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Protein kinase N1 critically regulates cerebellar development and longterm function

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Abstract

Increasing evidence suggests that synapse dysfunctions are a major determinant of several neurodevelopmental and neurodegenerative diseases. Here we identify protein kinase N1 (PKN1) as a novel key player in fine-tuning the balance between axonal outgrowth and presynaptic differentiation in the parallel fiber (PF)-forming cerebellar granule cells (Cgc). Postnatal Pkn1–/– animals showed a defective PF-Purkinje cell (PC) synapse formation. In vitro, Pkn1–/– Cgc exhibited deregulated axonal outgrowth, elevated AKT phosphorylation and higher levels of neuronal differentiation-2 (NeuroD2), a transcription factor preventing presynaptic maturation. Concomitantly Pkn1–/– Cgc had a reduced density of presynaptic sites. By inhibiting AKT with MK-2206 and siRNA-mediated knockdown, we found that AKT hyperactivation is responsible for the elongated axons, higher NeuroD2 levels and the reduced density of presynaptic specifications in Pkn1–/– Cgc. In line with our in vitro data, Pkn1–/– mice showed AKT hyperactivation, elevated NeuroD2 levels and reduced expression of PF-PC synaptic markers during stages of PF maturation in vivo. The long-term effect of Pkn1 knockout was further seen in cerebellar atrophy and mild ataxia. In summary, our results demonstrate that PKN1 functions as a developmentally active gatekeeper of AKT activity, thereby fine-tuning axonal outgrowth and presynaptic differentiation of Cgc and subsequently the correct PF-PC synapse formation.

Authors

Stephanie zur Nedden, Rafaela Eith, Christoph Schwarzer, Lucia Zanetti, Hartwig Seitter, Friedrich Fresser, Alexandra Koschak, Angus J.M. Cameron, Peter J. Parker, Gottfried Baier, Gabriele Baier-Bitterlich

Self-adjuvanting nanoemulsion targeting dendritic cell receptor Clec9A enables antigen-specific immunotherapy

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Abstract

Non-antigen-specific stimulatory cancer immunotherapies are commonly complicated by off-target effects. Antigen-specific immunotherapy, combining viral tumor antigen or personalised neo-epitopes with immune targeting, offers a solution. However, the lack of flexible systems targeting tumor antigens to cross-presenting dendritic cells (DCs) limits clinical development. Although antigen-anti-CLEC-9A mAb conjugates target cross-presenting DCs, adjuvant must be co-delivered for cytotoxic T-cell (CTL) induction. We functionalized tailored nanoemulsions encapsulating tumor antigens to target Clec9A (Clec9A-TNE). Clec9A-TNE encapsulating ovalbumin (OVA) antigen targeted and activated cross-presenting DCs without additional adjuvant, promoting antigen-specific CD4+ and CD8+ T cell proliferation, CTL and antibody responses. OVA-Clec9A-TNE-induced DC activation required CD4 and CD8 epitopes, CD40 and IFN-α. Clec9A-TNE encapsulating human papillomavirus (HPV) E6-E7 significantly suppressed HPV-associated tumor growth while E6-E7-CpG did not. Clec9A-TNE loaded with pooled B16F10 melanoma neo-epitopes induced epitope-specific CD4+ and CD8+ T cell responses, permitting selection of immunogenic neo-epitopes. Clec9A-TNE encapsulating six neo-epitopes significantly suppressed B16-F10 melanoma growth in a CD4 T cell-dependent manner. Thus, cross-presenting DCs targeted with antigen-Clec9A-TNE stimulate therapeutically-effective tumor-specific immunity, dependent on T cell help.

Authors

Bijun Zeng, Anton P.J. Middelberg, Adrian Gemiarto, Kelli MacDonald, Alan G. Baxter, Meghna Talekar, Davide Moi, Kirsteen M. Tullett, Irina Caminschi, Mireille H. Lahoud, Roberta Mazzieri, Riccardo Dolcetti, Ranjeny Thomas

Redirection to the bone marrow improves T cell persistence and antitumor functions

