TGF-ß uncouples glycolysis and inflammation in macrophages and controls survival during sepsis.

Changes in metabolism of macrophages are required to sustain macrophage activation in response to different stimuli. We showed that the cytokine TGF-ß (transforming growth factor-ß) regulates glycolysis in macrophages independently of inflammatory cytokine production and affects survival in mouse models of sepsis. During macrophage activation, TGF-ß increased the expression and activity of the glycolytic enzyme PFKL (phosphofructokinase-1 liver type) and promoted glycolysis but suppressed the production of proinflammatory cytokines. The increase in glycolysis was mediated by an mTOR-c-MYC-dependent pathway, whereas the inhibition of cytokine production was due to activation of the transcriptional coactivator SMAD3 and suppression of the activity of the proinflammatory transcription factors AP-1, NF-κB, and STAT1. In mice with LPS-induced endotoxemia and experimentally induced sepsis, the TGF-ß-induced enhancement in macrophage glycolysis led to decreased survival, which was associated with increased blood coagulation. Analysis of septic patient cohorts revealed that the expression of PFKL, TGFBRI (which encodes a TGF-ß receptor), and F13A1 (which encodes a coagulation factor) in myeloid cells positively correlated with COVID-19 disease. Thus, these results suggest that TGF-ß is a critical regulator of macrophage metabolism and could be a therapeutic target in patients with sepsis.

BMPR1A and BMPR1B Missense Mutations Cause Primary Ovarian Insufficiency.

CONTEXT: Primary ovarian insufficiency (POI) is a frequently occurring disorder affecting approximately 1% of women under 40 years of age. POI, which is characterized by the premature depletion of ovarian follicles and elevated plasma levels of follicle-stimulating hormone, leads to infertility. Although various etiological factors have been described, including chromosomal abnormalities and gene mutations, most cases remain idiopathic. OBJECTIVE: To identify and to functionally validate new sequence variants in 2 genes that play a key role in mammalian ovarian function, BMPR1A and BMPR1B (encoding for bone morphogenic protein receptor), leading to POI. METHODS: The impact on bone morphogenic protein (BMP) signaling of BMPR1A and BMPR1B variants, previously identified by whole-exome sequencing on 69 women affected by isolated POI, was established by different in vitro functional experiments. RESULTS: We demonstrate that the BMPR1A-p.Arg442His and BMPR1B-p.Phe272Leu variants are correctly expressed and located but lead to an impairment of downstream BMP signaling. CONCLUSION: In accordance with infertility observed in mice lacking Bmpr1a in the ovaries and in Bmpr1b-/- mice, our results unveil, for the first time, a link between BMPR1A and BMPR1B variants and the origin of POI. We show that BMP signaling impairment through specific BMPR1A and BMPR1B variants is a novel pathophysiological mechanism involved in human POI. We consider that BMPR1A and BMPR1B variants constitute genetic biomarkers of the origin of POI and have clinical utility.

ATG7 and ATG9A loss-of-function variants trigger autophagy impairment and ovarian failure.

PURPOSE: Primary ovarian insufficiency (POI) is a frequent disorder that affects ~1% of women under 40 years of age. POI, which is characterized by the premature depletion of ovarian follicles and elevated plasma levels of follicle-stimulating hormone (FSH), leads to infertility. Although various etiological factors have been described, including chromosomal abnormalities and gene variants, most cases remain idiopathic. The aim of the present study was to identify and validate functionally new sequence variants in ATG (autophagy-related genes) leading to POI. METHODS: We have reanalyzed, in silico, the exome sequencing data from a previously reported work performed in 69 unrelated POI women. Functional experiments using a classical hallmark of autophagy, the microtubule-associated protein 1 light chain 3ß (LC3), were then used to link these genes to this lysosomal degradation pathway. RESULTS: We venture a functional link between ATG7 and ATG9A variants and POI. We demonstrated that variant ATG7 and ATG9A led to a decrease in autophagosome biosynthesis and consequently to an impairment of autophagy, a key biological process implicated in the preservation of the primordial follicles forming the ovarian reserve. CONCLUSION: Our results unveil that impaired autophagy is a novel pathophysiological mechanism involved in human POI.

Functional evidence implicating NOTCH2 missense mutations in primary ovarian insufficiency etiology.

