Supplementary MaterialsSupplementary Information 41467_2020_18753_MOESM1_ESM
July 12, 2021
Supplementary MaterialsSupplementary Information 41467_2020_18753_MOESM1_ESM. of PINCH-1, DRP1 and PYCR1 that regulates mitochondrial dynamics and proline synthesis, and suggest an attractive strategy for alleviation of tumor growth. gene. Consistent with the results from cultured lung adenocarcinoma cells (Figs.?4 and ?and6),6), ablation of PINCH-1 from lung adenocarcinoma significantly increased the protein (Fig.?9a) and mRNA (Fig.?9b) levels of DRP1 and reduced the levels of PYCR1 (Fig.?9a) and proline (Fig.?9c) in vivo. Furthermore, the level of collagen matrix was also significantly reduced (Fig.?9d). Comparable to what we found in culture (Fig.?2), ablation of PINCH-1 significantly reduced cell proliferation (Fig.?10a) in vivo. Importantly, while AKBA expression of KrasG12D markedly induced lung tumor formation in KrasLSL-G12D/+ mice (Fig.?10b), AKBA the tumors formed in KrasLSL-G12D/+; PINCH-1fl/fl mice administrated with Ad-Cre were significantly smaller compared to those in KrasLSL-G12D/+ mice administrated with Ad-Cre (Fig.?10bCe). Consistent with this, ablation of PINCH-1 significantly reduced the mortality rate of the mice with lung adenocarcinoma (Fig.?10f). Open in a separate window Fig. 9 Ablation of AKBA PINCH-1 reduces proline and collagen matrix synthesis in vivo.The lung of the mice was administrated with Ad-Cre and analyzed 16 weeks later. a Sections of the lung tissues from the mice (as specified in the physique) were analyzed by immunostaining with antibodies for PINCH-1 (P1)(top), DRP1 (middle), or PYCR1 (bottom). Bar, 20?m. The boxed areas in the IHC staining were enlarged and shown in the upper right corner. Right panels, the mean intensities of PINCH-1, DRP1, and PYCR1 staining in the KrasLSL?G12D/+; PINCH-1(P1)fl/fl (Kras fl/+; P1fl/fl) group were quantified and compared to those of the Krasfl/+ group (normalized to 1 1; gene transcription. Second, KO of PINCH-1 enhanced mitochondrial fragmentation (Fig.?2eCg), which was reversed by the depletion of DRP1 (Fig.?5bCf), suggesting that PINCH-1 influences mitochondrial fragmentation through regulation of DRP1 expression. Third, in previous studies we have shown that a fraction of kindlin-2 is usually translocated from cytosol to mitochondria where it forms a complex with PYCR1, prevents proteolytic degradation of PYCR1 and thereby promotes proline synthesis11. The cellular mechanism that controls kindlin-2 mitochondrial translocation, complex formation with PYCR1 and consequently proline synthesis, however, was not known. In this study, we show that KO of PINCH-1, which increased DRP1 expression and mitochondrial fragmentation (Figs.?2C4), markedly reduced kindlin-2 mitochondrial translocation, complex formation with PYCR1 and proline Rabbit polyclonal to IL18 synthesis (Fig.?6). Furthermore, depletion DRP1, which reversed mitochondrial fragmentation (Fig.?5bCf), restored kindlin-2 mitochondrial translocation, complex formation with PYCR1 and proline synthesis (Fig.?7bCe). As expected, increase of PYCR1 expression in PINCH-1 KO cells restored proline synthesis (Fig.?8b) and cell proliferation (Fig.?8c, d). Collectively, these findings suggest that PINCH-1 regulates PYCR1 and proline synthesis through, at least in part, control of DRP1 expression and consequently mitochondrial fragmentation, kindlin-2 mitochondrial translocation and complex formation with PYCR1. Consistent with an essential role of kindlin-2 in PINCH-1-mediated regulation of PYCR1 and proline synthesis, overexpression of PINCH-1 was unable to increase the levels of PYCR1 and proline in the absence of kindlin-2 (Supplementary Fig.?6). Interestingly, increase of PYCR1 expression reversed the PINCH-1 deficiency-induced increase of DRP1 expression (Fig.?8a) and AKBA mitochondrial fragmentation (Fig.?8eCg), suggesting that there is a feedback system through which PYCR1 or proline synthesis regulates DRP1 expression and mitochondrial dynamics. In other words, DRP1 and mitochondrial dynamics not only exert a strong influence on PYCR1 and proline synthesis but they themselves are also regulated by PYCR1 or proline synthesis. This feedback system may help cells to respond quickly the need for increase proline synthesis in fasting proliferating cells such as cancer cells. In this regard, it is worth noting that deprivation of cellular nutrition is known to have a strong impact on mitochondrial dynamics14,15,47C50. It will be interesting to determine in future studies whether PYCR1 regulates DRP1 and mitochondrial dynamics directly or indirectly through control of proline synthesis and the specific signaling pathways that are involved. In addition to showing that PINCH-1 regulates proline synthesis, cell proliferation, collagen matrix deposition, and tumor growth and revealing a signaling axis consisting of PINCH and DRP1 that functions in regulation of these processes, the findings presented in this paper suggest that the function of DRP1 in regulation of proline.