Intestine is a vital organ for systemic metabolism. In mammals, the intestine is primarily divided into the small intestine and large intestine. The small intestine includes the duodenum, jejunum, and ileum, serves as the main site for nutrient absorption. Its inner wall has abundant villi and microvilli to increase surface area, promoting the breakdown of food by digestive enzymes and absorption. The large intestine includes the cecum, colon, and rectum, primarily handles water reabsorption and feces formation. It also contains a large number of microorganisms, participating in vitamin synthesis and the fermentation of cellulose. Intestinal epithelial cells, immune cells, and endocrine cells work together to ensure digestive function and protect the body from pathogen invasion.
The intestinal structures of mice and humans
(Thi Loan Anh Nguyen, et al., Disease Models &Mechanisms, 2015)
Intestinal-related diseases are numerous in variety, involving multiple aspects ranging from simple digestive discomfort to complex malignant tumors. Common intestinal diseases include inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). IBD is an idiopathic inflammatory disorder of the intestine, encompassing Crohn's Disease (CD) and Ulcerative Colitis (UC). It is characterized by chronic intestinal inflammation leading to various digestive symptoms and is associated with intestinal barrier dysfunction.
IBS is a functional intestinal disorder, triggered by multiple factors leading to abnormal gut-brain interaction. Intestinal microorganisms also receive significant attention as one of the intestinal research hotspots. Many existing literatures indicate that the diversity of intestinal microorganisms is closely related to intestinal homeostasis and host health, capable of influencing the host's metabolic, immune, and nervous systems.
Intestinal Barrier
(Lester Thoo, et al., Cell Death & Disease, 2019)
Gut-Brain Axis Schematic Diagram
(Hetender Singh et al., Journal of Functional Foods,2024)
Recombinant adeno-associated virus vectors (rAAV) possess advantages such as diverse serotypes, low immunogenicity, long-term stable gene expression, and broad host range, occupying a dominant position in gene function research and gene therapy delivery vectors. Based on the limitations of transgenic animals, utilizing AAV vectors to efficiently infect the intestine to study gene function is becoming the choice of more and more researchers.
Selection of AAV Serotype
AAV serotypes are diverse in variety, due to the different capsid protein structures of AAV, they possess different tissue tropisms. AAV9, AAV8, and AAVrh10 serotypes have been reported to be usable for infecting the small intestine and colon. Among them, the AAV9 serotype is the most widely used in intestinal-related research, and is compatible with multiple injection methods.
Infection of Small Intestine and Colon by Different AAV Serotypes via SMA Injection in Mice
(Steven Polyak, et al., Am J Physiol Gastrointest Liver Physiol., 2012)
OBiO Tech provides viral packaging services for over 100 AAV serotypes, including AAV9, AAV8, and AAVrh10.
Selection of Promoters
The promoters most commonly used with AAV targeting the intestine are broad-spectrum promoters such as CBh, CMV, and CAG. Because the intestine is a complex organ, containing a rich diversity of cell types, such as intestinal epithelial cells, goblet cells, intestinal stem cells, endocrine cells, various immune cells, and neuronal cells, Therefore, it is necessary to employ cell-specific promoters to precisely target different types of intestinal cells. The Villin protein is localized to intestinal microvilli and specifically expressed in intestinal epithelial cells, therefore the Villin promoter is used as an intestinal epithelial cell-specific promoter. MUC2 is a secretory protein produced by intestinal epithelial goblet cells, the MUC2 promoter can also target the intestinal epithelium. Additionally, the Lgr5 promoter can specifically target intestinal stem cells.
OBiO Tech offers constitutive promoters (e.g., CBh, CMV, CAG, EF1α) and intestine-specific promoters (e.g., Villin, MUC2, Lgr5) to facilitate the construction of precise and efficient AAV vectors targeting the intestine.
