Effects of recombinant human intestinal trefoil factor on trinitrobenzene sulphonic acid induced colitis in rats

Impact of Western Diet and Ultra-Processed Food on the Intestinal Mucus Barrier

The intestinal epithelial barrier plays a key role in the absorption of nutrients and water, in the regulation of the interactions between luminal contents and the underlying immune cells, and in the defense against enteric pathogens. Additionally, the intestinal mucus layer provides further protection due to mucin secretion and maturation by goblet cells, thus representing a crucial player in maintaining intestinal homeostasis. However, environmental factors, such as dietary products, can disrupt this equilibrium, leading to the development of inflammatory intestinal disorders. In particular, ultra-processed food, which is broadly present in the Western diet and includes dietary components containing food additives and/or undergoing multiple industrial processes (such as dry heating cooking), was shown to negatively impact intestinal health. In this review, we summarize and discuss current knowledge on the impact of a Western diet and, in particular, ultra-processed food on the mucus barrier and goblet cell function, as well as potential therapeutic approaches to maintain and restore the mucus layer under pathological conditions.

Parasitic helminth infections in humans modulate Trefoil Factor levels in a manner dependent on the species of parasite and age of the host

Helminth infections, including hookworms and Schistosomes, can cause severe disability and death. Infection management and control would benefit from identification of biomarkers for early detection and prognosis. While animal models suggest that Trefoil Factor Family proteins (TFF2 and TFF3) and interleukin-33 (IL-33) -driven type 2 immune responses are critical mediators of tissue repair and worm clearance in the context of hookworm infection, very little is known about how they are modulated in the context of human helminth infection. We measured TFF2, TFF3, and IL-33 levels in serum from patients in Brazil infected with Hookworm and/or Schistosomes, and compared them to endemic and non-endemic controls. TFF2 was specifically elevated by Hookworm infection in females, not Schistosoma or co-infection. This elevation was correlated with age, but not worm burden. TFF3 was elevated by Schistosoma infection and found to be generally higher in females. IL-33 was not significantly altered by infection. To determine if this might apply more broadly to other species or regions, we measured TFFs and cytokine levels (IFNγ, TNFα, IL-33, IL-13, IL-1β, IL-17A, IL-22, and IL-10) in both the serum and urine of Nigerian school children infected with S. haematobium. We found that serum levels of TFF2 and 3 were reduced by infection, likely in an age dependent manner. In the serum, only IL-10 and IL-13 were significantly increased, while in urine IFN-γ, TNF-α, IL-13, IL-1β, IL-22, and IL-10 were significantly increased in by infection. Taken together, these data support a role for TFF proteins in human helminth infection.

Billions of people are infected with parasitic helminths across the globe, especially in resource poor regions. These infections can result in severe developmental delay, disability, and death. Adequate management of helminth infection would benefit from the identification of host biomarkers in easily obtained samples (e.g. serum or urine) that correlate to infection state. Our goal was to determine if specific proteins involved in tissue repair and immune modulation are altered by infection with specific helminth species in Brazil (hookworm and S. mansoni species of blood fluke) or Nigeria (S. haematobium species of blood fluke). One of these proteins, Trefoil Factor 2 (TFF2), was elevated in the serum of hookworm infected women from Brazil, while another, TFF3 is higher in women than men, but also increased by S. mansoni blood fluke infection. In contrast, both TFFs were decreased in the serum of Nigerian children infected by S. haematobium, while many pro-inflammatory cytokines were increased in the urine, where the eggs emerge from host tissue.

