Axelrod 2022 Abstract Bioblast

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Christopher Axelrod
Axelrod Christopher L, Heintz EC, Albaugh VL, Kirwan JP (2022) Segmental regulation of intestinal mitochondrial function. Bioblast 2022: BEC Inaugural Conference.

Link: Bioblast 2022: BEC Inaugural Conference

Axelrod Christopher L, Heintz EC, Albaugh VL, Kirwan JP (2022)

Event: Bioblast 2022

The intestinal mucosa (IM) comprises the inner lining of the intestinal tract, largely consisting of enterocytes with smaller sub-populations of enteroendocrine, immune, goblet, and stem cells. Respiration in IM cells supports nutrient absorption, barrier function, production of mucus, antimicrobial molecules, and growth factors, as well as cellular regeneration. Despite this, little is known of the integrated respiratory functions of mitochondria along the gastrointestinal (GI) tract. The purpose of this study was to develop a procedure to analytically determine respiratory flux of IM derived from varying segments of the GI tract.

Whole, intact intestine was harvested from C57BL/6J mice euthanized by CO2. The GI tract was flushed with ice cold saline, segmented by the jejunum, duodenum, and ileum, and fileted to expose IM. IM were collected directly into MiR05 by scraping the brush border membrane vesicles from the tissue, and mitochondria were subsequently prepared using a glass tissue homogenizer. Prior to assay, total protein was determined by BCA assay and uniformly normalized. Mitochondrial function was determined using a SUIT protocol to determine NADH- and succinate-linked oxidative phosphorylation and electron transfer capacity as well as Complex IV activity. The enzymatic activity of citrate synthase was determined on cryopreserved specimens using spectrophotometry.

Respiration across segments was highly coupled and limited predominantly by OXPHOS, not electron transfer. Substrate coupling was similar between duodenum and jejunum, with depressed NADH- and increased succinate-linked flux in the ileum. Respiratory activity was highest in the duodenum and decreased in a stepwise fashion distally along the GI tract. Conversely, citrate synthase activity was highest in the ileum and decreased in a stepwise fashion proximally along the GI tract.

Mitochondria contained within the IM of the GI tract are energetically robust with differential activity and volume based upon proximity of the segment.

Keywords: Gastrointestinal tract, Intestine, Mucosa, Mitochondria, OXPHOS

O2k-Network Lab: US LA Baton Rouge Noland RC


Affiliations

Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA. -Christopher.Axelrod@pbrc.edu

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Labels: MiParea: Respiration, Instruments;methods 


Organism: Mouse  Tissue;cell: Endothelial;epithelial;mesothelial cell  Preparation: Isolated mitochondria 


Coupling state: LEAK, OXPHOS, ET  Pathway: N, S, CIV  HRR: Oxygraph-2k