Primary ovarian insufficiency (POI) is a frequently occurring disease affecting women under 40 years old. Recently, we have analyzed unrelated POI women via whole exome sequencing (WES) and identified NOTCH2 mutations underlying possible functional effects. The present study involved reanalyzing of WES assays. We used in the KGN granulosa-like cell model, a synthetic gene reporter construct driving luciferase gene expression to assess the functional effects of five NOTCH2 mutations identified in POI patients. We found that NOTCH2-p.Ser1804Leu, p.Ala2316Val, and p.Pro2359Ala mutations had a functional impact on the protein's transcriptional activity. The results have demonstrated for the first time that NOTCH2 mutations contribute to POI etiology. We therefore recommend sequencing NOTCH2's open reading frame in large panels of POI patients to establish an accurate genotype-phenotype correlation. We cannot rule out the fact that patients affected by Alagille syndrome carrying NOTCH2 mutations may suffer ovarian dysfunction.

A homozygous donor splice-site mutation in the meiotic gene MSH4 causes primary ovarian insufficiency.

Premature ovarian insufficiency (POI) is a frequent pathology that affects women under 40 years of age, characterized by an early cessation of menses and high FSH levels. Despite recent progresses in molecular diagnosis, the etiology of POI remains idiopathic in most cases. Whole-exome sequencing of members of a Colombian family affected by POI allowed us to identify a novel homozygous donor splice-site mutation in the meiotic gene MSH4 (MutS Homolog 4). The variant followed a strict mendelian segregation within the family and was absent in a cohort of 135 women over 50 years of age without history of infertility, from the same geographical region as the affected family. Exon trapping experiments showed that the splice-site mutation induced skipping of exon 17. At the protein level, the mutation p.Ile743_Lys785del is predicted to lead to the ablation of the highly conserved Walker B motif of the ATP-binding domain, thus inactivating MSH4. Our study describes the first MSH4 mutation associated with POI and increases the number of meiotic/DNA repair genes formally implicated as being responsible for this condition.

BMP15 Mutations Associated With Primary Ovarian Insufficiency Reduce Expression, Activity, or Synergy With GDF9.

CONTEXT: Bone morphogenetic protein (BMP)15 is an oocyte-specific growth factor, which, together with growth differentiation factor (GDF) 9, regulates folliculogenesis and ovulation rate. Multiple mutations in BMP15 have been identified in women with primary ovarian insufficiency (POI), supporting a pathogenic role; however, the underlying biological mechanism of many of these mutants remains unresolved. OBJECTIVES: To determine how mutations associated with ovarian dysfunction alter the biological activity of human BMP15. DESIGN: The effects of 10 mutations in BMP15 on protein production, activation of granulosa cells, and synergy with GDF9 were assessed. RESULTS: Sequencing of 35 patients with POI identified both an unrecognized BMP15 variant (c.986G>A, R329H) and a variant (c.581T>C, F194S) previously associated with the condition. Assessing expression and activity of these and 8 other BMP15 mutants identified: (1) multiple variants, including L148P, F194S, and Y235C, with reduced mature protein production; (2) three variants (R138H, A180T, and R329H) with ∼fourfold lower activity than wild-type BMP15; and (3) 3 variants (R68W, F194S, and N196K) with a significantly reduced ability to synergize with GDF9. CONCLUSIONS: Mutations in BMP15 associated with POI reduce mature protein production, activity, or synergy with GDF9. The latter effect is perhaps most interesting given that interactions with GDF9 most likely underlie the physiology of BMP15 in the human ovary.

Plasmodium falciparum rhoptry neck protein 5 peptides bind to human red blood cells and inhibit parasite invasion.

Plasmodium falciparum malaria parasite invasion of erythrocytes is an essential step in host infection and the proteins involved in such invasion are the main target in developing an antimalarial vaccine. Secretory organelle-derived proteins (micronemal AMA1 protein and the RON2, 4, and 5 rhoptry neck proteins) have been recently described as components of moving junction complex formation allowing merozoites to move into a newly created parasitophorous vacuole. This study led to identifying RON5 regions involved in binding to human erythrocytes by using a highly robust, sensitive and specific receptor-ligand interaction assay; it is further shown that the RON5 protein remains highly conserved throughout different parasite strains. It is shown that the binding peptide-erythrocyte interaction is saturable and sensitive to chymotrypsin and trypsin. Invasion inhibition assays using erythrocyte binding peptides showed that the RON5-erythrocyte interaction could be critical for merozoite invasion of erythrocytes. This work provides evidence (for the first time) suggesting a fundamental role for RON5 in erythrocyte invasion.

