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The effects of taurine have been characterized primarily in mammals, and insects are not generally used to study taurine. In this study, ants were used to examine the effect of taurine on eusociality. Ants are the principal models for studying eusociality and superorganisms. Japanese carpenter ants (Camponotus japonicus) were fed a taurine-supplemented diet and tested using ant eusocial indexes. Ant farm structures were constructed using transparent PET bottles containing autoclaved soil. Three categories of vital index were used to study the effect of taurine on group activity: creation of formicaries (residence chambers), cooperative defense efforts, and population density (or group size and composition). Control, low-, and high-taurine diets were prepared using three different levels of taurine in sucrose powder: 0, 5, and 20% (g/g), respectively. The cooperative defense efforts against exogenous queen ants were recorded daily. The high-taurine group took less time to complete their defense formation than the other groups. At least 16% more formicaries (chambers) were observed in the taurine-fed groups than in the control. There were evident differences between control and taurine-fed groups in the total numbers of ants and eggs. The taurine-fed group sustained higher total numbers of ants, excluding the queen. Taurine-fed groups showed a significant increase both in the number of workers and eggs. When fed with taurine, ants responded positively on the eusocial vitality indexes. These results show that taurine exerts a positive effect on the eusociality of ants at the level of the superorganism.

Taurine is traditionally used to treat Down Syndrome (DS); however, the actual foundation for this treatment is not well understood. DS patients suffer from disturbance of the proteostasis network (PN) due to aberrant calcium signaling, which eventually causes endoplasmic reticulum stress (ERS). Taurine has been suggested to play a role in modulating calcium homeostasis and ERS. This study examined whether taurine affects DS symptoms using C. elegans - a DS model in which calcineurins, Ca 2+ /calmodulin-dependent protein phosphatase is mutated to null. The DS nematode model has short body length, slow growth, fertility defects, serotonin-resistant egg-laying defects, and faulty thermal sensing. This study focused on whether taurine may ameliorate the severity of DS at the whole-body level, including reduction in ERS. When treated with taurine, DS nematodes appeared to have lower levels of ERS and phenotypes closer to the wild type. DS nematodes also showed improved egg laying efficiency and thermal sensing index comparable to the wild type. Our findings offer a new perspective on the effectiveness of taurine in treating DS and designing therapeutic strategies to lower ERS and restore disrupted PN.

Down syndrome (DS) patients overexpress human DS critical region gene 1 (hDSCR-1), whose translational product inhibits calcineurin-dependent signaling pathways of genetic transcription. Compared to hDSCR-1, C. elegans rcn-1 has 40% sequence similarity and its proteins share an analogous function with hDSCR-1 in regulating calcineurin. Taurine has had a positive effect on DS patients. According to animal research studies, taurine reduces the expression of MCIP1, a calcineurin inhibitory protein, on C2C12 myotubes and fibroblast in mouse. This study utilizes two C. elegans models for DS: rcn-1 overexpression model, displaying a calcineurin-deficient phenotype, and calcineurin loss-of function mutants. C. elegans larvae were treated with taurine to characterize its effect and mechanism in helping DS patients. RCN-1 expression and behavioral changes were examined in rcn-1 overexpression and calcineurin-deficient models at different concentrations of taurine. When treated with taurine, transgenic worms harboring an rcn-1 reporter (RCN-1::GFP) showed a reduced level of rcn-1 mRNA expression and improved behaviors that were comparable to those in the wild type. These results indicate that taurine exerts a down-regulating effect on the expression of rcn-1 and, consequently, a positive effect on the expression of calcineurins. In summary, taurine may improve the DS symptoms by prompting a positive interaction between RCN-1 and calcineurin. Furthermore, these results suggest that novel mechanisms may regulate interactions among taurine, RCN-1 and calcineurin.

Hair loss or alopecia has been portrayed as a modern malady which is aggravated by stressful conditions. Major cases of alopecia were found among individuals of 40s-50s, nowadays, even among the 20s-30s. This study characterized taurine's potential against alopecia caused by chemical stress agents based on the comparison with other commercially available anti-alopecia agents using Caenorhabditis elegans. The criteria used are their effects on the expression of stress markers and measurements of vital signs: lifespan comparison, progeny number, and mobility. C. elegans showed the typical stress symptoms under treatment with tunicamycin, endoplasmic reticulum stress agent. Hsp-70 protein expression increased, while worm's lifespan and per capita progeny number significantly decreased along with an unusually retarded movement. A positive response was shown when worms were treated with taurine along with astressin-B and finasteride. Between the treatments, finasteride showed better outcomes in terms of stress-reducing effects. Taurine helped worms recover more effectively from adverse influence of stress. In conclusion, there is strong evidence that taurine has a great potential as anti-alopecia effect especially against the one caused by the chemical stress. The present study implies that taurine might strongly work against hair loss when used in combination with other commercially available -anti-alopecia agents.

