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BACKGROUND: Non‐nutritive sweeteners (such as sucralose) bind to sweet receptors Tas1r2/Tas1r3 on intestinal endocrine L cells after diets to upregulate blood glucose. However, the mechanism by which sucralose regulates postprandial blood glucose (PBG) has not been clarified to date. We hypothesized that the gut sweet taste receptor was one of the targets for sucralose to regulate PBG. The aim of this study was to examine the effect of sucralose on PBG based on the gut sweet taste receptor signaling pathway and to explore the mechanism. Therefore, we examined PBG, genes, and proteins associated with the gut sweet receptor pathway in sucralose‐exposed mice. RESULTS: The results showed that after 12 weeks of sucralose exposure the PBG of mice increased significantly, and the expression of intestinal sweet taste receptors increased correspondingly. Within the concentration range of this experiment, a significant increase of PBG was observed in mice fed on sucralose with a concentration equal to or higher than 0.33 g L−1. CONCLUSION: Long‐term consumption of sucralose may increase body weight and the risk of elevated PBG, resulting in overexpression of sweetness receptors and glucose transporters. The mechanism of these effects might be the result of non‐nutritive sweeteners binding to sweetness receptors Tas1r2/Tas1r3 in gut endocrine cells and upregulating Slc5a1 and Slc2a2. But we cannot rule out that the rise in PBG is the result of a combination of sweet receptors and gut microbes. Therefore, the effect of gut microbes on PBG needs to be studied further. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The innate immune system is crucial in fighting SARS-CoV-2 infection, which is responsible for coronavirus disease 2019 (COVID-19). Therefore, deepening our understanding of the underlying immune response mechanisms is fundamental for the development of novel therapeutic strategies. The role of extra-oral bitter (TAS2Rs) and sweet (TAS1Rs) taste receptors in immune response regulation has yet to be fully understood. However, a few studies have investigated the association between taste receptor genes and COVID-19 symptom severity, with controversial results. Therefore, this study aims to deepen the relationship between COVID-19 symptom presence/severity and TAS1R and TAS2R38 (TAS2Rs member) genetic variations in a cohort of 196 COVID-19 patients. Statistical analyses detected significant associations between rs307355 of the TAS1R3 gene and the following COVID-19-related symptoms: chest pain and shortness of breath. Specifically, homozygous C/C patients are exposed to an increased risk of manifesting severe forms of chest pain (OR 8.11, 95% CI 2.26–51.99) and shortness of breath (OR 4.83, 95% CI 1.71–17.32) in comparison with T/C carriers. Finally, no significant associations between the TAS2R38 haplotype and the presence/severity of COVID-19 symptoms were detected. This study, taking advantage of a clinically and genetically characterised cohort of COVID-19 patients, revealed TAS1R3 gene involvement in determining COVID-19 symptom severity independently of TAS2R38 activity, thus providing novel insights into the role of TAS1Rs in regulating the immune response to viral infections. [ABSTRACT FROM AUTHOR]

This study aims to investigate whether the trajectory of dental caries in the life course is associated with rs307355 (TAS1R3) and rs35874116 (TAS1R2) and if there is an epistatic association between rs307355 (TAS1R3) and rs35874116 (TAS1R2). A representative sample of all 5,914 births from the 1982 Pelotas birth cohort was prospectively investigated, and the decayed, missing, and filled teeth (DMF-T) components were assessed at ages 15 (n = 888), 24 (n = 720), and 31 (n = 539) y. Group-based trajectory modeling was used to identify groups with similar trajectories of DMF-T components in the life course. Genetic material was collected, and rs307355 (TAS1R3) and rs35874116 (TAS1R2) were genotyped. Ethnicity was evaluated using ADMIXTURE. Generalized multifactor dimensionality reduction software was used to investigate epistatic interactions. Considering rs307355 (TAS1R3) in the additive effect, the genotype TT was associated with the high decayed trajectory group (odds ratio [OR] = 4.52; 95% confidence interval [CI], 1.15–17.74) and the high missing trajectory group (OR = 3.35; 95% CI, 1.09–10.26). In the dominant effect, the genotype CT/TT was associated with the high decayed trajectory group (OR = 1.64; 95% CI, 1.14–2.35). Allele T was associated with an increased odds of 64% (OR = 1.64; 95% CI, 1.20–2.25) for the decayed component and 41% (OR = 1.41; 95% CI, 1.04–1.92) for the missing component. No associations were observed between rs307355 (TAS1R3) and the filled component. rs35874116 (TAS1R2) was not associated with DMF-T components. Positive epistatic interactions were observed involving rs307355 (TAS1R3) and rs35874116 (TAS1R2) with the decayed component (OR = 1.72; 95% CI, 1.04–2.84). Thus, rs307355 (TAS1R3) genotypes and alleles seem positively associated with the trajectory of decayed and missing components in the life course. Epistatic interaction between rs307355 and rs35874116 may increase the decayed caries trajectory. [ABSTRACT FROM AUTHOR]