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Abstract

A key predictor for the success of gene-modified T cell therapies for cancer is the persistence of transferred cells in the patient. The propensity of less differentiated memory T cells to expand and survive efficiently has therefore made them attractive candidates for clinical application. We hypothesized that re-directing T cells to specialized niches in the bone marrow (BM) that support memory differentiation would confer increased therapeutic efficacy. We show that overexpression of chemokine receptor CXCR4 in CD8+ T cells (TCXCR4) enhanced their migration towards vascular-associated CXCL12+ cells in the BM and increased their local engraftment. Increased access of TCXCR4 to the BM microenvironment induced IL-15-dependent homeostatic expansion and promoted the differentiation of memory precursor-like cells with low expression of programmed death-1, resistance to apoptosis and a heightened capacity to generate poly-functional cytokine-producing effector cells. Following transfer to lymphoma-bearing mice, TCXCR4 showed a greater capacity for effector expansion and better tumor protection, the latter being independent of changes in trafficking to the tumor bed or local out-competition of regulatory T cells. Thus, re-directed homing of T cells to the BM confers increased memory differentiation and anti-tumor immunity, suggesting an innovative solution to increase the persistence and functions of therapeutic T cells.

Authors

Anjum B. Khan, Ben Carpenter, Pedro Santos e Sousa, Constandina Pospori, Reema Khorshed, James Griffin, Pedro Veliça, Mathias Zech, Sara Ghorashian, Calum Forrest, Sharyn Thomas, Sara Gonzalez Anton, Maryam Ahmadi, Angelika Holler, Barry Flutter, Zaida Ramirez-Ortiz, Terry K. Means, Clare L. Bennett, Hans Stauss, Emma Morris, Cristina Lo Celso, Ronjon Chakraverty

Mycobacterial growth inhibition is associated with trained innate immunity

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Abstract

The lack of defined correlates of protection hampers development of vaccines against tuberculosis (TB). In vitro mycobacterial outgrowth assays are thought to better capture the complexity of the human host/Mycobacterium tuberculosis (Mtb) interaction. We used a PBMC-based “mycobacterial-growth-inhibition-assay” (MGIA) to investigate the capacity to control outgrowth of Bacille Calmette-Guérin (BCG). Interestingly, strong control of BCG outgrowth was observed almost exclusively in individuals with recent exposure to Mtb, but not in (long-term) latent TB infection, and only modestly in BCG vaccinees. Mechanistically, control of mycobacterial outgrowth strongly correlated with the presence of a CD14dim monocyte population, but also required the presence of T cells. The nonclassical monocytes produced CXCL10, and CXCR3-receptor blockade inhibited the capacity to control BCG outgrowth. Expression of CXCR3 splice variants was altered in recently Mtb exposed individuals. Cytokines previously associated with trained immunity were detected in MGIA supernatants, and CXCL9, CXCL10, and CXCL11 represent new markers of trained immunity. These data indicate that CXCR3-ligands are associated with trained immunity and critical factors in controlling mycobacterial outgrowth.In conclusion, control of mycobacterial outgrowth early after exposure to Mtb is the result of trained immunity mediated by a CXCL10-producing non-classical CD14dim monocyte subset.

Authors

Simone A. Joosten, Krista E. van Meijgaarden, Sandra M. Arend, Corine Prins, Fredrik Oftung, Gro Ellen Korsvold, Sandra V. Kik, Rob J.W. Arts, Reinout van Crevel, Mihai G. Netea, Tom H.M. Ottenhoff

Mosaic RAS/MAPK variants cause sporadic vascular malformations which respond to targeted therapy

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Abstract

BACKGROUND. Sporadic vascular malformations (VMs) are complex congenital anomalies of blood vessels that lead to stroke, life-threatening bleeds, disfigurement, overgrowth, and/or pain. Therapeutic options are severely limited and multi-disciplinary management remains challenging, particularly for high-flow arteriovenous malformations (AVM). METHODS. To investigate the pathogenesis of sporadic intracranial and extracranial VMs in 160 children in which known genetic causes had been excluded, we sequenced DNA from affected tissue and optimised analysis for detection of low mutant allele frequency. RESULTS. We discovered multiple mosaic activating variants in four genes of the RAS-MAPK pathway, KRAS, NRAS, BRAF, and MAP2K1, a pathway commonly activated in cancer and responsible for the germ-line RAS-opathies. These variants were more frequent in high-flow than low-flow VMs. In vitro characterisation and two transgenic zebrafish AVM models which recapitulated the human phenotype validated the pathogenesis of the mutant alleles. Importantly, treatment of AVM-BRAF mutant zebrafish with the BRAF inihibitor, Vemurafinib, restored blood flow in AVM. CONCLUSIONS. Our findings uncover a major cause of sporadic vascular malformations of different clinical types, and thereby offer the potential of personalised medical treatment by repurposing existing licensed cancer therapies. FUNDING. This work was funded or supported by grants from AVM Butterfly Charity, the Wellcome Trust (UK), the Medical Research Council (UK), the UK National Institute for Health Research, L’Oreal-Melanoma Research Alliance, the European Research Council, and the National Human Genome Research (US).