Background: Taurine plays an important role in reducing physiological stress. Recent studies indicated that taurine may serve as an anti-obesity agent at the cellular level. This study characterizes taurine's potential anti-obesity function in C. elegans, which have become a popular in vivo model for understanding the regulatory basis of lipid biosynthesis and deposition., Methods: Two strains of C. elegans were raised on a normal or high-fat diet: N2 (normal) and RB1600, a mutant in tub-1 that serves as a tubby homologue and functions parallel to the 3-ketoacyl-CoA thiolase gene (kat-1) in regulating lipid accumulation. Taurine's effect on lipid deposition was characterized according to assays of Sudan black B staining, triglyceride content measurement, food consumption, and mobility comparison., Results: When N2 was treated with taurine after the culture in the high-fat media, the worms showed lower lipid accumulation in the assays of the Sudan black B staining and the triglyceride quantification. The anti-obesity effect was less evident in the experiment for RB1600. When the amount of taurine was increased for the high-fat-diet-treated N2 strain, fat deposition decreased and mobility increased in a dose-dependent manner. In the food consumption assays, taurine did not cause a significant change in food intake., Conclusions: Taken together, these results strongly imply that taurine plays an important role in reducing fat deposition by modulating cellular pathways for lipid accumulation and stimulating mobility, but not the pathways for lipid biosynthesis and food intake.

Background: ER stress is a strong indicator of whether or not a cell is undergoing physiological stress. C. elegans is a practical system of characterizing the effect of ER stress at the in vivo or organismal level., Methods: This study characterized taurine's anti-ER stress potential employing western blotting on ER stress markers and assays of motility, lifespan comparison, and fecundity measurement., Results: When treated with tunicamycin, C. elegans showed the typical ER stress symptoms. It showed a higher expression of hsp-70 and skn-1 than the non-treated control. Survivorship significantly decreased under tunicamycin treatment, and the offspring number also decreased. During the synchronized culture under ER stress conditions, the C. elegans showed early signs of aging especially between L3 and L4 within their life span, along with lowered motility. The worms, however, showed a positive response to the taurine treatment under ER stress conditions., Conclusions: When C. elegans were treated with taurine before or after the tunicamycin treatment, they showed a less severe level of ER stress, including an enhanced survivorship, increased motility, and augmented fecundity. Taken together, these results strongly indicate that taurine works positively to cope with ER stress from the organismal perspective.

The present study was undertaken to evaluate effects of dietary taurine supplementation on the homeostasis of trace elements, including Se, Cu, Mn and Cr, in rats chronically consuming alcohol. Male SD rats were fed for 8 wk a liquid form of a control diet (CD), an ethanol diet (ED), or a taurine-supplemented ethanol diet (TED). Plasma Se and Mn concentrations were significantly lower in the ED rats than in the CD rats; dietary taurine supplementation corrected alcohol-induced decreases in plasma Se and Mn levels. Chronic alcohol consumption significantly increased urinary excretion of Se (a 53% increase, p < 0.05), Cr (a 62% increase, p < 0.05), Mn (a 45% increase, p < 0.05) and Cu (a 30% increase, p < 0.05) in rats. Urinary losses of these trace elements induced by chronic alcohol consumption in rats were abolished by taurine supplementation. These results suggest that taurine supplementation in rats may protect against Se, Cr and Mn insufficiency caused by chronic alcohol-mediated loss of the trace elements in the urine.

Cells undergo apoptosis when they are subjected to prolonged ER stress (ERS). Excessive lipid deposition causes ERS in adipocytes; however, it rarely serves as a stress factor that triggers apoptosis. This strongly implies that an anti-ERS mechanism may exist in differentiating adipocytes. We used 3T3L1 (adipocytes) and C2C12 (myocytes) to probe for a potential anti-ERS mechanism. After cells were induced to adipogenesis or myogenesis, they were treated with the ERS inducer, tunicamycin. After tunicamycin-mediated ERS, the expression of the key molecular chaperone, Bip, increased in both cell lines. The chaperone, GRP94, responded differently to extended tunicamycin treatment, with protein levels remaining largely unchanged in 3T3L1 cells but falling in C2C12 cells. In terms of CHOP expression, C2C12 cells contained higher levels than 3T3-L1 cells. When GRP94 expression was reduced by siRNAs, CHOP expression increased. Considering the high levels of GRP94 in 3T3L1 cells under ERS, the small rate of apoptosis in 3T3L1 cells might result from the downregulation of CHOP mediated by GRP94. When C2C12 cells were pretreated with taurine, GRP94 levels appeared to increase and CHOP expression decreased. These results strongly imply that taurine may play an important role in promoting GRP94 expression and blocking the progression to apoptosis under ERS through the inhibition of CHOP upregulation.

The most characterized roles of taurine include osmoregulator and membrane-stabilizing activities. However, much remains to be understood about its role in human physiology concerning its anti-hyperglycemic effect. Studies indicate that taurine-supplemented diet helps alleviate hyperglycemia or insulin resistance. This hypoglycemic effect has been postulated as taurine helping to increase the excretion of cholesterol. Alternatively, this study investigated the effect of taurine on glucose transporter using heterologous expression of sodium-glucose transporter-1 (SGLT-1). SGLT-1 was expressed in Xenopus oocytes and the effect of taurine on the expressed SGLT-1 was analyzed utilizing 2-deoxy-D-glucose (2-DOG) uptake and voltage clamp studies. In the oocytes expressing SGLT-1, taurine was shown to inhibit SGLT-1 activity compared to the non-treated controls in a dose-dependent manner. In the presence of taurine, the glucose uptake was greatly inhibited and the glucose-generated current was significantly inhibited. Synthetic taurine analogs were also shown to be effective in inhibiting SGLT-1 activity in a manner comparable to taurine. These effects might offer a promising opportunity in designing functional foods with anti-hyperglycemic potential by supplementing taurine and its analogs to the diet.