Excessive EFHD1-dependent ER-mitochondrial contacts drive a maladaptive antiviral response in metabolic liver disease
David R. Eberhardt, Emma C. Rekate, Yasmin B. Masini, Hannah E. Duron, David Mollinedo, Adrian M. Velarde, Devorah Stucki, Tara R. Price, Sandra H.J. Lee, Enrique Balderas, Neeraj K. Rai, Ashley R. Bratt, Anthony M. Balynas, Chris J. Stubben, Ryan Bia, Sudipa Maity, Nicolas Hartel, Xue Yin, Andrea Corbin, Anshu Kumari, Dung M. Nguyen, Daisuke Shimura, Vu D. Nguyen, Vishaka Vinod, Kamrul H. Chowdhury, Francisco Verdeguer, Joel Zvick, Patrice N. Mimche, Sihem Boudina, Stavros G. Drakos, Ademuyiwa S. Aromolaran, Sarah Franklin, Vivek Garg, Robin M. Shaw, William L. Holland, Scott A. Summers, Marcus G. Pezzolesi, Jared Rutter, Kimberley J. Evason, Dipayan Chaudhuri
David R. Eberhardt, Emma C. Rekate, Yasmin B. Masini, Hannah E. Duron, David Mollinedo, Adrian M. Velarde, Devorah Stucki, Tara R. Price, Sandra H.J. Lee, Enrique Balderas, Neeraj K. Rai, Ashley R. Bratt, Anthony M. Balynas, Chris J. Stubben, Ryan Bia, Sudipa Maity, Nicolas Hartel, Xue Yin, Andrea Corbin, Anshu Kumari, Dung M. Nguyen, Daisuke Shimura, Vu D. Nguyen, Vishaka Vinod, Kamrul H. Chowdhury, Francisco Verdeguer, Joel Zvick, Patrice N. Mimche, Sihem Boudina, Stavros G. Drakos, Ademuyiwa S. Aromolaran, Sarah Franklin, Vivek Garg, Robin M. Shaw, William L. Holland, Scott A. Summers, Marcus G. Pezzolesi, Jared Rutter, Kimberley J. Evason, Dipayan Chaudhuri
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Research Article Cell biology Hepatology Metabolism

Excessive EFHD1-dependent ER-mitochondrial contacts drive a maladaptive antiviral response in metabolic liver disease

Abstract

Metabolic dysfunction–associated steatohepatitis (MASH) involves hepatocyte damage that cannot be explained solely by lipid accumulation. Here, to discover injury-specific pathways, we focused on a gene of uncertain function, EF-hand domain family member D1 (EFHD1), identified in human genome-wide association studies of liver injury but not liver fat. We showed that EFHD1, a Ca2+-dependent actin cross-linker, stabilizes endoplasmic reticulum–mitochondria contact sites (ERMCS) by detecting spatiotemporal coincidence of interorganellar proximity and ER Ca2+ release. During MASH, EFHD1 upregulation drives pathological mitochondrial fragmentation via excessive contact persistence. This structural failure promotes mitochondrial double-stranded RNA escape and activation of a maladaptive, antiviral, protein kinase RNA-activated–associated stress response, a causal relationship also supported by Mendelian randomization in humans. Consequently, inhibiting EFHD1 in human and mouse models blunts hepatocyte damage. These findings identify EFHD1 as a Ca2+-dependent ERMCS stabilizer, reveal a hepatocyte-intrinsic injury pathway, and suggest EFHD1 inhibition as a therapeutic strategy.

Authors

David R. Eberhardt, Emma C. Rekate, Yasmin B. Masini, Hannah E. Duron, David Mollinedo, Adrian M. Velarde, Devorah Stucki, Tara R. Price, Sandra H.J. Lee, Enrique Balderas, Neeraj K. Rai, Ashley R. Bratt, Anthony M. Balynas, Chris J. Stubben, Ryan Bia, Sudipa Maity, Nicolas Hartel, Xue Yin, Andrea Corbin, Anshu Kumari, Dung M. Nguyen, Daisuke Shimura, Vu D. Nguyen, Vishaka Vinod, Kamrul H. Chowdhury, Francisco Verdeguer, Joel Zvick, Patrice N. Mimche, Sihem Boudina, Stavros G. Drakos, Ademuyiwa S. Aromolaran, Sarah Franklin, Vivek Garg, Robin M. Shaw, William L. Holland, Scott A. Summers, Marcus G. Pezzolesi, Jared Rutter, Kimberley J. Evason, Dipayan Chaudhuri

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Figure 2

EFHD1 is necessary for Ca2+-induced mitochondrial remodeling.

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EFHD1 is necessary for Ca2+-induced mitochondrial remodeling. (A) Repres...
(A) Representative hepatocytes, 200 nM MitoTracker Orange staining before (control) or 5 minutes after treatment with 1 mM ATP (+ATP). Right, boxed insets at higher magnification. (B) Automated iLastik analysis, hepatocyte mitochondrial size. Data are displayed as a bar chart (top) to show mean effects and as a violin plot (bottom) to show the full distribution. Dots in bar chart represent the average value within each cell. (C) Hepatocyte mitochondrial size after 28 weeks of MASH diet, with data displayed as in B. (D) Representative TEM of mouse livers. (E and F) Hepatocyte mitochondrial length from TEM. (G) As in A, but for WT or EFHD1–/– HepG2 cells. (H) As in B, but for HepG2 cells. (I) Mean mitochondrial size. WT and EFHD1–/– are same as in H, ctrl condition. (J and K) Fission events counted after vehicle (PBS, ctrl) or 1 mM ATP. Hepatocytes: MitoTracker label; HepG2: mito-mGold2s label. (L and M) Representative images (L) and summary of mitochondrial length (M). Top, boxed insets in L at higher magnification. Linear mixed effects model: B, C, H, and I, t test: E, F, and M. One-way ANOVA: J and K. N values, figure panel in parentheses. WT: 3,755 mitochondria(m) from 12 cells(c) from 4 animals(a) (B), 1226m 36 c(H); WT+ATP: 2,221m 9c 4a(B), 1,301m 27c(H); EFHD1-KO: 2,306m 10c 6a(B), 927m 25c(H); EFHD1-KO+ATP: 2,286m 10c 5a(B), 1,068m 27c(H). WT: 7,071m 19c 3a(C), 347(E), 274(F); EFHD1-KO: 4,642m 13c 3a(C), 273(E), 294(F). WT: 1,226m 36c(I); EFHD1–/– KO: 927m 25c(I); rescue: 530m 41c(I). WT: 15c(J); WT+ATP: 9(J); Efhd1–/–: 19(J); Efhd1–/–+ATP: 12(J). EFHD1-HA: 22 cells(K); EFHD1-HA+ATP: 29(K); EFHD1–/–: 19(K); EFHD1–/–+ATP: 21(K). WT: 14(M); Efhd1–/–: 9(M). Bars: mean ± SEM.