Trefoil Factor Family Member 2: From a High-Fat-Induced Gene to a Potential Obesity Therapy Target

IgG Fc-binding protein positively regulates the assembly of pore-forming protein complex βγ-CAT evolved to drive cell vesicular delivery and transport

Cell membranes form barriers for molecule exchange between the cytosol and the extracellular environments. βγ-CAT, a complex of pore-forming protein (PFP) BmALP1 (two βγ-crystallin domains with an aerolysin pore-forming domain) and the trefoil factor BmTFF3, has been identified in toad Bombina maxima. It plays pivotal roles, via inducing channel formation in various intra- or extra- cellular vesicles, as well as in nutrient acquisition, maintaining water balance, and antigen presentation. Thus, such a protein machine should be tightly regulated. Indeed, BmALP3 (a paralog of BmALP1) oxidizes BmALP1 to form a water-soluble polymer, leading to dissociation of the βγ-CAT complex and loss of biological activity. Here, we found that the B. maxima IgG Fc-binding protein (FCGBP), a well-conserved vertebrate mucin-like protein with unknown functions, acted as a positive regulator for βγ-CAT complex assembly. The interactions among FCGBP, BmALP1, and BmTFF3 were revealed by co-immunoprecipitation assays. Interestingly, FCGBP reversed the inhibitory effect of BmALP3 on the βγ-CAT complex. Furthermore, FCGBP reduced BmALP1 polymers and facilitated the assembly of βγ-CAT with the biological pore-forming activity in the presence of BmTFF3. Our findings define the role of FCGBP in mediating the assembly of a PFP machine evolved to drive cell vesicular delivery and transport.

In Vitro Mimicking of Obesity-Induced Biochemical Environment to Study Obesity Impacts on Cells and Tissues

Obesity represents a heavy burden for modern healthcare. The main challenge facing obesity research progress is the unknown underlying pathways, which limits our understanding of the pathogenesis and developing therapies. Obesity induces specific biochemical environments that impact the different cells and tissues. In this piece of writing, we suggest mimicking obesity-induced in vivo biochemical environments including pH, lipids, hormones, cytokines, and glucose within an in vitro environment. The concept is to reproduce such biochemical environments and use them to treat the tissue cultures, explant cultures, and cell cultures of different biological organs. This will allow us to clarify how the obesity-induced biochemistry impacts such biological entities. It would also be important to try different environments, in terms of the compositions and concentrations of the constitutive elements, in order to establish links between the effects (impaired regeneration, cellular inflammation, etc.) and the factors constituting the environment (hormones, cytokines, etc.) as well as to reveal dose-dependent effects. We believe that such approaches will allow us to elucidate obesity mechanisms, optimize animal models, and develop therapies as well as novel tissue engineering applications.

Diet Impact on Obesity beyond Calories and Trefoil Factor Family 2 (TFF2) as an Illustration: Metabolic Implications and Potential Applications

Obesity is a health problem with increasing impacts on public health, economy and even social life. In order to reestablish the energy balance, obesity management focuses mainly on two pillars; exercise and diet. Beyond the contribution to the caloric intake, the diet nutrients and composition govern a variety of properties. This includes the energy balance-independent properties and the indirect metabolic effects. Whereas the energy balance-independent properties are close to "pharmacological" effects and include effects such as antioxidant and anti-inflammatory, the indirect metabolic effects represent the contribution a diet can have on energy metabolism beyond the caloric contribution itself, which include the food intake control and metabolic changes. As an illustration, we also described the metabolic implication and hypothetical pathways of the high-fat diet-induced gene Trefoil Factor Family 2. The properties the diet has can have a variety of applications mainly in pharmacology and nutrition and further explore the "pharmacologically" active food towards potential therapeutic applications.

Trefoil Factor Family Member 2 Expression as an Indicator of the Severity of the High-Fat Diet-Induced Obesity

Trefoil Factor Family Member 2 (TFF2) belongs to TFF family peptides that includes TFF1, TFF2, TFF3. TFF2 is mainly known for its roles in the mucosal protection. In the context of obesity and high fat diet (HFD), Tff2 has been characterized as a HFD-induced gene. The knock-out of Tff2 in mice lead to the protection from HFD-induced obesity with a metabolic profile towards a negative energy balance. Such HFD-specific expression gives Tff2 a pattern worth exploring in biomedical research. Indeed, measuring TFF2/TFF2/Tff2 expression in biological samples following the ingestion of high-fat diet reflects the biological "responsiveness" to the lipids ingestion and would reflect the severity of obesity establishment afterwards. Such property could be explored for instance to screen animal models, evaluate the predisposition to HFD-induced obesity as well as in biomedical and clinical applications. Results might advance obesity research especially in terms of understanding lipid-induced signals, appetite control and adiposity storage.