Beta2-microglobulin as a potential factor for the expansion of mesenchymal stem cells

β2-microglobulin is overexpressed in buccal cells of elderly and correlated with expression of p16 and inflammatory genes

β2M (Beta 2 microglobulin) is a small protein that is found in all nucleated cells, previous finding showed that its levels increased in the serum of the elderly. Buccal cell samples are none invasive approach for assessing the expression of target genes. There was rationality to assess the expression of β2M in buccal cells of people of a different group of ages. Indeed, the expression of β2M increased significantly with fold change 3.40, 4.80, 6.60^**, 8.20^*** and 12.04^*** for the group of age 18–25 years, 26–35 years, 36–45 years, 46–55 years, and 56–70 years respectively. The same observation was seen with markers of biological aging (p16^INK4a) with fold change 3.19, 3.90, 4.80*, 8.50^*** and 12.40^*** for the group of age 18–25 years, 26–35 years, 36–45 years, 46–55 years, and 56–70 years respectively. As expected, there was an increase in the inflammatory genes (IL-1 β and IL-6) expression in the elderly. Moreover, there was a direct significant correlation (r = 90, p < 0.001) between β2M expression and age (years), and the same direct significant correlation between p16^INK4a expression and age (years) was also seen (r = 90, p < 0.001). In addition, a direct correlation between β2M and p16^INK4a was also seen (r = 0.8.3, p < 0.001), there was also direct correlation between β2M and IL-1 β and IL-6 with (r = 0.5, p < 0.001; r = 0.68, p < 0.001) respectively. This evidence showed that β2M increased in buccal cells of the elderly compared to younger, and thereby buccal cells can be exploited to assess biological aging by measuring β2M levels, however, large sample size and using another assessing method such as β2M protein levels should be performed to confirm the results.

Beta 2 microglobulin correlates with oxidative stress in elderly

Beta 2 microglobulin (Β2M) is expressed in all nucleated cells, it interplays with mediators to regulate and modulate cellular functions. Its role in aging associated disorders has been documented recently. Oxidative stress has been known to play a direct implication on these disorders. Therefore, there is a rationality to explore the function of Β2M in oxidative stress in elderly people. The aim of the study was to assess the Β2M levels in different group of age, and to study the correlation between Β2M and oxidative stress. Actually, the serum levels of Β2M increased significantly in old people comparing to youngers. In addition, there was a positive correlation between Β2M levels and the age of participants (p < 0.001). In addition, there was a positive correlation between Β2M levels and Malondialdehyde (MDA) (p < 0.001), which underscored the possible role of Β2M in oxidative stress. To confirm the previous result, the correlation between total antioxidant capacity (TAC) and Β2M was assessed. There was a negative correlation between them (p < 0.001). These results suggested a possible role of Β2M in oxidative stress status in elderly people; in addition, it suggested the ability of using Β2M as a novel biomarker for oxidative stress. However, further work should be conducted to explore the exact role of Β2M in oxidative stress, and to include large sample size to confirm the results before translating the findings to clinic.

GAPDH, β-actin and β2-microglobulin, as three common reference genes, are not reliable for gene expression studies in equine adipose- and marrow-derived mesenchymal stem cells

Background

Quantitative real time reverse transcription PCR (qRT-PCR) is one of the most important techniques for gene-expression analysis in molecular based studies. Selecting a proper internal control gene for normalizing data is a crucial step in gene expression analysis via this method. The expression levels of reference genes should be remained constant among cells in different tissues. However, it seems that the location of cells in different tissues might influence their expression. The purpose of this study was to determine whether the source of mesenchymal stem cells (MSCs) has any effect on expression level of three common reference genes (GAPDH, β-actin and β2-microglobulin) in equine marrow- and adipose- derived undifferentiated MSCs and consequently their reliability for comparative qRT-PCR.

Materials and methods

Adipose tissue (AT) and bone marrow (BM) samples were harvested from 3 mares. MSCs were isolated and cultured until passage 3 (P3). Total RNA of P3 cells was extracted for cDNA synthesis. The generated cDNAs were analyzed by quantitative real-time PCR. The PCR reactions were ended with a melting curve analysis to verify the specificity of amplicon.

Results

The expression levels of GAPDH were significantly different between AT- and BM- derived MSCs (p < 0.05). Differences in expression level of β-actin (P < 0.001) and B2M (P < 0.006.) between MSCs derived from AT and BM were substantially higher than GAPDH. In addition, the fold change in expression levels of GAPDH, β-actin and B2M in AT-derived MSCs compared to BM-derived MSCs were 2.38, 6.76 and 7.76, respectively.

