Localization of transforming growth factor-beta 1 in mitochondria of murine heart and liver.

Abstract

Using both electron microscopic immunohistochemistry and cell fractionation techniques, we show that transforming growth factor-61 (TGF-,B1) is found in mitochondria of rat and mouse cardiac myocytes and rat hepatocytes. Four different polyclonal antibodies, raised against various epitopes encompassing the mature portion of the TGF-(31 molecule as well as the pro-region of its precursor, were used for the electron microscopy studies. The localization of TGF-,B1 in mitochondria was confirmed by detection of the native peptide in mitochondria isolated from rat heart and liver; the majority of native TGF-,61 found in liver homogenates was recovered in highly pure mitochondrial fractions. The functional role of TGF-(3 in the mitochondrion is unknown at present.

Role of transforming growth factor-beta in maintenance of function of cultured neonatal cardiac myocytes. Autocrine action and reversal of damaging effects of interleukin-1.

“…However, certain cells around the margins ofthe infarct begin staining intensely for TGF-( l 24-48 h after infarction, leading to the suggestion that TGF-(B might accelerate repair and restore function to these myocytes. Recent electron immunohistochemical and parallel cell fractionation studies have shown specific subcellular localization ofTGF-( I in mitochondria and contractile filaments of cardiac myocytes (9). These findings suggest that TGF-(3 has an intrinsic, physiological role in myocytes, which is presently unknown.…”

“…Based on these observations, we postulated that TGF-,B might have an intrinsic role in regulating either cardiac myocyte contractility or energy metabolism (9). Moreover, because ofour interest in defining the roles ofTGF-(3 in acute and chronic cardiac injury, we have examined whether exogenous TGF-# might have direct effects on myocyte function.…”

Reducing mammary cancer risk through premature stem cell senescence

“…The slides were washed in PBS and then exposed to biotinylated, Goat antirabbit gamma-globulin-speci®c antiserum. Positive immunostaining was revealed by an Avidin ± Biotin detection kit (Elite, Vector Laboratories, Inc.) protocol as described previously (Heine et al, 1987). Controls included omission of the primary antibody, and the simultaneous use of MMTV-free negative tissue samples.…”

Expression of transforming growth factor β in the embryonic avian lens coincides with the presence of mitochondria

“…The complete disappearance of mitochondria from individual cells occurred in 2-4 h r and was first observed in E l 2 chicken embryos. Roberts and co-workers (Heine et al, 1991) have reported that TGFPl is located in the mitochondria of rat hepatocytes and myocytes. In the present work, we found that the distribution of TGFp2 and P3 during lens development was similar to that seen previously for mitochondria.…”

“…Recently, TGFp has been detected within the mitochondria of rat hepatocytes and smooth muscle cells (Heine et al, 1991) and in epithelial cells from the ciliary body of the eye (Schlotzer-Schredhardt and Dorfler, 1993). It is technically difficult to co-localize TGFp and mitochondria, requiring the use of cell fractionation or immunocytochemistry at the ultrastructural level.…”