A non-functional copy of the salmonid sex determining gene (sdY) is responsible for the “apparent” XY females in Chinook salmon, Oncorhynchus tshawytscha

Many salmonids have a male heterogametic (XX/XY) sex determination system, and they are supposed to have a conserved master sex determining gene (sdY), that interacts at the protein level with Foxl2 leading to the blockage of the synergistic induction of Foxl2 and Nr5a1 of the cyp19a1a promoter. However, this hypothesis of a conserved master sex determining role of sdY in salmonids is challenged by a few exceptions, one of them being the presence of naturally occurring “apparent” XY Chinook salmon, Oncorhynchus tshawytscha, females. Here we show that some XY Chinook salmon females have a sdY gene (sdY-N183), with one missense mutation leading to a substitution of a conserved isoleucine to an asparagine (I183N). In contrast, Chinook salmon males have both a non-mutated sdY-I183 gene and the missense mutation sdY-N183 gene. The 3D model of SdY-I183N predicts that the I183N hydrophobic to hydrophilic amino acid change leads to a modification of the SdY β-sandwich structure. Using in vitro cell transfection assays we found that SdY-I183N, like the wildtype SdY, is preferentially localized in the cytoplasm. However, compared to wildtype SdY, SdY-I183N is more prone to degradation, its nuclear translocation by Foxl2 is reduced and SdY-I183N is unable to significantly repress the synergistic Foxl2/Nr5a1 induction of the cyp19a1a promoter. Altogether our results suggest that the sdY-N183 gene of XY Chinook females is non-functional and that SdY-I183N is no longer able to promote testicular differentiation by impairing the synthesis of estrogens in the early differentiating gonads of wild Chinook salmon XY females.

Epimedin B Through Enhancing NLRP3 Inflammasome Activation To Induces Idiosyncratic Hepatotoxicity

Background: The NLRP3 inflammasome plays a crucial role in the pathogenesis of various human diseases, also idiosyncratic drug-induced liver injury (IDILI). Epimedii Folium (EF) is commonly used for treating bone fractures, joint diseases and some chronic illness, but the EF also could induce IDILI. Several studies have confirmed that EF may induce liver injury by upregulating the activity of the NLRP3 inflammasome. However, the major active constituents of EF have not been well-studied. Results: In the present study, we showed that epimedin B, a major active ingredient of EF, induced the development of IDILI by promoting the activation of the NLRP3 inflammasome. Synergistic induction of mitochondrial reactive oxygen species was a crucial contributor to the promoting effect of epimedin B observed on nigericin- or ATP-induced NLRP3 inflammasome activation. Importantly, epimedin B induced liver injury in the LPS-mediated susceptibility mouse model of IDILI，while specifical NLRP3 inhibitor MCC950 pretreatment completely abrogated the Caspase-1 activation and IL-1β secretion then couldn't induce liver injury. Conclusions: Epimedin B specifically facilitated nigericin- or ATP-induced NLRP3 inflammasome activation and the development of IDILI, which is responsible for EF-induced liver injury. These findings suggest that epimedin B is one of the key constituents of liver injury caused by EF，the content of epimedin B in EF may be a risk factor for IDILI, especially in patients with diseases related to nigericin- or ATP-induced NLRP3 inflammasome activation.

SIGNR1 promotes immune dysfunction in systemic candidiasis by modulating neutrophil lifespan via T cell-derived histones and G-CSF

The mechanisms regulating immune dysfunction during sepsis are poorly understood. Here, we show that neutrophil-derived myeloperoxidase delays the onset of immune dysfunction during systemic candidiasis, by controlling microbes captured by splenic marginal zone (MZ) macrophages. In contrast, SIGNR1-mediated microbe capture accelerates MZ colonization and immune dysfunction by triggering T cell death, T celldependent chromatin release and the synergistic induction of G-CSF by histones and fungi. Histones and G-CSF promote the prevalence of immature Ly6Glow neutrophils with defective oxidative burst, by selectively shortening the lifespan of mature neutrophils. Consistently, either T cell deficiency or blocking SIGNR1, G-CSF and histones delayed neutrophil dysfunction. Furthermore, histones and G-CSF in sepsis patient plasma, shortened neutrophil lifespan, induced surface marker changes and correlated with neutrophil mortality markers associated with a poor prognosis. Hence, microbial capture regulates T cell death and alters neutrophil populations post differentiation, by selectively modulating the lifespan of distinct neutrophil populations.

