Rhonda M Brand1, Nabanita Biswas2, Aaron Siegel3, Ashley Myerski3, Jarret Engstrom3, E Jeffrey Metter4, Randall E Brand2, Ross D Cranston2, Ian McGowan5. 1. University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Magee-Womens Research Institute and Foundation, Pittsburgh, PA, USA. Electronic address: rmb91@pitt.edu. 2. University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. 3. Magee-Womens Research Institute and Foundation, Pittsburgh, PA, USA. 4. University of Tennessee Health Science Center, Memphis, TN, USA. 5. University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Magee-Womens Research Institute and Foundation, Pittsburgh, PA, USA.
Abstract
BACKGROUND: There are limited data on the immunological responsiveness of healthy intestinal tissue when it is cultured and stimulated ex vivo. Such an ex vivo model has the potential to be a valuable tool in understanding disease pathogenesis and as a preclinical tool for the assessment of candidate therapeutic agents used to treat inflammatory bowel disease (IBD). AIM: We undertook a comprehensive study to evaluate ex vivo immunological responses of intestinal tissue and isolated mucosal mononuclear cells (MMC) to a broad range of stimuli. METHODS: Colorectal biopsies (explants) were obtained from healthy participants by flexible sigmoidoscopy and were placed either directly into culture or digested to isolate MMC prior to placement in culture. Explants or MMC were treated with polyinosinic:polycytidylic acid (Poly IC), phytohemagglutinin (PHA), lipopolysacccharides from E Coli (LPS), anti-CD3/CD28 antibodies, or IL-1β/TNF-α for 24 h. Supernatants were assayed for 40 inflammatory biomarkers using multiplexed enzyme-linked immunosorbent assay (ELISA). The isolated MMCs were further characterized using twelve color flow cytometry. RESULTS: Explants have greater weight adjusted constitutive expression of inflammatory biomarkers than MMCs. Biomarker responses varied as a function of immunogen and use of intact tissue or isolated cells. PHA applied to intact explants was the most effective agent in inducing biomarker changes. Stimulation induced activated and memory cellular phenotypes in both explants and MMCs. CONCLUSIONS: The breadth and magnitude of responses from intact and enzymatically digested intestinal tissue explants stimulated with exogenous immunogens are complex and vary by tissue form and treatment. Overall, PHA stimulation of intact explants produced the most robust responses in normal human colorectal tissue. This system could potentially serve as a preliminary model of the disease state, suitable for small scale screening of new therapeutic agents prior to using IBD patient derived tissue.
BACKGROUND: There are limited data on the immunological responsiveness of healthy intestinal tissue when it is cultured and stimulated ex vivo. Such an ex vivo model has the potential to be a valuable tool in understanding disease pathogenesis and as a preclinical tool for the assessment of candidate therapeutic agents used to treat inflammatory bowel disease (IBD). AIM: We undertook a comprehensive study to evaluate ex vivo immunological responses of intestinal tissue and isolated mucosal mononuclear cells (MMC) to a broad range of stimuli. METHODS: Colorectal biopsies (explants) were obtained from healthy participants by flexible sigmoidoscopy and were placed either directly into culture or digested to isolate MMC prior to placement in culture. Explants or MMC were treated with polyinosinic:polycytidylic acid (Poly IC), phytohemagglutinin (PHA), lipopolysacccharides from E Coli (LPS), anti-CD3/CD28 antibodies, or IL-1β/TNF-α for 24 h. Supernatants were assayed for 40 inflammatory biomarkers using multiplexed enzyme-linked immunosorbent assay (ELISA). The isolated MMCs were further characterized using twelve color flow cytometry. RESULTS: Explants have greater weight adjusted constitutive expression of inflammatory biomarkers than MMCs. Biomarker responses varied as a function of immunogen and use of intact tissue or isolated cells. PHA applied to intact explants was the most effective agent in inducing biomarker changes. Stimulation induced activated and memory cellular phenotypes in both explants and MMCs. CONCLUSIONS: The breadth and magnitude of responses from intact and enzymatically digested intestinal tissue explants stimulated with exogenous immunogens are complex and vary by tissue form and treatment. Overall, PHA stimulation of intact explants produced the most robust responses in normal human colorectal tissue. This system could potentially serve as a preliminary model of the disease state, suitable for small scale screening of new therapeutic agents prior to using IBD patient derived tissue.
Authors: Rhonda M Brand; Beverley A Moore; Ashley Zyhowski; Aaron Siegel; Shikhar Uttam; E Jeffrey Metter; Jarret Engstrom; Randall E Brand; Nabanita Biswas; David C Whitcomb; David G Binion; Marc Schwartz; Ian McGowan Journal: Am J Physiol Gastrointest Liver Physiol Date: 2020-12-23 Impact factor: 4.052