proliferation and differentiation of human hematopoietic progenitors. HCMV was able to greatly increase production of both mRNA and protein for IL-6 in unprimed HUVECs. When we discriminated between viral pellet and cleared viral supernatants, the supernatants induced an increase in mRNA at 30 minutes and protein by 2 hours, whereas an increase in IL-6 caused by virus itself did not become evident until 12 hours. The possibility that IL-6 induction was simply caused by the presence in the viral stock of endotoxin, IL-1 alpha, IL-1 beta, tumor necrosis factor alpha, or IL-4, all known inducers of IL-6 in HUVECs, was ruled out by the addition of polymyxin B and appropriate neutralizing antibodies. These findings show that HCMV is capable of directly and indirectly modulating the production by HUVECs of IL-6, one of the cytokines involved in the process of hematopoiesis.</jats:p

Human cytomegalovirus alters interleukin-6 production by endothelial cells

Abstract In an effort to study whether human cytomegalovirus (HCMV) can disrupt the balanced cytokine network that controls human hematopoiesis, we investigated the ability of a laboratory strain HCMV (AD169) to alter the production of interleukin-6 (IL-6) by cultured endothelial cells (HUVECs). ECs are important components of human bone marrow stroma and produce factors that stimulate the proliferation and differentiation of human hematopoietic progenitors. HCMV was able to greatly increase production of both mRNA and protein for IL-6 in unprimed HUVECs. When we discriminated between viral pellet and cleared viral supernatants, the supernatants induced an increase in mRNA at 30 minutes and protein by 2 hours, whereas an increase in IL-6 caused by virus itself did not become evident until 12 hours. The possibility that IL-6 induction was simply caused by the presence in the viral stock of endotoxin, IL-1 alpha, IL-1 beta, tumor necrosis factor alpha, or IL-4, all known inducers of IL-6 in HUVECs, was ruled out by the addition of polymyxin B and appropriate neutralizing antibodies. These findings show that HCMV is capable of directly and indirectly modulating the production by HUVECs of IL-6, one of the cytokines involved in the process of hematopoiesis.</jats:p