Arjunarishta alleviates experimental colitis via suppressing proinflammatory cytokine expression, modulating gut microbiota and enhancing antioxidant effect

Traditional ayurvedic medicine, Arjunarishta (AA) is used to treat several inflammatory conditions including dysentery associated with blood. The formulation is a decoction of Terminalia arjuna (Roxb.) Wight and Arn. (TA), Madhuca indica J.F.Gmel., Vitis vinifera L., Woodfordia fruticosa (L.) Kurz., and Saccharum officinarum L. Terminalia arjuna, a major constituent of this formulation has been recognized for anti-inflammatory effects. This study aimed at evaluating beneficial effects of AA and probable mechanism of action in Trinitrobenzenesulphonicacid (TNBS) induced colitis model. Response to AA treatment was explored through determination of disease activity index (DAI), histological assessment and damage scores, colonic pro-inflammatory cytokine/chemokine expression and estimation of oxidative stress biomarkers. Improvement in gut microbiome and plasma zinc level was also assessed. Study findings directed therapeutic effects of AA treatment in colitis model by attenuating the colitis symptoms such as weight loss, diarrhoea, blood in stool; histological damage; and downregulated expression of pro-inflammatory cytokines/chemokine (TNF-α, IL-1β, IL-6) and MCP-1). Similarly reduced oxidative stress by decreased level of Nitric Oxide (NO), Myeloperoxidase (MPO), Malondialdehyde (MDA) and enhanced level of Catalase (CAT), Superoxide dismutase (SOD) and Reduced Glutathione (GSH) was also witnessed. In addition, an improved beneficial fecal microbiome profile and restored plasma zinc status was revealed compared to the TNBS control group. The present study directs that downregulated pro-inflammatory cytokines/chemokine expression, enhancement of antioxidant effect, increased plasma zinc status and promising role in modulating fecal microbiome might be potential mechanisms for the therapeutic effect of AA treatment against colitis.

Clustering of disulfide-rich peptides provides scaffolds for hit discovery by phage display: application to interleukin-23

BACKGROUND

Disulfide-rich peptides (DRPs) are found throughout nature. They are suitable scaffolds for drug development due to their small cores, whose disulfide bonds impart extraordinary chemical and biological stability. A challenge in developing a DRP therapeutic is to engineer binding to a specific target. This challenge can be overcome by (i) sampling the large sequence space of a given scaffold through a phage display library and by (ii) panning multiple libraries encoding structurally distinct scaffolds. Here, we implement a protocol for defining these diverse scaffolds, based on clustering structurally defined DRPs according to their conformational similarity.

RESULTS

We developed and applied a hierarchical clustering protocol based on DRP structural similarity, followed by two post-processing steps, to classify 806 unique DRP structures into 81 clusters. The 20 most populated clusters comprised 85% of all DRPs. Representative scaffolds were selected from each of these clusters; the representatives were structurally distinct from one another, but similar to other DRPs in their respective clusters. To demonstrate the utility of the clusters, phage libraries were constructed for three of the representative scaffolds and panned against interleukin-23. One library produced a peptide that bound to this target with an IC₅₀ of 3.3 μM.

CONCLUSIONS

Most DRP clusters contained members that were diverse in sequence, host organism, and interacting proteins, indicating that cluster members were functionally diverse despite having similar structure. Only 20 peptide scaffolds accounted for most of the natural DRP structural diversity, providing suitable starting points for seeding phage display experiments. Through selection of the scaffold surface to vary in phage display, libraries can be designed that present sequence diversity in architecturally distinct, biologically relevant combinations of secondary structures. We supported this hypothesis with a proof-of-concept experiment in which three phage libraries were constructed and panned against the IL-23 target, resulting in a single-digit μM hit and suggesting that a collection of libraries based on the full set of 20 scaffolds increases the potential to identify efficiently peptide binders to a protein target in a drug discovery program.

Trefoil Factor-3 (TFF3) Stimulates De Novo Angiogenesis in Mammary Carcinoma both Directly and Indirectly via IL-8/CXCR2