The innate immune system is crucial in fighting SARS-CoV-2 infection, which is responsible for coronavirus disease 2019 (COVID-19). Therefore, deepening our understanding of the underlying immune response mechanisms is fundamental for the development of novel therapeutic strategies. The role of extra-oral bitter (TAS2Rs) and sweet (TAS1Rs) taste receptors in immune response regulation has yet to be fully understood. However, a few studies have investigated the association between taste receptor genes and COVID-19 symptom severity, with controversial results. Therefore, this study aims to deepen the relationship between COVID-19 symptom presence/severity and TAS1R and TAS2R38 (TAS2Rs member) genetic variations in a cohort of 196 COVID-19 patients. Statistical analyses detected significant associations between rs307355 of the TAS1R3 gene and the following COVID-19-related symptoms: chest pain and shortness of breath. Specifically, homozygous C/C patients are exposed to an increased risk of manifesting severe forms of chest pain (OR 8.11, 95% CI 2.26–51.99) and shortness of breath (OR 4.83, 95% CI 1.71–17.32) in comparison with T/C carriers. Finally, no significant associations between the TAS2R38 haplotype and the presence/severity of COVID-19 symptoms were detected. This study, taking advantage of a clinically and genetically characterised cohort of COVID-19 patients, revealed TAS1R3 gene involvement in determining COVID-19 symptom severity independently of TAS2R38 activity, thus providing novel insights into the role of TAS1Rs in regulating the immune response to viral infections.

We have previously shown that l -glucose, the non-caloric enantiomer of d -glucose, activates the human sweet taste receptor T1R2/T1R3 transiently expressed in HEK293T cells. Here, we show that d - and l -glucose can also activate T1R2 and T1R3 expressed without the counterpart monomer. Serine mutation to alanine in residue 147 in the binding site of T1R3 VFT domain, completely abolishes T1R3S147A activation by either l - or d- glucose, while T1R2/T1R3S147A responds in the same way as T1R2 expressed without its counterpart. We further show that the original T1R2 reference sequence (NM_152232.1) is less sensitive by almost an order of magnitude than the reference sequence at the time this study was performed (NM_152232.4). We find that out of the four differing positions, it is the R317G in the VFT domain of T1R2, that is responsible for this effect in vitro. It is significant for both practical assay sensitivity and because glycine is found in this position in ~20% of the world population. While the effects of the mutations and the partial transfections were similar for d and l enantiomers, their dose–response curves remained distinct, with l -glucose reaching an early plateau. [ABSTRACT FROM AUTHOR]

Background: The TAS1R2 receptor, known for its role in taste perception, has also emerged as a key regulator of muscle physiology. Previous studies have shown that genetic ablation of TAS1R2 in mice enhances muscle fitness mimicking responses to endurance exercise training. However, the translational relevance of these findings to humans remains uncertain., Methods: We explored responses to endurance exercise training in mice and humans with genetic deficiency of TAS1R2. First, we assessed the effects of muscle-specific deletion of TAS1R2 in mice (mKO) or wild type controls (mWT) following 4 weeks of voluntary wheel running (VWR). Next, we investigated the effects of the TAS1R2 -Ile191Val (rs35874116) partial loss-of-function variant on responses to a 6-month diet-induced weight loss with exercise training (WLEX), weight loss alone (WL), or education control (CON) interventions in older individuals with obesity. Participants were retrospectively genotyped for the TAS1R2 -Ile191Val polymorphism and classified as conventional function (Ile/Ile) or partial loss-of-function (Val carriers: Ile/Val and Val/Val). Body composition, cardiorespiratory fitness, and skeletal muscle mitochondrial function were assessed before and after the intervention., Results: In response to VWR, mKO mice demonstrated enhanced running endurance and mitochondrial protein content. Similarly, TAS1R2 Val carriers exhibited distinctive improvements in body composition, including increased muscle mass, along with enhanced cardiorespiratory fitness and mitochondrial function in skeletal muscle following the WLEX intervention compared to Ile/Ile counterparts. Notably, every Val carrier demonstrated substantial responses to exercise training and weight loss, surpassing all Ile/Ile participants in overall performance metrics., Conclusions: Our findings suggest that TAS1R2 partial loss-of-function confers beneficial effects on muscle function and metabolism in humans in response to exercise training, akin to observations in TAS1R2 muscle-deficient mice. Targeting TAS1R2 may help enhancing exercise training adaptations in individuals with compromised exercise tolerance or metabolic disorders, presenting a potential avenue for personalized exercise interventions., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Published by Elsevier Inc.)

