Biology subjects

Petitjean, K.

Publications and source records attributed to Petitjean, K..

3 recordsLinked to original sources

bioRxiv2024

The dithiocarbamate pesticides maneb and mancozeb disturb the metabolism of lipids and xenobiotics in an in vitro model of metabolic dysfunction-associated steatotic liver disease

Pesticides are increasingly recognized to be hepatotoxic but less is known about their toxicity in metabolic dysfunction-associated steatotic liver disease (MASLD). Recent investigations reported oxidative stress-induced apoptosis in differentiated hepatocyte-like HepaRG cells after a single treatment with a 7-pesticide mixture that included chlorpyrifos, dimethoate, diazinon, iprodione, imazalil, and the dithiocarbamates maneb and mancozeb. These effects were reproduced by maneb, mancozeb, or manganese chloride (MnCl2). Herein, differentiated HepaRG cells cultured for 2 weeks without (-FA) or with (+FA) a mixture of stearic and oleic acids were treated with this 7-pesticide mixture, maneb, mancozeb, or MnCl2 along the same period. While these molecules did not induce neutral lipid accumulation in -FA-HepaRG cells, they worsened steatosis in +FA-HepaRG cells. Maneb or MnCl2 impaired very low-density lipoprotein (VLDL) secretion and increased fatty acid uptake without altering mitochondrial fatty acid oxidation and de novo lipogenesis. Reduced VLDL secretion was associated with decreased mRNA levels of apolipoproteins B and C3 and microsomal triglyceride transfer protein. Zinc supplementation restored VLDL secretion, reduced fatty acid uptake and prevented the exacerbation of steatosis in +FA-HepaRG cells treated with mancozeb or MnCl2. The mixture, maneb, or MnCl2 also reduced the mRNA expression and activity of several cytochromes P450 in +FA- and -FA-HepaRG cells. This was associated with impaired biotransformation of diazinon while chlorpyrifos metabolism was unaffected. Hence, maneb, mancozeb and MnCl2 disturb the metabolism of lipids and xenobiotics in HepaRG cells, in particular in fatty acid-exposed cells. These findings could have major pathophysiological consequences in dithiocarbamate-exposed individuals with MASLD.

pharmacology and toxicology↗

bioRxiv2023

Low concentrations of ethylene bisdithiocarbamate pesticides maneb and mancozeb impair manganese and zinc homeostasis to induce oxidative stress and caspase-dependent apoptosis in human hepatocytes

The worldwide and intensive use of phytosanitary compounds results in environmental and food contamination by chemical residues. Human exposure to multiple pesticide residues is a major health issue. Considering that the liver is not only the main organ for metabolizing pesticides but also a major target of toxicities induced by xenobiotics, we studied the effects of a mixture of 7 pesticides (chlorpyrifos-ethyl, dimethoate, diazinon, iprodione, imazalil, maneb, mancozeb) often detected in food samples. Effects of the mixture was investigated using metabolically competent HepaRG cells and human hepatocytes in primary culture. We report the strong cytotoxicity of the pesticide mixture towards hepatocytes-like HepaRG cells and human hepatocytes upon acute and chronic exposures at low concentrations extrapolated from the Acceptable Daily Intake (ADI) of each compound. Unexpectedly, we demonstrated that the manganese (Mn)-containing dithiocarbamates (DTCs) maneb and mancozeb were solely responsible for the cytotoxicity induced by the mixture. The mechanism of cell death involved the induction of oxidative stress, which led to cell death by intrinsic apoptosis involving caspases 3 and 9. Importantly, this cytotoxic effect was found only in cells metabolizing these pesticides. Herein, we unveil a novel mechanism of toxicity of the Mn-containing DTCs maneb and mancozeb through their metabolization in hepatocytes generating the main metabolite ethylene thiourea (ETU) and the release of Mn leading to intracellular Mn overload and depletion in zinc (Zn). Alteration of the Mn and Zn homeostasis provokes the oxidative stress and the induction of apoptosis, which can be prevented by Zn supplementation. Our data demonstrate the hepatotoxicity of Mn-containing fungicides at very low doses and unveil their adverse effect in disrupting Mn and Zn homeostasis and triggering oxidative stress in human hepatocytes.

pharmacology and toxicology↗

bioRxiv2020

Long read sequencing and de novo assembly of Hepatitis B Virus identifies 5mCpG in CpG islands

Hepatitis B Virus (HBV) is a 3.2KB DNA virus that causes acute and chronic hepatitis. HBV infection is a world health problem, with 350 million chronically infected people at increased risk of developing liver disease and hepatocellular carcinoma (HCC). Methylation of HBV DNA in a CpG context (5mCpG) can alter the expression patterns of viral genes related to infection and cellular transformation. Moreover, it may also provide clues to why certain infections are cleared, or persist with or without progression to cancer. The detection of 5mCpG often requires techniques that damage DNA or introduce bias through a myriad of limitations. Therefore, we developed a method for the detection of 5mCpG on the HBV genome that does not rely on bisulfite conversion or PCR. With cas9 guided RNPs to specifically target the HBV genome, we enriched in HBV DNA from Primary Human Hepatocytes (PHH) infected with different HBV genotypes, as well as enriching in HBV from infected patient liver tissue; followed by sequencing with Oxford Nanopore Technologies MinION. Detection of 5mCpG by Nanopore sequencing was benchmarked with Bisulfite-quantitative Methyl Specific PCR (BS-qMSP). 5mCpG levels in HBV determined by BS-qMSP and Nanopore sequencing were highly correlated. Our Nanopore sequencing approach achieved a coverage of [~]2000x of HBV depending on infection efficacy, sufficient coverage to perform a de novo assembly and detect small fluctuations in HBV methylation, providing the first de novo assembly of native HBV DNA, as well as the first landscape of 5mCpG from native HBV sequences. Moreover, by capturing entire HBV genomes, we explored the epigenetic heterogeneity of HBV in infected patients and identified 4 epigenetically distinct clusters based on methylation profiles. This method is a novel approach that enables the enrichment of viral DNA in a mixture of nucleic acid material from different species and will serve as a valuable tool for infectious disease monitoring.

genomics↗