TRP channels, omega-3 fatty acids, and oxidative stress in neurodegeneration: from the cell membrane to intracellular cross-links

Transient Receptor Potential-Vanilloid (TRPV1-TRPV4) Channels in the Atlantic Salmon, Salmo salar. A Focus on the Pineal Gland and Melatonin Production

Fish are ectotherm, which rely on the external temperature to regulate their internal body temperature, although some may perform partial endothermy. Together with photoperiod, temperature oscillations, contribute to synchronizing the daily and seasonal variations of fish metabolism, physiology and behavior. Recent studies are shedding light on the mechanisms of temperature sensing and behavioral thermoregulation in fish. In particular, the role of some members of the transient receptor potential channels (TRP) is being gradually unraveled. The present study in the migratory Atlantic salmon, Salmo salar, aims at identifying the tissue distribution and abundance in mRNA corresponding to the TRP of the vanilloid subfamilies, TRPV1 and TRPV4, and at characterizing their putative role in the control of the temperature-dependent modulation of melatonin production-the time-keeping hormone-by the pineal gland. In Salmo salar, TRPV1 and TRPV4 mRNA tissue distribution appeared ubiquitous; mRNA abundance varied as a function of the month investigated. In situ hybridization and immunohistochemistry indicated specific labeling located in the photoreceptor cells of the pineal gland and the retina. Additionally, TRPV analogs modulated the production of melatonin by isolated pineal glands in culture. The TRPV1 agonist induced an inhibitory response at high concentrations, while evoking a bell-shaped response (stimulatory at low, and inhibitory at high, concentrations) when added with an antagonist. The TRPV4 agonist was stimulatory at the highest concentration used. Altogether, the present results agree with the known widespread distribution and role of TRPV1 and TRPV4 channels, and with published data on trout (Oncorhynchus mykiss), leading to suggest these channels mediate the effects of temperature on S. salar pineal melatonin production. We discuss their involvement in controlling the timing of daily and seasonal events in this migratory species, in the context of an increasing warming of water temperatures.

Omega-3 Rich Oils Attenuate ADHD-Like Behaviour Induced by Dietary Monosodium Glutamate in Rats

<b>Background and Objective:</b> Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and cognitive dysfunction. The present study was designed to examine the possible modulatory effect of Fish, Walnuts or Fenugreek Oils against Attention Deficit Hyperactivity Disorder (ADHD)-like Behavior induced by Monosodium Glutamate (MSG) in Rats. <b>Materials and Methods:</b> Fifty weaning rats were divided into five groups, (each group contain 10 rats) as follows: Group 1: Normal control rats were fed on a balanced diet. Groups from 2-5 rats were fed on a balanced diet+MSG (0.4 g kg<sup></sup><sup>1</sup> diet), Group 2 served as a positive control group whereas group 3, 4 and 5 treated with Fish, Walnuts and Fenugreek oil, respectively, (200 mg kg<sup></sup><sup>1</sup> b.wt.) by intra-gastric tube. Biochemical and behavioural parameters were tested as well as microscopic examination of brain tissue was done. <b>Results:</b> MSG ingestion caused marked disruption in locomotors activity, memory function and brain tissue structure along with significant abnormalities in some bio-markers and reduction in the gene expression level of Bcl-2 in brain tissue. However, treatment with the tested oils showed remarkable effect by reversing the condition. <b>Conclusion:</b> Dietary supplementation with walnut; fenugreek or fish oils at the tested dose could modulate the condition of ADHD in rats.

Potential neuroprotective and anti-inflammatory effects provided by omega-3 (DHA) against Zika virus infection in human SH-SY5Y cells

Zika virus (ZIKV) has a strong tropism for the nervous system and has been related to post-infection neurological syndromes. Once neuronal cells are infected, the virus is capable of modulating cell metabolism, leading to neurotoxicity and cellular death. The negative effect of ZIKV in neuron cells has been characterized. However, the description of molecules capable of reversing these cytotoxic effects is still under investigation. In this context, it has been largely demonstrated that docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, is highly neuroprotective. Here, we hypothesized that DHA's neuroprotective proprieties could have an influence on ZIKV-induced neurotoxicity in SH-SY5Y cells. Our data showed that pre-treatment of SH-SY5Y cells with DHA increased the cell viability and proliferation in ZIKV-infected cells. Moreover, DHA triggered an anti-inflammatory response in those infected cells. Besides, DHA was capable of restoring mitochondria function and number in ZIKV-infected SH-SY5Y cells. In addition, cells pre-treated with DHA prior to ZIKV infection presented a lower viral load at different times of infection. Taking together, these results demonstrated that DHA has a potential anti-inflammatory and neuroprotective effect against ZIKV infection in these neuron-like cells and could be a useful tool in the treatment against this virus.

