Pathology

Biotechnology

Organic chemistry

Glycolysis

In vivo

Tendinopathy

Tendon

Biology

Endocrinology

Chemistry

Immunology

Angiogenesis

HIF1A

Wound healing

Metabolism

Cell biology

Cancer research

Oxygen

Anaerobic glycolysis

Medicine

Hypoxia (environmental)

Connective Tissue Research

Purpose/Aim of the study: Healthy tendons are maintained in homeostasis through controlled usage of glucose for energy and redox equilibrium. Tendon cell stress imposed by overuse injury or vascular insufficiency is accompanied by activation of wound healing pathways which facilitate an adaptive response and the restoration of homeostasis. To understand this response at the gene expression level we have studied the in vivo effects of injected TGF-β1 in a murine model of tendinopathy, as well as treatment of murine tendon explants with either TGF-β1 or hypoxia in vitro.We provide evidence (from expression patterns and immunohistochemistry) that both in vivo and in vitro, the stress response in tendon cells may be metabolically controlled in part by glycolytic reprogramming. A major feature of the response to TGF-β1 or hypoxia is activation of the Warburg pathway which generates lactate from glucose under normoxia and thereby inhibits mitochondrial energy production.We discuss the likely outcome of this major metabolic shift in terms of the potential benefits and damage to tendon and suggest how incorporation of this metabolic response into our understanding of initiation and progression of tendinopathies may offer new opportunities for diagnosis and the monitoring of therapies.

TGF-b1 or hypoxia enhance glucose metabolism and lactate production via HIF1A signaling in tendon cells