Mammary carcinoma cells produce pro-angiogenic factors to stimulate angiogenesis and tumor growth. Trefoil factor-3 (TFF3) is an oncogene secreted from mammary carcinoma cells and associated with poor prognosis. Herein, we demonstrate that TFF3 produced in mammary carcinoma cells functions as a promoter of tumor angiogenesis. Forced expression of TFF3 in mammary carcinoma cells promoted proliferation, survival, invasion and in vitro tubule formation of human umbilical vein endothelial cells (HUVEC). MCF7-TFF3 cells with forced expression of TFF3 generated tumors with enhanced microvessel density as compared to tumors formed by vector control cells. Depletion of TFF3 in mammary carcinoma cells by siRNA concordantly decreased the angiogenic behavior of HUVEC. Forced expression of TFF3 in mammary carcinoma cells stimulated IL-8 transcription and subsequently enhanced IL-8 expression in both mammary carcinoma cells and HUVEC. Depletion of IL-8 in mammary carcinoma cells with forced expression of TFF3, or antibody inhibition of IL-8, partially abrogated mammary carcinoma cell TFF3-stimulated HUVEC angiogenic behavior in vitro, as did inhibition of the IL-8 receptor, CXCR2. Depletion of STAT3 by siRNA in MCF-7 cells with forced expression of TFF3 partially diminished the angiogenic capability of TFF3 on stimulation of cellular processes of HUVEC. Exogenous recombinant hTFF3 also directly promoted the angiogenic behavior of HUVEC. Hence, TFF3 is a potent angiogenic factor and functions as a promoter of de novo angiogenesis in mammary carcinoma, which may co-coordinate with the growth promoting and metastatic actions of TFF3 in mammary carcinoma to enhance tumor progression.

Kinetic characterization of an intestinal trefoil factor receptor

Objective

To determine whether intestinal epithelial cells have a receptor for intestinal trefoil factor and characterize receptor-ligand binding kinetics.

Methods

Radioligand binding assays were performed to characterize the binding kinetics between [¹²⁵I]-labeled ITF and IEC-6, HT-29, Caco2 and HaCaT cells. The K_d, B_max and other kinetic variables describing the interaction between ITF and its potential receptors were determined.

Results

Radioligand binding assays performed at 4°C showed that the K_d value for the association between [¹²⁵I]-ITF and IEC-6, HT-29, and Caco2 cells were 1.99±0.12×10⁻⁹ M, 3.89±0.42×10⁻⁹ M, and 2.04±0.17×10⁻⁹ M, respectively. B_max values were 1.17±0.04×10¹¹, 3.97±0.29×10¹¹, and 2.03±0.08×10¹¹ sites/cell, respectively. The K_i values for the interaction between IEC-6, HT-29, and Caco2 cells and non-labeled ITF were 20.98±0.57 nM, 36.87±3.35 nM, and 21.38±0.93 nM, respectively, and the IC₅₀ values were 25.21±0.39 nM, 40.68±0.27 nM, and 23.61±0.25 nM, respectively. Radioligand binding kinetic results showed the association rate constants (k₊₁) for IEC-6, HT-29, and Caco2 cells were 0.22±0.04 min⁻¹, 0.29±0.04 min⁻¹, and 0.26±0.05 min⁻¹, respectively, and the dissociation rate constants (k_-1) were 0.06±0.02 min⁻¹, 0.03±0.01 min⁻¹, and 0.04±0.01 min⁻¹, respectively. For the HaCaT cells, the K_d was 4.86±0.28×10⁻⁸ M and B_max was 5.81±0.15×10⁸ sites/cell, the very low specific binding between [¹²⁵I]-ITF and these cells made it impossible to calculate binding kinetic parameters.

Conclusions

An ITF-specific receptor appears to be present on the three types of intestinal epithelial cells (IEC-6, HT-29, and Caco-2), and there may be no ITF receptor on epidermal cells.

Hapten may play an important role in food allergen-related intestinal immune inflammation

There has been a significant increase in the prevalence of allergic diseases especially over the past 2 to 3 decades. However, the etiology and pathogenesis of food allergy are not fully understood. In recent years, with the huge increase in atopic disease, there has also been an increase in dietary hapten exposure. Allergic reactions to chemical haptens occur, in the overwhelming majority of cases, as an inflammatory reaction in the skin to direct contact with haptens. While reactions to haptens on other epithelial surfaces have only rarely been investigated; it is still not clear whether haptens can combine the food antigens and play a role in the induction of food allergen-related inflammation in the intestine. Further research is needed to reveal the underlying mechanism.