Differential Effects of Combined ATR/WEE1 Inhibition in Cancer Cells

Inhibitors of WEE1 and ATR kinases are considered promising for cancer treatment, either as monotherapy or in combination with chemo- or radiotherapy. Here, we addressed whether simultaneous inhibition of WEE1 and ATR might be advantageous. Effects of the WEE1 inhibitor MK1775 and ATR inhibitor VE822 were investigated in U2OS osteosarcoma cells and in four lung cancer cell lines, H460, A549, H1975, and SW900, with different sensitivities to the WEE1 inhibitor. Despite the differences in cytotoxic effects, the WEE1 inhibitor reduced the inhibitory phosphorylation of CDK, leading to increased CDK activity accompanied by ATR activation in all cell lines. However, combining ATR inhibition with WEE1 inhibition could not fully compensate for cell resistance to the WEE1 inhibitor and reduced cell viability to a variable extent. The decreased cell viability upon the combined treatment correlated with a synergistic induction of DNA damage in S-phase in U2OS cells but not in the lung cancer cells. Moreover, less synergy was found between ATR and WEE1 inhibitors upon co-treatment with radiation, suggesting that single inhibitors may be preferable together with radiotherapy. Altogether, our results support that combining WEE1 and ATR inhibitors may be beneficial for cancer treatment in some cases, but also highlight that the effects vary between cancer cell lines.

A non-functional copy of the salmonid sex determining gene (sdY) is responsible for the "apparent" XY females in Chinook salmon, Oncorhynchus tshawytscha.

Many salmonids have a male heterogametic (XX/XY) sex determination system, and they are supposed to have a conserved master sex determining gene (sdY), that interacts at the protein level with Foxl2 leading to the blockage of the synergistic induction of Foxl2 and Nr5a1 of the cyp19a1a promoter. However, this hypothesis of a conserved master sex determining role of sdY in salmonids is still challenged by a few exceptions, one of them being the presence of some naturally occurring apparent XY Chinook salmon females. Here we show that XY Chinook salmon females have a sdY gene (sdY-N183), which has one missense mutation leading to a substitution of a conserved isoleucine to an asparagine (SdY I183N). In contrast, Chinook salmon males have both a non-mutated sdY-N183 gene and the missense mutation sdY-N183 gene. The 3D model of SdY-N183 predicts that the I183N hydrophobic to hydrophilic amino acid change leads to a local modification of the β-sandwich structure of SdY. Using in vitro cell transfection assays we found that SdY-N183, like SdY-I183, is preferentially localized in the cytoplasm. However, compared to SdY-I183, SdY-N183 is more prone to degradation, its nuclear translocation by Foxl2 is reduced and SdY-N183 is unable to significantly repress the synergistic Foxl2/Nr5a1 induction of the cyp19a1a promoter. Altogether our results suggest that the sdY-N183 gene of XY Chinook females is a non-functional gene and that SdY-N183 is no longer able to promote testicular differentiation by impairing the synthesis of estrogens in the early differentiating gonads of wild Chinook salmon XY females.

ADAR and hnRNPC deficiency synergize in activating endogenous dsRNA-induced type I IFN responses

Cytosolic double-stranded RNA (dsRNA) initiates type I IFN responses. Endogenous retroelements, notably Alu elements, constitute a source of dsRNA. Adenosine-to-inosine (A-to-I) editing by ADAR induces mismatches in dsRNA and prevents recognition by MDA5 and autoinflammation. To identify additional endogenous dsRNA checkpoints, we conducted a candidate screen in THP-1 monocytes and found that hnRNPC and ADAR deficiency resulted in synergistic induction of MDA5-dependent IFN responses. RNA-seq analysis demonstrated dysregulation of Alu-containing introns in hnRNPC-deficient cells via utilization of unmasked cryptic splice sites, including introns containing ADAR-dependent A-to-I editing clusters. These putative MDA5 ligands showed reduced editing in the absence of ADAR, providing a plausible mechanism for the combined effects of hnRNPC and ADAR. This study contributes to our understanding of the control of repetitive element–induced autoinflammation and suggests that patients with hnRNPC-mutated tumors might maximally benefit from ADAR inhibition-based immunotherapy.

New Anti-Leukemic Effect of Carvacrol and Thymol Combination through Synergistic Induction of Different Cell Death Pathways

Acute myeloid leukemia (AML) is a cancer of the myeloid lineage of blood cells, and treatment for AML is lengthy and can be very expensive. Medicinal plants and their bioactive molecules are potential candidates for improving human health. In this work, we studied the effect of Ptychotis verticillata (PV) essential oil and its derivatives, carvacrol and thymol, in AML cell lines. We demonstrated that a combination of carvacrol and thymol induced tumor cell death with low toxicity on normal cells. Mechanistically, we highlighted that different molecular pathways, including apoptosis, oxidative, reticular stress, autophagy, and necrosis, are implicated in this potential synergistic effect. Using quantitative RT-PCR, Western blotting, and apoptosis inhibitors, we showed that cell death induced by the carvacrol and thymol combination is caspase-dependent in the HL60 cell line and caspase-independent in the other cell lines tested. Further investigations should focus on improving the manufacturing of these compounds and understanding their anti-tumoral mechanisms of action. These efforts will lead to an increase in the efficiency of the oncotherapy strategy regarding AML.