High expression of BCL6 inhibits the differentiation and development of hematopoietic stem cells and affects the growth and development of chickens

Abstract

Background B-cell CLL/lymphoma 6 (BCL6) is a transcriptional master regulator that represses more than 1200 potential target genes. Our previous study showed that a decline in blood production in runting and stunting syndrome (RSS) affected sex-linked dwarf (SLD) chickens compared to SLD chickens. However, the association between BCL6 gene and hematopoietic function remains unknown in chickens. Methods In this study, we used RSS affected SLD (RSS-SLD) chickens, SLD chickens and normal chickens as research object and overexpression of BCL6 in hematopoietic stem cells (HSCs), to investigate the effect of the BCL6 on differentiation and development of HSCs. Results The results showed that comparison of RSS-SLD chickens with SLD chickens, the BCL6 was highly expressed in RSS-SLD chickens bone marrow. The bone marrow of RSS-SLD chickens was exhausted and red bone marrow was largely replaced by yellow bone marrow, bone density was reduced, and the levels of immature erythrocytes in peripheral blood were increased. At the same time, the hematopoietic function of HSCs decreased in RSS-SLD chickens, which was manifested by a decrease in the hematopoietic growth factors (HGFs) EPO, SCF, TPO, and IL-3, as well as hemoglobin α1 and hemoglobin β expression. Moreover, mitochondrial function in the HSCs of RSS-SLD chickens was damaged, including an increase in ROS production, decrease in ATP concentration, and decrease in mitochondrial membrane potential (ΔΨm). The same results were also observed in SLD chickens compared with normal chickens; however, the symptoms were more serious in RSS-SLD chickens. Additionally, after overexpression of the BCL6 in primary HSCs, the secretion of HGFs (EPO, SCF, TPO and IL-3) was inhibited and the expression of hemoglobin α1 and hemoglobin β was decreased. However, cell proliferation was accelerated, apoptosis was inhibited, and the HSCs entered a cancerous state. The function of mitochondria was also abnormal, ROS production was decreased, and ATP concentration and ΔΨm were increased, which was related to the inhibition of apoptosis of stem cells. Conclusions Taken together, we conclude that the high expression of BCL6 inhibits the differentiation and development of HSCs by affecting mitochondrial function, resulting in impaired growth and development of chickens. Moreover, the abnormal expression of BCL6 might be a cause of the clinical manifestations of chicken comb, pale skin, stunted growth and development, and the tendency to appear RSS in SLD chickens.

Growth Hormone Receptor Controls Adipogenic Differentiation of Chicken Bone Marrow Mesenchymal Stem Cells by Affecting Mitochondrial Biogenesis and Mitochondrial Function

“…In this study, fat deposition in bone marrow tissue of 21-day-old SLD chickens was greater than that in normal chickens, consistent with previous findings ( Li et al, 2021 ). In addition, triglyceride content of bone marrow tissue in SLD chickens was twice as high as that in normal chickens, consistent with fat deposition.…”

“…Fat deposition is more severe in SLD chickens than in normal chickens (Guillaume, 1976). In a previous study, compared with normal chickens, red bone marrow was severely depleted and replaced by yellow bone marrow in 7-week-old SLD chickens (Li et al, 2021). It was hypothesized that the SLD phenotype was due to a functional deletion of the GHR gene.…”

miRNA-10a-5p Targeting the BCL6 Gene Regulates Proliferation, Differentiation and Apoptosis of Chicken Myoblasts

“…The BCL6 gene, a transcriptional regulator, is involved in the transcriptional regulation of more than 1200 genes and 14,000 proteins [ 33 , 34 ]. In vascular smooth muscle of hypertensive patients, overexpression of the BCL6 gene attenuated the expression of NADPH oxidase 4 (NOX4).…”

“…The BCL6 gene was discovered as an oncogene involved in the growth and development of B-cell lymphoma, which could contribute to the malignant phenotype by inhibiting DNA damage repair and blocking B-cell terminal differentiation [ 37 ]. In chicken bone marrow mesenchymal stem cells (MSCs), overexpression of the BCL6 gene inhibited the secretion of hematopoietic growth factors and blocked the differentiation of hematopoietic stem cells [ 33 ]. Expression of BCL6 in CD4+ T cells promoted follicular helper T cell (TFH) differentiation in mice [ 38 , 39 ].…”

“…Subsequently, the phenomenon that the BCL6 gene could inhibit cellular apoptosis was confirmed in the related functional validation [ 40 ]. In chicken hematopoietic stem cells, BCL6 also exerted an inhibitory effect on apoptosis [ 33 ]. In our study, the BCL6 gene inhibited the apoptosis of chicken myoblasts, which was consistent with previous studies.…”