Luna-Acosta José Luis, Alba-Betancourt Clara, Martínez-Moreno Carlos G, Ramírez Candy, Carranza Martha, Luna Maricela, Arámburo Carlos
Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico.
Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico; Departamento de Farmacia, Universidad de Guanajuato, Guanajuato 36050, Mexico.
Gen Comp Endocrinol. 2015 Dec 1;224:148-59. doi: 10.1016/j.ygcen.2015.07.010. Epub 2015 Jul 29.
Growth hormone (GH) is expressed in several extra-pituitary tissues, including the primary and secondary lymphoid organs of the immune system. In birds, GH mRNA and protein expression show a specific developmental distribution pattern in the bursa of Fabricius (BF), particularly in epithelial and B cells. Changes in the bursal concentration and distribution of locally produced GH during ontogeny suggest it is involved in B cell differentiation and maturation, as well as in a functional survival role in this organ, which may be mediated by paracrine/autocrine mechanisms. Here, we analyzed the anti-apoptotic effect of GH in BF and the intracellular signaling pathways involved in this activity. Also, we studied if this effect was exerted directly by GH or mediated indirectly by IGF-I. Bursal cell cultures showed an important loss of their viability after 4h of incubation and a significant increase in apoptosis. However, treatment with 10nM GH or 40 nM IGF-I significantly increased B cell viability (16.7 ± 0.67% and 13.4 ± 1.12%, respectively) when compared with the untreated controls. In addition, the presence of apoptotic bodies (TUNEL) dramatically decreased (5.5-fold) after GH and IGF-I treatments, whereas co-incubation with anti-GH or anti-IGF-I, respectively, blocked their anti-apoptotic effect. Likewise, both GH and IGF-I significantly inhibited caspase-3 activity (by 40 ± 2.0%) in these cultures. However, the use of anti-IGF-I could not reverse the GH anti-apoptotic effects, thus indicating that these were exerted directly. The addition of 100 nM wortmannin (a PI3K/Akt inhibitor) blocked the GH protective effects. Also, GH stimulated (3-fold) the phosphorylation of Akt in bursal cells, and adding wortmannin or an anti-GH antibody inhibited this effect. Furthermore, GH was capable to stimulate (7-fold) the expression of Bcl-2. Taken together, these results indicate that the direct anti-apoptotic activity of GH observed in the chicken bursal B cell cultures might be mediated through the PI3K/Akt pathway.
生长激素（GH）在几种垂体外组织中表达，包括免疫系统的 primary 和 secondary 淋巴器官。在鸟类中，GH mRNA 和蛋白质表达在法氏囊（BF）中呈现特定的发育分布模式，特别是在上皮细胞和 B 细胞中。个体发育过程中，法氏囊中局部产生的 GH 的浓度和分布变化表明，它参与 B 细胞的分化和成熟，以及在该器官中的功能性存活作用，这可能由旁分泌/自分泌机制介导。在这里，我们分析了 GH 在 BF 中的抗凋亡作用以及参与此活动的细胞内信号通路。此外，我们研究了这种作用是由 GH 直接发挥的还是由 IGF-I 间接介导的。法氏囊细胞培养物在孵育 4 小时后显示其活力显著丧失，凋亡显著增加。然而，与未处理的对照相比，用 10nM GH 或 40nM IGF-I 处理显著提高了 B 细胞活力（分别为 16.7±0.67%和 13.4±1.12%）。此外，在 GH 和 IGF-I 处理后，凋亡小体（TUNEL）的数量显著减少（5.5 倍），而分别与抗 GH 或抗 IGF-I 共同孵育则阻断了它们的抗凋亡作用。同样，GH 和 IGF-I 均显著抑制了这些培养物中 caspase-3 的活性（降低 40±2.0%）。然而，使用抗 IGF-I 并不能逆转 GH 的抗凋亡作用，因此表明这些作用是直接发挥的。添加 100nM 渥曼青霉素（一种 PI3K/Akt 抑制剂）阻断了 GH 的保护作用。此外，GH 刺激（3 倍）了法氏囊细胞中 Akt 的磷酸化，添加渥曼青霉素或抗 GH 抗体抑制了这种作用。此外，GH 能够刺激（7 倍）Bcl-2 的表达。综上所述，这些结果表明，在鸡法氏囊 B 细胞培养物中观察到的 GH 的直接抗凋亡活性可能通过 PI3K/Akt 途径介导。