Injection Methods and Dosage
Beyond conventional intraperitoneal injection and tail vein injection, gene delivery methods targeting the intestine include superior mesenteric artery (SMA) injection, enema administration, and intracolonic injection.
Procedure for Superior Mesenteric Artery (SMA) Injection
(Stacy L Porvasnik, et al., Microsurgery, 2010)
Application Cases
Crohn's disease (CD) is a chronic inflammatory gastrointestinal disease with complex etiology. Stanniocalcin-1 (STC1) is a glycoprotein affecting multiple functions, significantly upregulated during inflammation and stress-responsive. The researchers discovered that STC1 expression is significantly increased in the inflamed colonic mucosa of CD patients and chemically-induced mouse colitis models. They further investigated the role of STC1 in colitis and stress-induced cell death, and experimental findings revealed that overexpression of Stc1 and Parp1 mediated by AAV vectors exacerbates DSS-induced colitis in mice.
Stc1 deficiency alleviates DSS-induced acute colitis in mice
(Liguo Zhu, et al., Advanced Science, 2023)
The disruption of the intestinal epithelial barrier is a key factor in the occurrence and progression of CD. The SPARC protein primarily participates in cell-cell interactions and migration, but its specific role in the intestinal epithelial barrier remains unclear. The researchers discovered that elevated SPARC disrupts intestinal barrier integrity in Crohn's disease by interacting with OTUD4 and activating the MYD88/NF-κB pathway. They used AAV9 viral vectors carrying SPARC shRNA driven by the Villin promoter to down-regulate the expression of SPARC in colon epithelial cells, and the results showed that downregulation of SPARC maintained the integrity of intestinal epithelial cells.
Inhibition of SPARC expression improves intestinal epithelial barrier integrity under inflammatory conditions
(Jiayu Wang, et al., Advanced Science, 2025)
Ulcerative colitis (UC) is a chronic nonspecific colonic inflammation, primarily characterized by pathological mucosal destruction, ulcer formation, colonic shortening, diarrhea, and bloody stools. Existing research indicates that polysaccharides play a significant role in UC treatment. The research team discovered that Pueraria lobata polysaccharide (PPL) can alleviate UC by regulating the PI3K signaling pathway. After transfecting C57BL/6 mice with AAV9 for three weeks to reduce PI3K levels, results showed that PI3K knockdown almost completely abolished the therapeutic effect of PPL, indicating that PPL's efficacy entirely depends on PI3K.
Transfection Efficiency and Silencing Efficiency of AAV9-PI3K shRNA
(Zhuang Zhang, et al., Journal of Functional Foods, 2023)
All AAV products in the aforementioned cases were provided exclusively by OBiO Tech. OBiO advances intestinal metabolism research through concrete actions!
References:
[1] Dis Model Mech. 2015 Jan;8(1):1–16. doi: 10.1242/dmm.017400.
[2] Cell Death Dis. 2019 Nov;10(11):849. doi: 10.1038/s41419-019-2086-z.
[3] Journal of Functional Foods. 2024 Jan;112. doi: 10.1016/j.jff.2023.105915.
[4] Am J Physiol Gastrointest Liver Physiol. 2012 Feb 1;302(3):G296-308. doi: 10.1152/ajpgi.00562.2010.
[5] Canadian Journal of Animal Science. 2014 June;94(2):287-293. doi: 10.4141/cjas2013-125.
[6] Am J Pathol. 2012 Apr;180(4):1509–1521. doi: 10.1016/j.ajpath.2012.01.006.
[7] Microsurgery. 2010 Sep;30(6):487-93. doi: 10.1002/micr.20767.
[8] Adv Sci (Weinh). 2024 Feb;11(5):e2304123. doi: 10.1002/advs.202304123.
[9] Adv Sci (Weinh). 2025 Mar;12(11):e2409419. doi: 10.1002/advs.202409419.
[10] Journal of Functional Foods. 2023 May;104. doi: 10.1016/j.jff.2023.105514.
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