Authors

Lara Al-Olabi, Satyamaanasa Polubothu, Katherine Dowsett, Katrina A. Andrews, Paulina Stadnik, Agnel P. Joseph, Rachel Knox, Alan Pittman, Graeme Clark, William Baird, Neil Bulstrode, Mary Glover, Kristiana Gordon, Darren Hargrave, Susan M. Huson, Thomas S. Jacques, Gregory James, Hannah Kondolf, Loshan Kangesu, Kim M. Keppler-Noreuil, Amjad Khan, Marjorie J. Lindhurst, Mark Lipson, Sahar Mansour, Justine O'Hara, Caroline Mahon, Anda Mosica, Celia Moss, Aditi Murthy, Juling Ong, Victoria E. Parker, Jean-Baptiste Rivière, Julie C. Sapp, Neil J. Sebire, Rahul Shah, Branavan Sivakumar, Anna Thomas, Alex Virasami, Regula Waelchli, Zhiqiang Zeng, Leslie G. Biesecker, Alex Barnacle, Maya Topf, Robert K. Semple, E. Elizabeth Patton, Veronica A. Kinsler

Tandem bispecific neutralizing antibody eliminates HIV-1 infection in humanized mice

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Abstract

The discovery of an HIV-1 cure remains a medical challenge because the virus rebounds quickly after the cessation of combination antiretroviral drug therapy (cART). Here, we investigate the potential of an engineered tandem bi-specific broadly neutralizing antibody (bs-bnAb) as an innovative product for HIV-1 prophylactic and therapeutic interventions. We discovered that by preserving two scFv binding domains of each parental bnAb, a single-gene-encoded tandem bs-bnAb, namely BiIA-SG, displayed significantly improved breadth and potency. BiIA-SG neutralized all 124 HIV-1 pseudotyped viruses tested, including global subtypes/recombinant forms, transmitted/founder viruses, and variants less or not susceptible to parental and many bnAbs, with an average IC50 value of 0.073 µ/ml (range < 0.001 to 1.03 µg/ml). In humanized mice, an injection of BiIA-SG conferred sterile protection when administered prior to challenges with diverse live HIV-1 stains. Moreover, while BiIA-SG delayed viral rebound in a short-term therapeutic setting when combined with cART, a single injection of AAV-transferred BiIA-SG gene resulted dose-dependently in prolonged in vivo expression of BiIA-SG, which was associated with complete viremia control and subsequent elimination of infected cells in humanized mice. These results warrant the clinical development of BiIA-SG as a promising bs-bnAb-based biomedical intervention for prevention and treatment of HIV-1 infections.

Authors

Xilin Wu, Jia Guo, Mengyue Niu, Minghui An, Li Liu, Hui Wang, Xia Jin, Qi Zhang, Ka Shing Lam, Tongjin Wu, Hua Wang, Qian Wang, Yanhua Du, Jingjing Li, Lin Cheng, Hang Ying Tang, Hong Shang, Linqi Zhang, Paul Zhou, Zhiwei Chen

Surface receptor Toso controls B cell–mediated regulation of T cell immunity

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Abstract

The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model, while, in a chronic inflammatory context, was associated with reduced immunopathological tissue damage. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor (BCR)-activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

Authors

Jinbo Yu, Vu Huy Hoang Duong, Katrin Westphal, Andreas Westphal, Abdulhadi Suwandi, Guntram A. Grassl, Korbinian Brand, Andrew C. Chan, Niko Föger, Kyeong-Hee Lee

CYP3A4 mutation causes vitamin D–dependent rickets type 3

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Abstract

Genetic forms of vitamin D–dependent rickets (VDDRs) are due to mutations impairing activation of vitamin D or decreasing vitamin D receptor responsiveness. Here we describe two unrelated patients with early-onset rickets, reduced serum levels of the vitamin D metabolites 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, and deficient responsiveness to parent and activated forms of vitamin D. Neither patient had a mutation in any genes known to cause VDDR, however, using whole exome sequence analysis we identified a recurrent de novo missense mutation c.902T>C (p.I301T) in CYP3A4 in both subjects that alters the conformation of substrate-recognition-site 4 (SRS-4). In vitro, the mutant CYP3A4 oxidized 1,25-dihydroxyvitamin D with 10-fold greater activity than wild-type CYP3A4 and 2-fold greater activity than CYP24A1, the principal inactivator of vitamin D metabolites. As CYP3A4 mutations have not previously been linked to rickets, these findings provide new insight into vitamin D metabolism, and demonstrate that accelerated inactivation of vitamin D metabolites represents a previously undescribed mechanism for vitamin D deficiency.

