Search bioRxiv⌕ Search

Biology subjects

Leclercq, I.

Publications and source records attributed to Leclercq, I..

5 recordsLinked to original sources

When the liver is in poor condition, so is the heart - cardiac remodelling in MASH mouse models

Metabolic dysfunction-associated steatohepatitis (MASH) confers a risk for cardiovascular diseases in patients. Animal models may help exploring the mechanisms linking liver and heart diseases. Hence, we explored the cardiac phenotype in MASH mouse models. MethodsWe evaluated pathological alterations in liver and heart in foz/foz mice fed a high fat diet for 24 or 60 weeks and in C57BL/6J mice fed a high fat, high fructose diet for 60 weeks. Angiotensin ll (Angll) was used as an additional cardiovascular stressor. ResultsFoz/foz mice with fibrosing MASH developed cardiac hypertrophy with adverse cardiac remodelling not seen in WT similarly fed the high fat diet. Angll caused hypertension and upregulated the expression of genes contributing to pathological cardiac hypertrophy (Nppa, Myh7) more severely so in foz/foz mice than in controls. After 60 weeks of HFD, while liver disease had progressed to burn-out non steatotic MASH with hepatocellular carcinoma in 50% of the animals, the cardiomyopathy did not. In an independent model (C57BL/6J mice fed a high fat, high fructose diet), moderate fibrosing MASH is associated with cardiac fibrosis and dysregulation of genes involved in pathological remodelling (Collal, Col3al, Vim, Myh6, Slc2al). ConclusionAnimals with MASH present consistent adverse structural changes in the heart with no patent alteration of cardiac function even when stressed with exogenous Angll. Liver disease, and not overfeeding or aging alone, is associated with this cardiac phenotype. Our findings confirm foz/foz mice as suitable for studying links between MASH and heart structural changes ahead of heart failure.

physiology↗

Vascular damage and excessive proliferation compromise liver function after extended hepatectomy in mice

Surgical resection remains the gold standard for liver tumor treatment, yet the emergence of post-operative liver failure, known as the small for size syndrome (SFSS), poses a substantial challenge. The activation of hypoxia sensors in a SFSS liver remnant initiated early angiogenesis, improving vascular architecture, safeguarding against liver failure and reducing mortality. The study aimed to elucidate vascular remodeling mechanisms in SFSS, its impact on hepatocyte function and subsequent liver failure. Mice underwent extended partial hepatectomy to induce SFSS, a subset were exposed to hypoxia immediately after surgery. Hypoxia bolstered post- hepatectomy survival rates. Early proliferation of liver sinusoidal cells coupled with augmented recruitment of endothelial progenitor cells (EPC) via the VEGF/SDF-1 pathway resulted in heightened vascular density, improved lobular perfusion, and limited hemorrhagic events in the regenerating liver under hypoxia. The administration of G-CSF mimicked the effects of hypoxia on vascular remodeling and EPC recruitment, though it failed to rescue survival. Compared to normoxia, hypoxia restrained hepatocyte proliferation yet improved the function of the regenerating remnant, favoring functional preservation in the liver remnant. Injection of AAV8- TBG-HNF4 virus for hepatocyte-specific overexpression of HNF4, the master regulator of hepatocyte function, enforced functionality in proliferating hepatocytes. The combination, only, of HNF4 overexpression and G-CSF treatment rescued survival post-SFSS-setting hepatectomy. In summary, SFSS arises due to imbalance and desynchronized interplay between functional regeneration and vascular restructuring. To enhance survival following SFSS-hepatectomy, a two- pronged strategy is essential, addressing the preservation of function in the proliferating parenchymal cells alongside the simultaneous mitigation of vascular harm. One Sentence SummaryCombined treatment with G-CSF and HNF4 overexpression rescues vascular damage and function to improve survival after extended hepatectomy in mice.

cell biology↗

Heat inactivation of the Monkeypoxvirus

Different kinds of media spiked with Monkeypoxvirus (MPXV) were subjected to heat inactivation at different temperatures, for various periods of time. Our results showed that MPXV was inactivated in less than 5 min at 70 {degrees}C and in less than 15 min at 60 {degrees}C, with no difference between virus from West African and Central African clades. Such indications could help laboratory workers to manipulate the virus in optimal biosafety conditions and improve their protocols.

microbiology↗

Heat inactivation of the Severe Acute Respiratory Syndrome Coronavirus 2

Supernatants of cells infected with SARS-CoV-2, nasopharyngeal and sera samples containing SARS-CoV-2 were submitted to heat inactivation for various periods of time, ranging from 30 seconds to 60 minutes. Our results showed that SARS-CoV-2 could be inactivated in less than 30 minutes, 15 minutes and 3 minutes at 56{degrees}C, 65{degrees}C and 95{degrees}C respectively. These data could help laboratory workers to improve their protocols with handling of the virus in biosafety conditions.

microbiology↗

Influenza A virus environmental persistence is driven by the hemagglutinin and the neuraminidase

The transmission routes of Influenza A viruses (IAVs) submit virus particles to a wide range of environmental conditions that affect their transmission. In water, temperature, salinity and pH are important factors modulating viral persistence in a strain-dependant manner, and the viral factors driving IAV persistence remained to be described. We used an innovative method based on a real-time cell system analysis to quantify viral decay in an environmental model. Thus, we identified the viral hemagglutinin (HA) and neuraminidase (NA) as the main proteins driving the environmental persistence by comparing the inactivation slopes of several reassortant viruses. We also introduced synonymous and non-synonymous mutations in the HA or in the NA that modulated IAV persistence. Our results demonstrate that HA stability and expression level, as well as calcium-binding sites of the NA protein are molecular determinants of viral persistence.\n\nFinally, IAV particles could not trigger membrane fusion after environmental exposure, stressing the importance of the HA and the NA for environmental persistence.

microbiology↗