Binding activity, structure, and immunogenicity of synthetic peptides derived from Plasmodium falciparum CelTOS and TRSP proteins.

Several sporozoite proteins have been associated with Plasmodium falciparum cell traversal and hepatocyte invasion, including the cell-traversal protein for ookinetes and sporozoites (CelTOS), and thrombospondin-related sporozoite protein (TRSP). CelTOS and TRSP amino acid sequences have been finely mapped to identify regions specifically binding to HeLa and HepG2 cells, respectively. Three high-activity binding peptides (HABPs) were found in CelTOS and one HABP was found in TRSP, all of them having high α-helical structure content. These HABPs' specific binding was sensitive to HeLa and HepG2 cells' pre-treatment with heparinase I and chondroitinase ABC. Despite their similarity at three-dimensional (3D) structural level, TRSP and TRAP HABPs located in the TSR domain did not compete for the same binding sites. CelTOS and TRSP HABPs were used as a template for designing modified sequences to then be assessed in the Aotus monkey experimental model. Antibodies directed against these modified HABPs were able to recognize both the native parasite protein by immunofluorescence assay and the recombinant protein (expressed in Escherichia coli) by Western blot and ELISA assays. The results suggested that these modified HABPs could be promising targets in designing a fully effective, antimalarial vaccine.

PvRON2, a new Plasmodium vivax rhoptry neck antigen.

BACKGROUND: Rhoptries are specialized organelles from parasites belonging to the phylum Apicomplexa; they secrete their protein content during invasion of host target cells and are sorted into discrete subcompartments within rhoptry neck or bulb. This distribution is associated with these proteins' role in tight junction (TJ) and parasitophorous vacuole (PV) formation, respectively. METHODS: Plasmodium falciparum RON2 amino acid sequence was used as bait for screening the codifying gene for the homologous protein in the Plasmodium vivax genome. Gene synteny, as well as identity and similarity values, were determined for ron2 and its flanking genes among P. falciparum, P. vivax and other malarial parasite genomes available at PlasmoDB and Sanger Institute databases. Pvron2 gene transcription was determined by RT-PCR of cDNA obtained from the P. vivax VCG-1 strain. Protein expression and localization were assessed by Western blot and immunofluorescence using polyclonal anti-PvRON2 antibodies. Co-localization was confirmed using antibodies directed towards specific microneme and rhoptry neck proteins. RESULTS AND DISCUSSION: The first P. vivax rhoptry neck protein (named here PvRON2) has been identified in this study. PvRON2 is a 2,204 residue-long protein encoded by a single 6,615 bp exon containing a hydrophobic signal sequence towards the amino-terminus, a transmembrane domain towards the carboxy-terminus and two coiled coil α-helical motifs; these are characteristic features of several previously described vaccine candidates against malaria. This protein also contains two tandem repeats within the interspecies variable sequence possibly involved in evading a host's immune system. PvRON2 is expressed in late schizonts and localized in rhoptry necks similar to what has been reported for PfRON2, which suggests its participation during target cell invasion. CONCLUSIONS: The identification and partial characterization of the first P. vivax rhoptry neck protein are described in the present study. This protein is homologous to PfRON2 which has previously been shown to be associated with PfAMA-1, suggesting a similar role for PvRON2.

Identification of the Plasmodium falciparum rhoptry neck protein 5 (PfRON5).

Gathering knowledge about the proteins involved in erythrocyte invasion by Plasmodium merozoites is the starting point for developing new strategies to control malarial disease. Many of these proteins have been studied in Toxoplasma gondii, where some belonging to the Moving Junction complex have been identified. This complex allows a strong interaction between host cell and parasite membranes, required for parasite invasion. In this genus, four rhoptry proteins (RON2, RON4, RON5 and RON8) and one micronemal protein (TgAMA-1) have been found as part of the complex. In Plasmodium falciparum, RON2 and RON4 have been characterized. In the present study, we identify PfRON5, a ~110 kDa protein which is expressed in merozoite and schizont stages of the FCB-2 strain.