Mitochondrial impairment drives intestinal stem cell transition into dysfunctional Paneth cells predicting Crohn’s disease recurrence

Abstract

ObjectiveReduced Paneth cell (PC) numbers are observed in inflammatory bowel diseases and impaired PC function contributes to the ileal pathogenesis of Crohn’s disease (CD). PCs reside in proximity to Lgr5+ intestinal stem cells (ISC) and mitochondria are critical for ISC-renewal and differentiation. Here, we characterise ISC and PC appearance under inflammatory conditions and describe the role of mitochondrial function for ISC niche-maintenance.DesignIleal tissue samples from patients with CD, mouse models for mitochondrial dysfunction (Hsp60Δ/ΔISC) and CD-like ileitis (TNFΔARE), and intestinal organoids were used to characterise PCs and ISCs in relation to mitochondrial function.ResultsIn patients with CD and TNFΔARE mice, inflammation correlated with reduced numbers of Lysozyme-positive granules in PCs and decreased Lgr5 expression in crypt regions. Disease-associated changes in PC and ISC appearance persisted in non-inflamed tissue regions of patients with CD and predicted the risk of disease recurrence after surgical resection. ISC-specific deletion of Hsp60 and inhibition of mitochondrial respiration linked mitochondrial function to the aberrant PC phenotype. Consistent with reduced stemness in vivo, crypts from inflamed TNFΔARE mice fail to grow into organoids ex vivo. Dichloroacetate-mediated inhibition of glycolysis, forcing cells to shift to mitochondrial respiration, improved ISC niche function and rescued the ability of TNFΔARE mice-derived crypts to form organoids.ConclusionWe provide evidence that inflammation-associated mitochondrial dysfunction in the intestinal epithelium triggers a metabolic imbalance, causing reduced stemness and acquisition of a dysfunctional PC phenotype. Blocking glycolysis might be a novel drug target to antagonise PC dysfunction in the pathogenesis of CD.

Mitochondrial Metabolism in the Intestinal Stem Cell Niche—Sensing and Signaling in Health and Disease

“…Consistently, changes in metabolism as well as mitochondrial genes and proteins have been described in IECs from IBD patients (Mottawea et al, 2016;Rath et al, 2018;Haberman et al, 2019) along with aberrant patterns of LGR5 expression and reduced PC function (Wehkamp et al, 2005;VanDussen et al, 2014;Khaloian et al, 2020). Furthermore, recent data highlight the role of mitochondrial metabolism in deciding on the cellular phenotype and actively determining lineage commitment (Ludikhuize et al, 2019;Khaloian et al, 2020). In line, Paneth cell metaplasia (i.e., occurrence of PCs in the distal colon, where they are physiologically not found) seems to predispose to CRC development (Wada et al, 2005;Pai et al, 2013), and loss of mucin-producing goblet cells is an early event in intestinal inflammation (van der Post et al, 2019;López Cauce et al, 2020).…”

“…For example, shifts in mitochondrial metabolism are well established for cancer cells and are accompanied by ectopic expression of olfactomedin 4 (OLFM4), a marker for actively cycling ISCs that also labels a subset of CRC cells (van der Flier et al, 2009;Ashizawa et al, 2019). Consistently, changes in metabolism as well as mitochondrial genes and proteins have been described in IECs from IBD patients (Mottawea et al, 2016;Rath et al, 2018;Haberman et al, 2019) along with aberrant patterns of LGR5 expression and reduced PC function (Wehkamp et al, 2005;VanDussen et al, 2014;Khaloian et al, 2020). Furthermore, recent data highlight the role of mitochondrial metabolism in deciding on the cellular phenotype and actively determining lineage commitment (Ludikhuize et al, 2019;Khaloian et al, 2020).…”

“…Further dissecting the role of MT-UPR in intestinal stemness, we demonstrated that IEC-specific loss of heat shock protein (Hsp) 60, the major chaperone of the mitochondrial matrix, induced MT-UPR signaling, diminished mitochondrial respiration, and concomitantly abrogated intestinal stemness and proliferation (Berger et al, 2016). Using a model in which Hsp60 deletion was selectively induced in Lgr5 + ISCs, we could furthermore illustrate that Hsp60-deficiency drives Lgr5 + ISC differentiation into a dysfunctional PC phenotype (Khaloian et al, 2020). Of note, in C. elegans, Wnt signaling has been shown to propagate mitochondrial stress across tissues, serving as mitokine to trigger MT-UPR in a cell-non-autonomous fashion (Zhang et al, 2018), indicating a direct link between the major pathway determining intestinal stemness (Wnt) and MT-UPR.…”

“…Yet, lineage-specific ablation of PCs does not result in intestinal inflammation (Durand et al, 2012), and PC dysfunction might be secondary to intestinal inflammation in TNF ARE mice (Schaubeck et al, 2016). Due to dysregulated expression of tumor necrosis factor (Tnf), TNF ARE mice develop a CD-like ileitis that is dependent on microbial composition and characterized by diminished expression of PC-derived AMPs (Schaubeck et al, 2016) and impaired mitochondrial function in the ISC niche (Khaloian et al, 2020). However, aberrances in PC granules are already present in mildly inflamed tissues from TNF ARE mice (Khaloian et al, 2020).…”

Plasticity of Paneth cells and their ability to regulate intestinal stem cells

“…mTORC1, as a nutrient sensor, also controls PC differentiation in the intestinal epithelium; the inactivation of mTORC1 will reduce the function and number of PCs. Prohibitin 1 (PHB1), a mitochondrial membrane component protein, is crucial for maintaining PCs; when loss will lead to defect of PCs, other factors, such as inflammation-associated mitochondrial dysfunction, also produce the same effect [116,117].…”