Authors

Jeffrey D. Roizen, Dong Li, Lauren O'Lear, Muhammad K. Javaid, Nicholas J. Shaw, Peter R. Ebeling, Hanh H. Nguyen, Christine P. Rodda, Kenneth E. Thummel, Tom D Thacher, Hakon Hakonarson, Michael A. Levine

Killer cell immunoglobulin-like receptor 3DL1 variation modifies HLA-B*57 protection against HIV-1

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Abstract

HLA-B*57 control of HIV involves enhanced CD8+ T cell responses against infected cells, but extensive heterogeneity exists in level of HIV control among B*57+ individuals. Using whole genome sequencing of untreated B*57+ HIV-1 infected controllers and non-controllers, we identified a single variant (rs643347A/G) encoding an isoleucine to valine substitution at position 47 (I47V) of the inhibitory killer cell immunoglobulin-like receptor, KIR3DL1, as the only significant modifier of B*57 protection. The association replicated in an independent cohort and across multiple outcomes. The modifying effect of I47V was confined to B*57:01, and was not observed for the closely related B*57:03. Positions 2, 47, and 54 track one another nearly perfectly, and two KIR3DL1 allotypes differing only at these three positions showed significant differences in binding B*57:01 tetramers, where the protective allotype showed lower binding. Thus, variation in an immune natural killer cell receptor that binds B*57:01 modifies its protection. These data speak to exquisite specificity of KIR-HLA interactions in human health and disease.

Authors

Maureen P. Martin, Vivek Naranbhai, Patrick R. Shea, Ying Qi, Veron Ramsuran, Nicolas Vince, Xiaojiang Gao, Rasmi Thomas, Zabrina L. Brumme, Jonathan M. Carlson, Steven M. Wolinsky, James J. Goedert, Bruce D. Walker, Florencia P. Segal, Steven G. Deeks, David W. Haas, Stephen A. Migueles, Mark Connors, Nelson Michael, Jacques Fellay, Emma Gostick, Sian Llewellyn-Lacey, David A. Price, Bernard A. Lafont, Phillip Pymm, Philippa M. Saunders, Jacqueline Widjaja, Shu Cheng Wong, Julian P. Vivian, Jamie Rossjohn, Andrew G. Brooks, Mary Carrington

DNA repair deficiency sensitizes lung cancer cells to NAD⁺ biosynthesis blockade

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Abstract

Synthetic lethality is an efficient mechanism-based approach to selectively target DNA repair defects. ERCC1 deficiency is frequently found in non-small cell lung cancers, making this DNA repair protein an attractive target for exploiting synthetic lethal approaches in this disease. Using unbiased proteomic and metabolic high-throughput profiling on a unique in-house generated isogenic model of ERCC1 deficiency, we found marked metabolic rewiring of ERCC1-deficient populations, including decreased levels of the metabolite NAD+ and reduced expression of the rate-limiting NAD+ biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT). We further evidenced reduced NAMPT expression in NSCLC samples with low levels of ERCC1. These metabolic alterations were a primary effect of ERCC1 deficiency, and caused selective exquisite sensitivity to small molecule NAMPT inhibitors, both in vitro — ERCC1-deficient cells being approximately 1000 times more sensitive — and in vivo. Using transmission electronic microscopy and functional metabolic studies, we found that ERCC1-deficient cells harbor mitochondrial defects. We propose a model where NAD+ acts as a regulator of ERCC1-deficient NSCLC fitness. These findings open therapeutic opportunities that exploit a yet undescribed nuclear — mitochondrial synthetic lethal relationship in cancer cells, and highlight the potential for targeting DNA repair/metabolic crosstalks for cancer therapy.

