The Presence and Distribution of TRPM7 in the Canine Mammary Glands

SIMPLE SUMMARY: Mammary gland tumors are one of the major causes of mortality in dogs. It is, therefore, imperative to clarify the nature of this disease. Transient receptor potential melastatin-subfamily member 7 (TRPM7), a bifunctional ion channel found in human cells, plays a role in normal physiological processes such as cell development, survival, proliferation, differentiation, and migration. However, TRPM7 is also active in several types of cancers in humans, and blocking the expression of this pathway leads to a decrease in the proliferation, migration, and invasion of cancer cells. We have proved the presence of TRPM7 in healthy canine mammary tissues, which could help further studies that aim to establish the relationship between TRPM7 and its physiological and pathophysiological effects in the canine mammary glands and, possibly, tumors. ABSTRACT: The transient receptor potential melastatin-subfamily member 7 (TRPM7) cation channel is a bifunctional ion channel with intrinsic kinase activity and is ubiquitously expressed in the animal/human body. Accumulated knowledge of TRPM7 suggests that it plays an essential role in normal physiological processes, including the development, survival, proliferation, differentiation, and migration of cells. The aim of this study was to demonstrate the presence and expression patterns of TRPM7 in normal canine mammary glands using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry. Normal mammary gland tissue samples were obtained from five female beagle dogs. RT-PCR and sequencing of the amplified PCR products demonstrated the presence of TRPM7 mRNA in normal mammary glands, and the presence of TRPM7 protein was confirmed by Western blotting. Immunohistochemical investigations demonstrated the expression of TRPM7 in the apical membrane of acinar and ductal epithelial cells in the canine mammary glands. These results provide the first evidence of the presence and distribution of TRPM7 in the canine mammary gland and could help explain the physiological and pathological roles of TRPM7 in the canine mammary gland; however, additional studies are required to elucidate these roles.