Dietary fatty acid composition impacts plasma fatty acid ethanolamide levels and body composition in golden Syrian hamsters

Fatty acid ethanolamides (FAEs) are a class of lipid amides that regulate numerous pathophysiological functions.

10-oxo-12(Z)-octadecenoic acid, a linoleic acid metabolite produced by gut lactic acid bacteria, enhances energy metabolism by activation of TRPV1

Gut microbiota can regulate the host energy metabolism; however, the underlying mechanisms that could involve gut microbiota-derived compounds remain to be understood. Therefore, in this study, we investigated the effects of KetoA [10-oxo-12(Z)-octadecenoic acid]-a linoleic acid metabolite produced by gut lactic acid bacteria-on whole-body energy metabolism and found that dietary intake of KetoA could enhance energy expenditure in mice, thereby protecting mice from diet-induced obesity. By using Ca²⁺ imaging and whole-cell patch-clamp methods, KetoA was noted to potently activate transient receptor potential vanilloid 1 (TRPV1) and enhance noradrenalin turnover in adipose tissues. In addition, KetoA up-regulated genes that are related to brown adipocyte functions, including uncoupling protein 1 (UCP1) in white adipose tissue (WAT), which was later diminished in the presence of a β-adrenoreceptor blocker. By using obese and diabetic model KK-Ay mice, we further show that KetoA intake ameliorated obesity-associated metabolic disorders. In the absence of any observed KetoA-induced antiobesity effect or UCP1 up-regulation in TRPV1-deficient mice, we prove that the antiobesity effect of KetoA was caused by TRPV1 activation-mediated browning in WAT. KetoA produced in the gut could therefore be involved in the regulation of host energy metabolism.-Kim, M., Furuzono, T., Yamakuni, K., Li, Y., Kim, Y.-I., Takahashi, H., Ohue-Kitano, R., Jheng, H.-F., Takahashi, N., Kano, Y., Yu, R., Kishino, S., Ogawa, J., Uchida, K., Yamazaki, J., Tominaga, M., Kawada, T., Goto, T. 10-oxo-12(Z)-octadecenoic acid, a linoleic acid metabolite produced by gut lactic acid bacteria, enhances energy metabolism by activation of TRPV1.

Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system

Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism.

An efficient and robust fatty acid profiling method for plasma metabolomic studies by gas chromatography-mass spectrometry

BACKGROUND

Targeted metabolomic analysis of fatty acids has linked the dysregulation of fatty acids to many diseases. This study selected five frequently used fatty acid derivatization methods for comparison.

METHODS

We compared the method precisions and derivatization efficiencies, the most economical and best performing method was subjected to method validation. Twenty-four fatty acid standards were used to validate the method, which was later applied to the investigation of potential fatty acid markers of breast cancer.

RESULTS

The acetyl chloride method was demonstrated to provide the best derivatization efficiency and lowest cost for plasma samples. The ionic liquid column successfully separated positional and geometric fatty acid isomers within 26 min under the optimized conditions. Intra-day and inter-day CVs for most of the fatty acids were <10%. Over 90% of the results showed recoveries within 85%-115%. The validated method was applied to investigate potential fatty acid markers of breast cancer. The fatty acid profiling results revealed that 3 fatty acids (C22:0, C24:0, C18:2n6) were significantly lower in both pre- and post-menopausal breast cancer patients (P<0.05).

CONCLUSIONS

We demonstrated that the proposed method is an accurate, efficient and economical method for plasma metabolomic studies of fatty acids.

Development and application of a comparative fatty acid analysis method to investigate voriconazole-induced hepatotoxicity

BACKGROUND

As fatty acids play an important role in biological regulation, the profiling of fatty acid expression has been used to discover various disease markers and to understand disease mechanisms. This study developed an effective and accurate comparative fatty acid analysis method using differential labeling to speed up the metabolic profiling of fatty acids.

METHODS

Fatty acids were derivatized with unlabeled (D0) or deuterated (D3) methanol, followed by GC-MS analysis. The comparative fatty acid analysis method was validated using a series of samples with different ratios of D0/D3-labeled fatty acid standards and with mouse liver extracts.

RESULTS

Using a lipopolysaccharide (LPS)-treated mouse model, we found that the fatty acid profiles after LPS treatment were similar between the conventional single-sample analysis approach and the proposed comparative approach, with a Pearson's correlation coefficient of approximately 0.96. We applied the comparative method to investigate voriconazole-induced hepatotoxicity and revealed the toxicity mechanism as well as the potential of using fatty acids as toxicity markers.

CONCLUSIONS

In conclusion, the comparative fatty acid profiling technique was determined to be fast and accurate and allowed the discovery of potential fatty acid biomarkers in a more economical and efficient manner.

Mechanisms of omega-3 polyunsaturated fatty acids in prostate cancer prevention

This review focuses on several key areas where progress has been made recently to highlight the role of omega-3 polyunsaturated fatty acid in prostate cancer prevention.