Glia maturation factor beta deficiency protects against diabetic osteoporosis by suppressing osteoclast hyperactivity

Activation of megakaryocytic leukemia 1 in endothelial cells contributes to diabetic retinopathy in mice

AIMS

Diabetic retinopathy (DR) represents one of the most devastating sequences in patients with diabetes. Endothelial dysfunction is a key pathological feature of and contributing factor to DR. In the present study we investigated the role of megakaryocytic leukemia 1 (MKL1) in DR pathogenesis.

METHODS AND MATERIALS

DR was induced in mice by feeding with a high-fat diet (HFD). The Mkl1-Rosa26-KI mice were crossed to the Cdh5-CreERT2 mice to generate endothelial-specific MKL1 knock-in mice (MKL1EC-KI).

KEY FINDINGS

In cultured human primary retinal endothelial cells exposure to high glucose promoted nuclear translocation of MKL1 without altering its mRNA or protein expression. MKL1 knockdown ameliorated whereas MKL1 over-expression exacerbated high glucose induced impairment of endothelial barrier function. Compared to wild type littermates, MKL1EC-KI mice fed on HFD displayed worsened insulin resistance and accelerated DR pathogenesis. Consistently, administration of an MKL1 inhibitor CCG-1423 protected the mice from HFD feeding induced metabolic disorders and DR pathogenesis.

SIGNIFICANCE

Our data demonstrate that MKL1 may contribute to diabetic retinopathy by regulating endothelial behavior. Targeting MKL1 with small-molecule inhibitors can be considered as a therapeutic solution for the treatment of diabetic retinopathy.

Preliminary Mechanism of Glial Maturation Factor β on Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension

Recent evidence suggests that glia maturation factor β (GMFβ) is important in the pathogenesis of pulmonary arterial hpertension (PAH), but the underlying mechanism is unknown. To clarify whether GMFβ can be involved in pulmonary vascular remodeling and to explore the role of the IL-6-STAT3 pathway in this process, the expression of GMFβ in PAH rats is examined and the expression of downstream molecules including periostin (POSTN) and interleukin-6 (IL-6) is measured using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The location and expression of POSTN is also tested in PAH rats using immunofluorescence. It is proved that GMFβ is upregulated in the lungs of PAH rats. Knockout GMFβ alleviated the MCT-PAH by reducing right ventricular systolic pressure (RVSP), mean pulmonary arterial pressure (mPAP), and pulmonary vascular remodeling. Moreover, the inflammation of the pulmonary vasculature is ameliorated in PAH rats with GMFβ absent. In addition, the IL-6-STAT3 signaling pathway is activated in PAH; knockout GMFβ reduced POSTN and IL-6 production by inhibiting the IL-6-STAT3 signaling pathway. Taken together, these findings suggest that knockout GMFβ ameliorates PAH in rats by inhibiting the IL-6-STAT3 signaling pathway.