Objective: It is known that genetic variations in the mechanism of taste perception play an essential role in food intake. In this study, we investigated the SNP rs35874116 polymorphism in the sweet taste receptor (TAS1R2) gene and nutrient intakes of adults. Methods: The study conducted with 95 volunteers. Food consumption records of participants obtained by 24-h recall method, and analyzed by Computer-Aided Nutrition Software, Nutrition Information Systems 8.1 Package Software (BeBiS). Venous blood samples of the participants were collected to determine genotype distribution, and genotype distributions were determined using the Kompetitive Allele-Specific PCR (KASP) method. Results: The genotype examination of participants revealed that the percentage of individuals with GA, AA, and GG genotypes were 67.3%, 26.3%, and 6.3% respectively. Daily total carbohydrate and sucrose intakes were found as the highest in individuals with GG genotype (145.55±56.69 g and 28.66±26 g, respectively), but without statistical difference. Conclusion: According to our knowledge the study is the first to examine TAS1R2 polymorphism and nutrient intake in the Turkish population. We did not find any difference between TAS1R2 (rs35874116) polymorphism and nutrient intake; however, the study may serve as a preliminary result. Studies with a wider sample may help to enhance our understanding of the TAS1R2 and nutrient intake. [ABSTRACT FROM AUTHOR]

The aim of the study is to analyze the association of different bitter and sweet gene receptor polymorphisms and bitter and sweet food consumption on formation of dental caries in Turkish adult population. This study included 205 adults whose detailed intraoral health examination was completed and decayed, missing, filled teeth (DMFT) index values were recorded. A mini questionnaire was applied to assess the consumption of bitter and sweet food. A venous blood sample from each participant was collected in Ethylenediamine tetraacetic acid (EDTA) tubes. Further, DNA samples were isolated from the blood samples by utilizing a DNA isolation kit, which were stored at +4 °C prior to the analysis. Taste receptor type 2 member 38 (TAS2R38; rs10246939, rs713598, rs1726866), Taste receptor type 1 member 2 (TAS1R2; rs35874116, rs9701796), and Taste receptor type 1 member 3 (TAS1R3; rs307355) gene polymorphisms were detected using real-time polymerase chain reaction (PCR). There was no statistically significant association between the TAS2R38, TAS1R2, and TAS1R3 gene polymorphism and the DMFT index (p>0.05). No significant difference was found between the consumption of bitter and sweet food and the DMFT index (p>0.05). TAS2R38 (rs10246939, rs713598, rs1726866), TAS1R2 (rs35874116, rs9701796), and TAS1R3 (rs307355) gene polymorphism may not be associated with the formation of dental caries in the Turkish adult population. [ABSTRACT FROM AUTHOR]

Objective: Sweet taste receptors (STR) are expressed in the gut and other extra-oral tissues, suggesting that STR-mediated nutrient sensing may contribute to human physiology beyond taste. A common variant (Ile191Val) in the TAS1R2 gene of STR is associated with nutritional and metabolic outcomes independent of changes in taste perception. It is unclear whether this polymorphism directly alters STR function and how it may contribute to metabolic regulation. Methods: We implemented a combination of in vitro biochemical approaches to decipher the effects of TAS1R2 polymorphism on STR function. Then, as proof-of-concept, we assessed its effects on glucose homeostasis in apparently healthy lean participants. Results: The Ile191Val variant causes a partial loss of function of TAS1R2 through reduced receptor availability in the plasma membrane. Val minor allele carriers have reduced glucose excursions during an OGTT, mirroring effects previously seen in mice with genetic loss of function of TAS1R2. These effects were not due to differences in beta-cell function or insulin sensitivity. Conclusions: Our pilot studies on a common TAS1R2 polymorphism suggest that STR sensory function in peripheral tissues, such as the intestine, may contribute to the regulation of metabolic control in humans.

Sweet taste receptors (STR) are expressed in the gut and other extra-oral tissues, suggesting that STR-mediated nutrient sensing may contribute to human physiology beyond taste. A common variant (Ile191Val) in the TAS1R2 gene of STR is associated with nutritional and metabolic outcomes independent of changes in taste perception. It is unclear whether this polymorphism directly alters STR function and how it may contribute to metabolic regulation. We implemented a combination of in vitro biochemical approaches to decipher the effects of TAS1R2 polymorphism on STR function. Then, as proof-of-concept, we assessed its effects on glucose homeostasis in apparently healthy lean participants. The Ile191Val variant causes a partial loss of function of TAS1R2 through reduced receptor availability in the plasma membrane. Val minor allele carriers have reduced glucose excursions during an OGTT, mirroring effects previously seen in mice with genetic loss of function of TAS1R2. These effects were not due to differences in beta-cell function or insulin sensitivity. Our pilot studies on a common TAS1R2 polymorphism suggest that STR sensory function in peripheral tissues, such as the intestine, may contribute to the regulation of metabolic control in humans. • Sweet taste receptors (STR) have functional roles beyond taste perception. • The TAS1R2 gene of STR is highly polymorphic, suggesting nutrient-dependent adaptive roles. • The Ile191Val variant of TAS1R2 gene causes a partial STR loss-of-function. • Val carriers have reduced glucose excursions mirroring TAS1R2-KO mice. [ABSTRACT FROM AUTHOR]