ICAM-1 regulates differentiation of MSC to adipocytes via activating MAPK pathway / 中国实验血液学杂志

This study was aimed to explore the molecular mechanism of the regulatory effects of ICAM-1 on the differentiation of mesenchymal stem cells (MSC) to adipocytes. The murine MSC cell line C3H10T 1/2 was treated with the supernatants contained plasmid MIGR1-ICAM-1 and MIGR1-ICAM-1/MSC (high expression of ICAM-1), the activation of the pathway was detected by Western blot. The ICAM-1 modified MSC and its control cells named MIGR1/MSC were cultured in adipocyte medium with or without the inhibitors of the ERK, P38, and JNK pathway. Oil-red-O staining was used to detect the lipid accumulation, and the expression of C/EBPα and PPARγ in differentiation of MSC to adipocyte were examined by real-time-PCR. The results showed that the overexpression of ICAM-1 stably activated the ERK, P38, and JNK pathway in MSC. Inhibiting of the activation of ERK pathways by chemical inhibitors up-regulated the mRNA expression level of C/EBPα and PPARγ in MIGR1-ICAM-1/MSC while inhibiting of P38 pathway resulted in lower mRNA expression of the transcription factors. Consistent with the mRNA expression, the lipid droplets were getting smaller and number of adipocytes increased when P38 pathway was inhibited, while bigger lipid droplet and increased quantity of adipocytes were identified in MIGR1-ICAM-1/MSC with the addition of ERK pathway inhibitor. It is concluded that ICAM-1 may suppress MSC differentiate into adipocyte via activating ERK pathway, while it can maintain the adipogenesis of MSC though P38 pathway.

Latest advances of studies on microRNA regulation in dendritic cells / 中国实验血液学杂志

MicroRNAs (miRNAs) are small, single-stranded and noncoding RNA molecules of about 22 nucleotides (nt) in length that regulate mRNA by binding to 3' untranslated regions (3'UTR) of target mRNA, inducing digestion, degradation and/or translational repression of the latter. Posttranscriptional regulation of gene expression by miRNA is critical for a wide range of physiologic and pathologic processes, including cell proliferation, differentiation, apoptosis, development and oncogenesis. Dendritic cells (DC) are professional antigen presenting cells that have a pivotal role in controlling immune responses. The latest studies indicated that miRNA are indispensable in regulation of development, differentiation and functions of DC. This review discusses the latest studies of miRNA controlling DC biological properties in order to deep understand the regulatory mechanism of DC, therefore, provide a new thinking for the therapeutic strategies of DC-associated immunological disorders.

Effects of ICAM-1 gene transfection on the adipogenic differentiation of MSCs / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of ICAM-1 gene transfection on the differentiation of MSCs to adipocytes.</p><p><b>METHODS</b>The recombinant retroviral expression plasmid MIGR1-ICAM-1 containing full length of mouse ICAM-1 gene was constructed. The constructed plasmid MIGR1-ICAM-1, empty plasmid MIGR1 and packaging plasmid ECOS were transfected into T293 cell lines and then the supernatant generated from T293 cells were used to infect mouse MSCs cell line C3H10T 1/2. The transfective efficiency was determined by inverted fluorescence microscope, real-time PCR and flow cytometry. Furthermore, ICAM-1 overexpressing MSCs (C3H10T 1/2-ICAM-1) and empty vector transfection MSCs (C3H10T 1/2-MIGR1) were cultured in medium with or without induction reagents, Oil-red-O staining was used to detect the lipid accumulation, and the expression of transcriptional factors C/EBPα and PPARγ, which were key factors in the differentiation of MSCs to adipocytes, were tested by real-time-PCR.</p><p><b>RESULTS</b>The recombinant retrovirus vector containing mouse ICAM-1 gene was successful constructed. After transfection into MSCs cell line C3H10T 1/2, the overexpression ICAM-1 MSCs cell line (C3H10T 1/2-ICAM-1) and control cell line (C3H10T 1/2-MIGR1) were obtained. Furthermore, these two cell lines were treated without or with adipocytic induction reagents, C3H10T 1/2-ICAM-1 showed significantly lower mRNA expression level for C/EBPα [(1.2 ± 0.7), (2.9 ± 0.9)] and PPARγ [(1557.6 ± 70.2), (7547.0 ± 442.2)] when compared with C3H10T 1/2-MIGR1 [(5.8 ± 0.5), (23.0 ± 2.3) and (2453.0 ± 215.6), (9856.3 ± 542.2)](P < 0.05). Moreover, little lipid droplet and decreased quantity of adipocytes were detected in C3H10T 1/2-ICAM-1 [(3.2 ± 0.5)/well, (12.2 ± 3.8)/well] than that in C3H10T 1/2-MIGR1 [(11.2 ± 0.4)/well, (51.3 ± 2.8)/well] (P < 0.05).</p><p><b>CONCLUSION</b>Overexpression of ICAM-1 in MSCs can inhibit its adipocytic differentiation.</p>

Effect of osteogenically and adipogenically differentiated bone mesenchymal stem cells from mouse on osteoclast formation / 中国实验血液学杂志

This study was purposed to investigate the regulatory effects of differentiating mesenchymal stem cells (MSC) on osteoclast formation. The MSC from mouse compact bones were cultured and induced into osteoblasts and adipocytes for one week. To test their regulatory effect on osteoclastogenesis, osteogenically differentiated and adipogenically differentiated MSC were co-cultured with CD11b(+) monocytes and osteoclasts were identified with in situ tartrate-resistant acid phosphatase (TRAP) staining. The results showed that differentiated MSC supported osteoclastogenesis but the osteoclast supporting capacity of osteogenically differentiated MSC decreased as compared with undifferentiated MSC. More interestingly, the adipogenically differentiated MSC significantly promoted osteoclasts formation when co-cultured with monocytes. It is concluded that the regulatory effect of MSC on osteoclast formation has changed while they have differentiated into different types of cells. The findings indicate that MSC may exert alternative effect on osteoclastogenesis by differentiation to descendant cells.