Authors

Mehdi Touat, Tony Sourisseau, Nicolas Dorvault, Roman M. Chabanon, Marlène Garrido, Daphné Morel, Dragomir B. Krastev, Ludovic Bigot, Julien Adam, Jessica Frankum, Sylvère Durand, Clement Pontoizeau, Sylvie Souquère, Mei-Shiue Kuo, Sylvie Sauvaigo, Faraz Mardakheh, Alain Sarasin, Ken A. Olaussen, Luc Friboulet, Frédéric Bouillaud, Gérard Pierron, Alan Ashworth, Anne Lombès, Christopher J. Lord, Jean-Charles Soria, Sophie Postel-Vinay

Methyldopa blocks MHC class II binding to disease-specific antigens in autoimmune diabetes

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Abstract

Major histocompatibility (MHC) class II molecules are strongly associated with many autoimmune disorders. In type 1 diabetes, the DQ8 molecule is common, confers significant disease risk and is involved in disease pathogenesis. We hypothesized blocking DQ8 antigen presentation would provide therapeutic benefit by preventing recognition of self-peptides by pathogenic T cells. We used the crystal structure of DQ8 to select drug-like small molecules predicted to bind structural pockets in the MHC antigen-binding cleft. A limited number of the predicted compounds inhibited DQ8 antigen presentation in vitro with one compound preventing insulin autoantibody production and delaying diabetes onset in an animal model of spontaneous autoimmune diabetes. An existing drug of similar structure, methyldopa, specifically blocked DQ8 in recent-onset patients with type 1 diabetes along with reducing inflammatory T cell responses toward insulin, highlighting the relevance of blocking disease-specific MHC class II antigen presentation to treat autoimmunity.

Authors

David A. Ostrov, Aimon Alkanani, Kristen A. McDaniel, Stephanie Case, Erin E. Baschal, Laura Pyle, Samuel Ellis, Bernadette Pöllinger, Katherine J. Seidl, Viral N. Shah, Satish K. Garg, Mark A. Atkinson, Peter A. Gottlieb, Aaron W. Michels

STAT3-enhancing germline mutations contribute to tumor-extrinsic immune evasion

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Abstract

Immune evasion and the suppression of anti-tumor responses during cancer progression are considered hallmarks of cancer and are typically attributed to tumor-derived factors. Although the molecular basis for the crosstalk between tumor and immune cells is an area of active investigation, whether host-specific germline variants can dictate immunosuppressive mechanisms has remained a challenge to address. A commonly occurring germline mutation (c.1162G>A/rs351855 G/A) in the FGFR4 (CD334) gene enhances STAT3 signaling and is associated with poor prognosis and accelerated progression of multiple cancer types. Here, using rs351855 single nucleotide polymorphism (SNP) knock-in transgenic mice and Fgfr4 knockout mice, we reveal the genotype-specific gain of immunological function of suppressing the CD8/CD4+FOXP3+CD25+ve regulatory T cell ratio in vivo. Furthermore, using knock-in transgenic mouse models for lung and breast cancers, we establish the host-specific tumor-extrinsic functions of STAT3-enhancing germline variants in impeding the tumor infiltration of CD8 T cells. Thus, STAT3-enhancing germline receptor variants contribute to immune evasion through their pleiotropic functions in immune cells.

Authors

Daniel Kogan, Alexander Grabner, Christopher Yanucil, Christian Faul, Vijay Kumar Ulaganathan

Loss-of-function CARD8 mutation causes NLRP3 inflammasome activation and Crohn’s disease

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In these studies we evaluated the contribution of the NLRP3 inflammasome to Crohn’s disease (CD) in a kindred containing individuals having a missense mutation in CARD8, a protein known to inhibit this inflammasome. Whole exome sequencing and PCR studies identified that the affected individuals had a V44I mutation in a single allele of the T60 isoform of CARD8. The serum levels of IL-1β in the affected individuals were increased compared with that in healthy controls and their peripheral monocytes produced increased amounts of IL-1β when stimulated by NLRP3 activators. Immunoblot studies probing the basis of these findings showed that mutated T60 CARD8 fails to down-regulate the NLRP3 inflammasome because it does not bind to NLRP3 and inhibit its oligomerization. In addition, these studies showed that mutated T60 CARD8 exerts a dominant negative effect by its capacity to bind to and form oligomers with unmutated T60 or T48 CARD8 that impede their binding to NLRP3. Finally, inflammasome activation studies revealed that intact but not mutated CARD8 prevents NLRP3 deubiquitination and serine dephosphorylation. CD due to a CARD8 mutation was not effectively treated by anti-TNF-α, but did respond to IL-1β inhibitors. Thus, patients with anti-TNF-α-resistant CD may respond to this treatment option.

