Transient Receptor Potential Melastatin Type 7 Channel Is Critical for the Survival of Bone Marrow Derived Mesenchymal Stem Cells

Abstract

The transient receptor potential melastatin type 7 channel (TRPM7) is a member of the TRP family of ion channels that is essential for cell proliferation and viability. Mesenchymal stem cells (MSCs) from bone marrow are a potential source for tissue repair due to their ability to differentiate into specialized cells. However, the role of TRPM7 in stem cells is unknown. In this study, we characterized TRPM7 in mouse MSCs using molecular biology, immunocytochemistry, and patch clamp. We also investigated TRPM7 function using a lentiviral vector and specifi c shRNA to knockdown gene expression. By RT-PCR and immunocytochemistry, we identifi ed TRPM7, but not TRPM6, a close family member with similar function. Electrophysiological recordings during depletion of intracellular Mg 2+ or Mg 2+-ATP resulted in the development of currents typical for the channel. Furthermore, 2-aminoethoxydiphenyl borate (1 pM-100 μM) inhibited TRPM7 in a concentration-dependent manner. The molecular suppression of TRPM7 signifi cantly decreased MSC proliferation and viability as determined by MTT assay. In addition, TRPM7 gene expression was up-regulated during osteogenesis. These fi ndings demonstrate that TRPM7 is required for MSC survival and perhaps involved in the differentiation process. Introduction Stem cell therapy offers a promising approach to providing an advanced and reliable therapeutic strategy for tissue repair. Mesenchymal stem cells (MSCs) from bone marrow are a source of stem cells capable of differentiation into specialized tissue, including bone, fat, and muscle [ 1 ]. The process of stem cell growth and differentiation is controlled by a network of intracellular signaling molecules that are activated by hormone, growth factor, and/or cytokine stimulation. These signals control gene transcription and the differentiation process [ 2 , 3 ]. Despite a number of studies demonstrating the capability of MSCs to differentiate, the precise mechanism controlling the fate of stem cells is not well understood. Among second messengers, Ca 2+ ions are one of the most important and commonly used molecules for cellular function [ 4 ]. Calcium is available to the cell from 2 sources: fi rst, the extracellular environment, where the Ca 2+ concentration is in the low millimolar range. This Ca 2+ is available to the cytosol through plasma membrane ion channels. Second, there are fi nite intracellular Ca 2+ stores, typically membrane-delineated compartments, such as endoplasmic reticulum (ER), Golgi apparatus, mitochondria, and nucleus. This Ca 2+ is available to the cytosol to differing degrees and exits the storage compartment through intracellular Ca 2+ "release" channels. Increases in intracellular Ca 2+ concentration are a phenomenon commonly observed during stem cell differentiation and linked to the activation of transcriptional programs [ 5 , 6 ]. In MSCs, Ca 2+ oscillations are dependent on both Ca 2+ release from the ER and entry from the extracellular space [ 7 , 8 ]. These signals can be initiated by autocrine or paracrine m...

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels

“…This gene is ubiquitously expressed and is greatest in heart, pituitary gland, bone, and adipose tissue (70,83). In the bone TRPM7 may be regulating extracellular calcium and magnesium, responding to ischemic reperfusion, or regulating osteogenesis (20,57,70). TRPM7 is also abundant in WAT, but the level of expression in bone marrow greatly exceeds that seen in adipocytes, so this is not likely due to the increase in adipocytes alone (35).…”

Inhibition of transient receptor potential melastain 7 channel increases HSCs apoptosis induced by TRAIL

“…As a kind of nonselective cation channels, TRPM7 channels are mostly permeable to divalent cations, such as Ca 2+ , Mg 2+ (Sahmoun and Singh, 2010;Monteilh-Zoller et al, 2003;Schmitz et al, 2003). It constitutively expresses on heart, liver, kidney, lung, brain and other organs and tissues of mammals, participates in many important physical processes such as cell proliferation (Abed and Moreau, 2007;Jiang et al, 2007), survival (Cheng et al, 2010;Wykes et al, 2007) (Clark et al, 2008;Tsavaler et al, 2001), adhesion (Clark et al, 2006;Su et al, 2006), embryonic development (Jin et al, 2012), regulating of Ca 2+ homeostasis (Holoch and Griffith, 2009), and the release of neurotransmitters (Oancea et al, 2006) of the cells. Ion channels are also concerned with several diseases in addition to these life supporting-activities.…”

The channel kinase, TRPM7 , is required for early embryonic development

“…It has been reported that TRPM7 is also required for maintenance of bone marrow-derived mesenchymal stem cells (24). The question is why TRPM7 is dispensable for survival of most terminally differentiated cells types and some multipotent stem cells, such as NP cells, but is required for pluripotent stem cells and some multipotent stem cells, such as mesenchymal stem cells.…”