Propargylglycine inhibits hypotaurine/taurine synthesis and elevates cystathionine and homocysteine concentrations in primary mouse hepatocytes

Our investigation showed that hepatocytes isolated from cysteine dioxygenase knockout mice (Cdo1(−/−)) had lower levels of hypotaurine and taurine than Cdo1(+/+) hepatocytes. Interestingly, hypotaurine accumulates in cultured wild-type hepatocytes. dl-propargylglycine (PPG, inhibitor of cystathionine γ-lyase and H(2)S production) dramatically decreased both taurine and hypotaurine levels in wild-type hepatocytes compared to untreated cells. Addition of 2 mM PPG resulted in the decrease of the intracellular taurine levels: from 10.25 ± 5.00 observed in control, to 2.53 ± 0.68 nmol/mg protein (24 h of culture) and from 17.06 ± 9.40 to 2.43 ± 0.26 nmol/mg protein (control vs. PPG; 48 h). Addition of PPG reduced also intracellular hypotaurine levels: from 7.46 ± 3.55 to 0.31 ± 0.12 nmol/mg protein (control vs. PPG; 24 h) and from 4.54 ± 3.20 to 0.42 ± 0.11 nmol/mg protein (control vs. PPG; 48 h). The similar effects of PPG on hypotaurine and taurine levels were observed in culture medium. PPG blocked hypotaurine/taurine synthesis in wild-type hepatocytes, suggesting that it strongly inhibits cysteinesulfinate decarboxylase (pyridoxal 5′-phosphate-dependent enzyme) as well as cystathionine γ-lyase. In the presence of PPG, intracellular and medium cystathionine levels for both wild-type and Cdo1(−/−) cells were increased. Addition of homocysteine or methionine resulted in higher intracellular concentrations of homocysteine, which is a cosubstrate for cystathionine β-synthase (CBS). It seems that PPG increases CBS-mediated desulfhydration by enhancing homocysteine levels in hepatocytes. There were no overall effects of PPG or genotype on intracellular or medium glutathione levels

Possible Role of Hydrogen Sulfide in Insulin Secretion and in Development of Insulin Resistance

H2S has been proposed as physiological important molecule. It is considered as first endogenous gaseous K+ channel opener. K+ ATP channel activity is mainly responsible for insulin secretion. K+ATP channel opening of β cells leads to inhibition of insulin secretion and channels closing leads to secretion. H2S is the gaseous K+ ATP channel opener but it does not have channel specificity. So, H2S may have some effect on insulin secretion. H2S is high in Zuker diabetic fatty rats. That means H2S is high in insulin resistance condition. We tried to find out the role of H2S in insulin secretion and in development of insulin resistance. From the result of our study, H2S have K+ ATP channel opening activity on β cells. H2S does not have any role in the development of insulin resistance. Decrease in insulin level in Zuker diabetic rat and streptozotocin-induced diabetic rat is due to high H2S level

Empirical Data Confirm Autism Symptoms Related to Aluminum and Acetaminophen Exposure

Autism is a condition characterized by impaired cognitive and social skills, associated with compromised immune function. The incidence is alarmingly on the rise, and environmental factors are increasingly suspected to play a role. This paper investigates word frequency patterns in the U.S. CDC Vaccine Adverse Events Reporting System (VAERS) database. Our results provide strong evidence supporting a link between autism and the aluminum in vaccines. A literature review showing toxicity of aluminum in human physiology offers further support. Mentions of autism in VAERS increased steadily at the end of the last century, during a period when mercury was being phased out, while aluminum adjuvant burden was being increased. Using standard log-likelihood ratio techniques, we identify several signs and symptoms that are significantly more prevalent in vaccine reports after 2000, including cellulitis, seizure, depression, fatigue, pain and death, which are also significantly associated with aluminum-containing vaccines. We propose that children with the autism diagnosis are especially vulnerable to toxic metals such as aluminum and mercury due to insufficient serum sulfate and glutathione. A strong correlation between autism and the MMR (Measles, Mumps, Rubella) vaccine is also observed, which may be partially explained via an increased sensitivity to acetaminophen administered to control fever

The First International Mini-Symposium on Methionine Restriction and Lifespan

It has been 20 years since the Orentreich Foundation for the Advancement of Science, under the leadership Dr. Norman Orentreich, first reported that low methionine (Met) ingestion by rats extends lifespan (Orentreich et al., 1993). Since then, several studies have replicated the effects of dietary methionine restricted (MR) in delaying age-related diseases (Richie et al., 1994; Miller et al., 2005; Ables et al., 2012; Sanchez-Roman and Barja, 2013). We report the abstracts from the First International Mini-Symposium on Methionine Restriction and Lifespan held in Tarrytown, NY, September 2013. The goals were (1) to gather researchers with an interest in MR and lifespan, (2) to exchange knowledge, (3) to generate ideas for future investigations, and (4) to strengthen relationships within this community. The presentations highlighted the importance of research on cysteine, growth hormone (GH), and ATF4 in the paradigm of aging. In addition, the effects of dietary restriction or MR in the kidneys, liver, bones, and the adipose tissue were discussed. The symposium also emphasized the value of other species, e.g., the naked mole rat, Brandt's bat, and Drosophila, in aging research. Overall, the symposium consolidated scientists with similar research interests and provided opportunities to conduct future collaborative studies (Figure 3)

1,25‐dihydroxyvitamin D 3 influences cellular homocysteine levels in murine preosteoblastic MC3T3‐E1 cells by direct regulation of cystathionine β‐synthase

High homocysteine (HCY) levels are a risk factor for osteoporotic fracture. Furthermore, bone quality and strength are compromised by elevated HCY owing to its negative impact on collagen maturation. HCY is cleared by cystathionine β‐synthase (CBS), the first enzyme in the transsulfuration pathway. CBS converts HCY to cystathionine, thereby committing it to cysteine synthesis. A microarray experiment on MC3T3‐E1 murine preosteoblasts treated with 1,25‐dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] revealed a cluster of genes including the cbs gene, of which the transcription was rapidly and strongly induced by 1,25(OH) 2 D 3 . Quantitative real‐time PCR and Western blot analysis confirmed higher levels of cbs mRNA and protein after 1,25(OH) 2 D 3 treatment in murine and human cells. Moreover, measurement of CBS enzyme activity and quantitative measurements of HCY, cystathionine, and cysteine concentrations were consistent with elevated transsulfuration activity in 1,25(OH) 2 D 3 ‐treated cells. The importance of a functional vitamin D receptor (VDR) for transcriptional regulation of cbs was shown in primary murine VDR knockout osteoblasts, in which upregulation of cbs in response to 1,25(OH) 2 D 3 was abolished. Chromatin immunoprecipitation on chip and transfection studies revealed a functional vitamin D response element in the second intron of cbs . To further explore the potential clinical relevance of our ex vivo findings, human data from the Longitudinal Aging Study Amsterdam suggested a correlation between vitamin D status [25(OH)D 3 levels] and HCY levels. In conclusion, this study showed that cbs is a primary 1,25(OH) 2 D 3 target gene which renders HCY metabolism responsive to 1,25(OH) 2 D 3 . © 2011 American Society for Bone and Mineral ResearchPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88106/1/493_ftp.pd