Authors

Liming Mao, Atsushi Kitani, Morgan Similuk, Andrew J. Oler, Lindsey Albenberg, Judith Kelsen, Atiye Aktay, Martha Quezado, Michael Yao, Kim Montgomery-Recht, Ivan J. Fuss, Warren Strober

Modifier variant of METTL13 suppresses human GAB1-associated profound deafness

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Abstract

A modifier variant can abrogate risk of a monogenic disorder. DFNM1 is a locus on chromosome 1 encoding a dominant suppressor of human DFNB26 recessive, profound deafness. Here, we report that DFNB26 is associated with a substitution (p.Gly116Glu) in the pleckstrin-homology-domain of GAB1, an essential scaffold in the MET/HGF pathway. A dominant substitution (p.Arg544Gln) of METTL13, encoding a predicted methyltransferase, is the DFNM1 suppressor of GAB1-associated deafness. In zebrafish, human METTL13 mRNA harboring the modifier allele rescues the GAB1 associated morphant phenotype. In mouse, GAB1 and METTL13 co-localize in auditory sensory neurons, and METTL13 co-immunoprecipitates with GAB1 and SPRY2, indicating at least a tripartite complex. Expression of MET-signaling genes in human lymphoblastoid cells of individuals homozygous for p.Gly116Glu GAB1 revealed dysregulation of HGF, MET, SHP2, and SPRY2, all of which have reported variants associated with deafness. However, SPRY2 was not dysregulated in normal-hearing humans homozygous for both the GAB1 DFNB26 deafness variant and the dominant METTL13 deafness suppressor, indicating a plausible mechanism of suppression. Identification of METTL13-based modification of MET-signaling provides potential therapeutic strategy for a wide range of associated hearing disorders. Furthermore, MET-signaling is essential for diverse functions in many tissues including the inner ear. Therefore, identification of the modifier of MET-signaling is likely to have broad clinical implications.

Authors

Rizwan Yousaf, Zubair M. Ahmed, Arnaud P.J. Giese, Robert J. Morell, Ayala Lagziel, Alain Dabdoub, Edward R. Wilcox, Sheikh Riazuddin, Thomas B. Friedman, Saima Riazuddin

Pain control through selective chemo-axotomy of centrally projecting TRPV1⁺ sensory neurons

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Abstract

Transient vanilloid potential 1 (TRPV1) agonists are emerging as highly efficacious non-opioid analgesics in preclinical studies. These drugs selectively lesion TRPV1+ primary sensory afferents, which are responsible for the transmission of many noxious stimulus modalities. Resiniferatoxin (RTX) is a very potent and selective TRPV1 agonist and is a promising candidate for treating many types of pain. Recent work establishing intrathecal application of RTX for the treatment of pain resulting from advanced cancer has demonstrated profound analgesia in client-owned dogs with osteosarcoma. The present study uses transcriptomics and histochemistry to examine the molecular mechanism of RTX action in rats, in clinical canine subjects, and in one human subject with advanced cancer treated for pain using intrathecal RTX. In all three species we observe a strong analgesic action, yet this was accompanied by limited transcriptional alterations at the level of the DRG. Functional and neuroanatomical studies demonstrated that intrathecal RTX largely spares susceptible neuronal perikarya, which remain active peripherally, but unable to transmit signals to the spinal cord. The results demonstrate that central chemo-axotomy of the TRPV1+ afferents underlies RTX analgesia and refine the neurobiology underlying effective clinical use of TRPV1 agonists for pain control.

Authors

Matthew R. Sapio, John K. Neubert, Danielle M. LaPaglia, Dragan Maric, Jason M. Keller, Stephen J. Raithel, Eric L. Rohrs, Ethan M. Anderson, John A. Butman, Robert M. Caudle, Dorothy C. Brown, John D. Heiss, Andrew J. Mannes, Michael J. Iadarola

FoxO transcription factors are required for hepatic HDL-cholesterol clearance

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Abstract

Insulin resistance and type 2 diabetes are associated with low levels of high-density lipoprotein-cholesterol (HDL-C). The insulin-repressible FoxO transcription factors are potential mediators of insulin’s effect on HDL-C. FoxOs mediate a substantial portion of insulin-regulated transcription, and poor FoxO repression is thought to contribute to the excessive glucose production in diabetes. In this work, we show that mice with liver-specific triple FoxO knockout (L-FoxO1,3,4), which are known to have reduced hepatic glucose production, also have increased HDL-C. This was associated with decreased expression of HDL-C clearance factors, scavenger receptor class B type I (SR-BI) and hepatic lipase, and defective selective uptake of HDL-cholesteryl ester by the liver. The phenotype could be rescued by re-expression of SR-BI. These findings demonstrate that hepatic FoxOs are required for cholesterol homeostasis and HDL-mediated reverse cholesterol transport to the liver.