Conclusion

This study demonstrated that GAPDH and especially β-actin and B2M express in different levels in equine AT- and BM- derived MSCs. Thus they cannot be considered as reliable reference genes for comparative quantitative gene expression analysis in MSCs derived from equine bone marrow and adipose tissue.

β2-Microglobulin-mediated signaling as a target for cancer therapy

β2-microglobulin (β2-m) has become the focus of intense scrutiny since the discovery of its undesirable roles promoting osteomimicry and cancer progression. β2-m is a well-known housekeeping protein that forms complexes with the heavy chain of major histocompatibility complex class I molecules, which are heterodimeric cell surface proteins that present antigenic peptides to cytotoxic T cells. On recognition of foreign peptide antigens on cell surfaces, T cells actively bind and lyse antigen-presenting cancer cells. In addition to its roles in tumor immunity, β2-m has two different functions in cancer cells, either tumor promoting or tumor suppressing, in cancer cell context-dependent manner. Our studies have demonstrated that β2-m is involved extensively in the functional regulation of growth, survival, apoptosis, and even metastasis of cancer cells. We found that β2-m is a soluble growth factor and a pleiotropic signaling molecule which interacts with its receptor, hemochromatosis protein, to modulate epithelial-to-mesenchymal transition (EMT) through iron-responsive pathways. Specific antibodies against β2-m have remarkable tumoricidal activity in cancer, through β2-m action on iron flux, alterations of intracellular reactive oxygen species, DNA damage and repair enzyme activities, β-catenin activation and cadherin switching, and tumor responsiveness to hypoxia. These novel functions of β2-m and β2-m signaling may be common to several solid tumors including human lung, breast, renal, and prostate cancers. Our experimental results could lead to the development of a novel class of antibody-based pharmaceutical agents for cancer growth control. In this review, we briefly summarize the recent data regarding β2-m as a promising new cancer therapeutic target and discuss antagonizing this therapeutic target with antibody therapy for the treatment of localized and disseminated cancers.

β2-microglobulin induces epithelial to mesenchymal transition and confers cancer lethality and bone metastasis in human cancer cells

Bone metastasis is one of the predominant causes of cancer lethality. This study demonstrates for the first time how β2-microglobulin (β2-M) supports lethal metastasis in vivo in human prostate, breast, lung, and renal cancer cells. β2-M mediates this process by activating epithelial to mesenchymal transition (EMT) to promote lethal bone and soft tissue metastases in host mice. β2-M interacts with its receptor, hemochromatosis (HFE) protein, to modulate iron responsive pathways in cancer cells. Inhibition of either β2-M or HFE results in reversion of EMT. These results demonstrate the role of β2-M in cancer metastasis and lethality. Thus, β2-M and its downstream signaling pathways are promising prognostic markers of cancer metastases and novel therapeutic targets for cancer therapy.

Differences in gene expression dependent on sampling site in placental tissue of fetuses with intrauterine growth restriction

OBJECTIVE

The human placenta as part of the feto-placental unit may influence fetal endocrine systems and may therefore represent a very important link between intrauterine growth restriction (IUGR) and metabolic disorders in later life. We aimed to analyze the effect of sample origin on gene expression of placental factors potentially involved in fetal programming in IUGR versus appropriate for gestational age growth (AGA) to standardize sample collection procedure for a multicenter approach.

DESIGN

Placental gene expression of insulin-like growth factor-binding protein (IGFBP)-1, prolactin, corticotropin releasing hormone (CRH) and leptin was measured and compared between proximal, intermediate and peripheral region of the placenta in 22 IUGR (proven by anomalous placental Doppler velocimetry) and 19 AGA neonates.

RESULTS

Whereas no difference in gene expression was seen in the proximal portion, in the intermediate placental region mRNA expression of IGFBP-1 (p = 0.01), prolactin (p = 0.04), CRH (p = 0.01) and leptin (p = 0.04) was increased in IUGR samples compared to controls. At the placental periphery, gene expression of these placental transcripts showed a higher expression level in IUGR placentas without statistical significance, except for leptin (p = 0.03).

CONCLUSION

Placental sampling site seems to be relevant for detecting differences in gene expression between IUGR and AGA neonates.