Tff3 deficiency differentially affects the morphology of male and female intestines in a long-term high-fat-diet-fed mouse model

Šešelja, Kate (author), Bazina, Iva (author), Vrecl, Milka (author), Welss, Jessica (author), Schicht, Martin (author), Paulsen, Friedrich (author), Baus Lončar, Mirela (author), Pirman, Tatjana (author)

Trefoil factor family protein 3 (Tff3) is a small peptide (59 amino acids; 7 kDa) that is a member of the trefoil factor family proteins (Tffs), comprising the Tff1, Tff2, and Tff3 proteins [1]. Tffs share a conserved motif of a well-defined three-loop structure, reminiscent of a trefoil stabilized by three disulfide bonds. Tffs are predominantly expressed in the gastrointestinal tract, where they protect the mucosal surface [2]. The presence of Tff3 in the bloodstream and various other organs, including the liver, brain, pancreas, and lymphoid tissue, indicates its general importance in organisms [3,4]. The mode of action of Tffs ranges from a simple increase in mucous viscosity, cytoprotection, and antiapoptotic and chemotactic effects to more complex immune regulatory functions [5,6]. Tff expression patterns are altered in various tumors, implying a strong association with tumorigenesis [7]. Tffs were long thought to be involved in mucosal repair by promoting cell migration (“restitution”) via their weak chemotactic and anti-apoptotic effects. Recent data on the molecular forms of human Tffs have revealed a more complex situation. Tff1 and Tff3 occur in vivo in different molecular forms and can form disulfide-linked heterodimers. In the intestine, Tff3 occurs as a Tff3-FCGBP (Fc fragment of the IgG binding protein (FCGBP)) heterodimer, Tff3-Tff3 homodimer, and Tff3 monomer [8,9,10,11]. This indicates that the biological functions of Tff peptides are complex [12]. Additionally, minimal amounts of Tff peptides are secreted in an endocrine manner, for example, by the central nervous system (CNS) [12] and immune system [13,14]. The potential role of the Tff3 gene in a metabolism-related condition called diabesity (a combination of diabetes and obesity) was first revealed by quantitative trait locus (QTL) analysis of a mouse model of diabetes, the Tally Ho mouse strain [14], in which the complete reduction of Tff3 in the liver was the most dramatic change in early diabetes. Regulation of Tff3 with appropriate food intake and improvement in glucose tolerance in a diet-induced obesity model raises additional questions regarding the involvement of Tff3 in metabolic pathways [15]. This raises the question of whether Tff3 participates in the gut–liver–brain (GLB) axis. Animal mouse models of Tff protein deficiency are crucial for elucidating the physiological functions of specific proteins. Tff3-deficient mice show markedly increased sensitivity in a dextran sulfate sodium (DSS) colitis model, and these animals are particularly sensitive to radiation-induced mucosal injury and chemotherapy [16,17]. Tff3-deficient mice with a mixed genetic background (sv129/C57BL/6J) exhibit altered liver lipid metabolism [18]. It is well known that the phenotype of a given single gene mutation in mice is modulated by the genetic background of the inbred strain in which the mutation is maintained. This effect is attributable to the modifier genes, which act in combination with the causative gene [19]. A previously existing Tff3-deficient mouse strain had a mixed [18] or C57BL/6J background [16]. C57BL/6J mice have additional genetic variations in the nicotinamide nucleotide transhydrogenase (Nnt) gene, which encodes a mitochondrial redox-induced proton pump that links NADPH synthesis to the mitochondrial metabolic pathway. The Nnt mutation itself modulates metabolism [20,21] and the immune response [22] and hides the physiological function of the investigated candidate protein. The mixed genetic background poses the problem of ensuring a proper wild-type (Wt) control group due to random combinations of genetic variations [23]. Using the Tff3-/-//C57BL/6N mouse model, we overcame the issues of mixed genetic backgrounds and additional mutations in the C57BL/6J strain. Since the Tff3 protein is present in the blood circulation, intestine, liver, and brain, its role in these organs and the pathology of the GLB axis is of great interest. This study aimed to determine the effect of Tff3 deficiency on the intestines of male and female mice under metabolically relevant conditions of long-term consumption of a high-fat diet (HFD) known to have pathological effects on the GLB axis. To exclude the effects of additional mutations and mixed genetic variations, we used a new congenic Tff3-/- strain on the C57BL/6NCrl genetic background with no additional metabolism-relevant mutations [24]. As existing data link Tff3 to metabolism, it is of great interest to investigate the systemic role of Tff3 deficiency in long-term HFD feeding (36 weeks). In this study, we monitored the effects of long-term HFD feeding on intestinal morphology and microbiome-relevant short-chain fatty acid (SCFA) content. The effect of Tff3 deficiency on the expression of genes involved in Tff3 function-related pathways (oxidative and endoplasmic reticulum (ER) stress, apoptosis, and inflammation) was determined using quantitative PCR (qPCR). Since Tff3 is regulated by estrogens [25] and metabolic events are influenced by sex, we monitored the impact of long-term HFD consumption on Wt and Tff3-deficient male and female mice.

• Language: English
• Keywords: trefoil peptide 3, duodenum, cecum, high-fat diet, oxidative stress, ER stress, apoptosis, inflammation
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: VF - Veterinary Faculty; BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: 19 str.
• Numbering: iss. 22, art. 16342
• PID: 20.500.12556/RUL-153447
• UDC: 577
• ISSN on article: 1422-0067
• COBISS.SI-ID: 173255427
• Publication date in RUL: 15.01.2024

Record is a part of a journal

• Title: International journal of molecular sciences
• Shortened title: Int. j. mol. sci.
• Publisher: MDPI
• ISSN: 1422-0067
• COBISS.SI-ID: 2779162

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: biokemija, prebavila, prehrana, visoka vsebnost maščob, laboratorijske podgane, beljakovine, Tff3