Authors

Samuel X. Lee, Markus Heine, Christian Schlein, Rajasekhar Ramakrishnan, Jing Liu, Gabriella Belnavis, Ido Haimi, Alexander W. Fischer, Henry Ginsberg, Joerg Heeren, Franz Rinninger, Rebecca A. Haeusler

Ribonuclease inhibitor 1 regulates erythropoiesis by controlling GATA1 mRNA translation

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Abstract

Ribosomal proteins (RP) regulate specific gene expression by selectively translating subsets of mRNAs. Indeed, in Diamond–Blackfan anaemia and 5q- syndrome, mutations in RP genes lead to a specific defect in erythroid gene translation and cause anaemia. Little is known about the molecular mechanisms of selective mRNA translation and involvement of ribosomal-associated factors in this process. Ribonuclease inhibitor (RNH1) is an ubiquitously expressed protein that binds to and inhibits pancreatic-type ribonucleases. Here we report that RNH1 binds to ribosomes and regulates erythropoiesis by controlling translation of the erythroid transcription factor GATA1. Rnh1-deficient mice die between embryonic days E8.5 to E10 due to impaired production of mature erythroid cells from progenitor cells. In Rnh1-deficient embryos, mRNA levels of Gata1 are normal, but GATA1 protein levels are decreased. At the molecular level, we found that RNH1 binds to the 40S subunit of ribosomes and facilitates polysome formation on Gata1 mRNA to confer transcript-specific translation. Further, RNH1 knock down in human CD34+ progenitor cells decreased erythroid differentiation without affecting myelopoiesis. Our results reveal an unsuspected role for RNH1 in the control of GATA1 mRNA translation and erythropoiesis.

Authors

Vijaykumar Chennupati, Diogo F.T. Veiga, Kendle M. Maslowski, Nicola Andina, Aubry Tardivel, Eric Chi-Wang Yu, Martina Stilinovic, Cedric Simillion, Michel A. Duchosal, Manfredo Quadroni, Irene Roberts, Vijay G. Sankaran, H. Robson MacDonald, Nicolas Fasel, Anne Angelillo-Scherrer, Pascal Schneider, Trang Hoang, Ramanjaneyulu Allam

Tuberous sclerosis complex–associated CNS abnormalities depend on hyperactivation of mTORC1 and Akt

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Abstract

Tuberous sclerosis complex (TSC) is a dominantly inherited disease, caused by hyperactivation of the mTORC1 pathway and characterized by the development of hamartomas and benign tumors, also in the brain. Among the neurological manifestations associated with TSC, the tumor progression of static subependymal nodules (SENs) into subependymal giant cell astrocytomas (SEGAs) is one of the major causes of morbidity and shortened life expectancy. To date, mouse modeling has failed in reproducing these two lesions. Here we report that simultaneous hyperactivation of mTORC1 and Akt pathways by codeletion of Tsc1 and Pten, selectively in postnatal neural stem cells (pNSCs), is required for the formation of bona fide SENs and SEGAs. Notably, both lesions closely recapitulate the pathognomonic morphological and molecular features of the corresponding human abnormalities. The establishment of long-term expanding pNSC lines from mouse SENs and SEGAs made possible the identification of mTORC2 as one of the mediators conferring tumorigenic potential to SEGA pNSCs. Of note, in spite of concurrent Akt hyperactivation in mouse brain lesions, single mTOR inhibition by rapamycin was sufficient to strongly impair mouse SEGA growth. This study provides the first evidence that, concomitant with mTORC1 hyperactivation, sustained activation of Akt and mTORC2 in pNSCs is a mandatory step for the induction of SENs and SEGAs and, at the same time, makes available an unprecedented NSC-based in vivo/in vitro model to be exploited for identifying actionable targets in TSC.

Authors

Paola Zordan, Manuela Cominelli, Federica Cascino, Elisa Tratta, Pietro L. Poliani, Rossella Galli

A controlled human malaria infection model enabling evaluation of transmission-blocking interventions

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Abstract

BACKGROUND. Drugs and vaccines that can interrupt the transmission of Plasmodium falciparum will be important for malaria control and elimination. However, models for early clinical evaluation of candidate transmission-blocking interventions are currently unavailable. Here we describe a new model for evaluating malaria transmission from humans to Anopheles mosquitoes using controlled human malaria infection (CHMI). METHODS. Seventeen healthy malaria-naïve volunteers underwent CHMI by intravenous inoculation of P. falciparum-infected erythrocytes to initiate blood-stage infection. Seven to eight days after inoculation participants received piperaquine (480 mg) to attenuate asexual parasite replication while allowing gametocytes to develop and mature. Primary endpoints were development of gametocytemia, the transmissibility of gametocytes from humans to mosquitoes, and the safety and tolerability of the CHMI transmission model. To investigate in-vivo gametocytocidal drug activity in this model, participants were either given an experimental antimalarial, artefenomel (500 mg), a known gametocytocidal drug, primaquine (15 mg), or remained untreated during the period of gametocyte carriage. RESULTS. Male and female gametocytes were detected in all participants, and transmission to mosquitoes was achieved from 8/11 (73%) participants evaluated. Compared to untreated controls (n = 7), primaquine (15 mg, n = 5) significantly reduced gametocyte burden (P = 0.01), while artefenomel (500 mg, n = 4) had no effect. Adverse events (AEs) were mostly mild or moderate. Three AEs were assessed as severe — fatigue, elevated alanine aminotransferase, and elevated aspartate aminotransferase — and were attributed to malaria infection. Transaminase elevations were transient, asymptomatic, and resolved without intervention. CONCLUSION. We report the safe and reproducible induction of P. falciparum gametocytes in healthy malaria-naïve volunteers at densities infectious to mosquitoes, thereby demonstrating the potential for evaluating transmission-blocking interventions in this model. TRIAL REGISTRATION. ClinicalTrials.gov NCT02431637 and NCT02431650 FUNDING. Bill & Melinda Gates Foundation

Authors

Katharine A. Collins, Claire Y.T. Wang, Matthew Adams, Hayley Mitchell, Melanie Rampton, Suzanne Elliott, Isaie J. Reuling, Teun Bousema, Robert Sauerwein, Stephan Chalon, Jörg J. Möhrle, James S. McCarthy

Hypoglycemia unawareness in type 1 diabetes suppresses brain responses to hypoglycemia

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Abstract

BACKGROUND. Amongst non-diabetic individuals, mild glucose decrements alter brain activity in regions linked to reward, motivation and executive control. Whether these effects differ in T1DM patients with and without hypoglycemia awareness remains unclear. METHODS. 42 individuals (13 healthy control subjects (HC), 16 T1DM individuals with hypoglycemia awareness (T1DM-Aware) and 13 T1DM individuals with hypoglycemia unawareness (T1DM-Unaware)) underwent BOLD fMRI brain imaging during a 2-step hyperinsulinemic euglycemic (90 mg/dl)-hypoglycemic (60 mg/dl) clamp for assessment of neural responses to mild hypoglycemia. RESULTS. Mild hypoglycemia in HC altered activity in the caudate, insula, prefrontal cortex, and angular gyrus, whereas T1DM-Aware subjects showed no caudate and insula changes, but showed altered activation patterns in the prefrontal cortex and angular gyrus. Most strikingly, in direct contrast to HC and T1DM-Aware subjects, T1DM-Unaware subjects failed to show any hypoglycemia-induced changes in brain activity. These findings were also associated with blunted hormonal counterregulatory responses and hypoglycemia symptoms scores during mild hypoglycemia. CONCLUSION. In T1DM, and in particular T1DM-Unaware patients, there is a progressive blunting of brain responses in cortico-striatal and fronto-parietal neurocircuits in response to mild-moderate hypoglycemia. These findings have implications for understanding why individuals with impaired hypoglycemia awareness fail to respond appropriately to falling blood glucose levels. FUNDING. This study was supported in part by grants from the NIH R01DK020495 and P30 DK045735 (Sherwin), K23DK109284 (Hwang), K08AA023545 (Seo), the Yale Center for Clinical Investigation supported by the Clinical Translational Science Award (UL1 RR024139).

Authors

Janice Jin Hwang, Lisa Parikh, Cheryl Lacadie, Dongju Seo, Wai Lam, Muhammad Hamza, Christian Schmidt, Feng Dai, Anne-Sophie Sejling, Renata Belfort-DeAguiar, R. Todd Constable, Rajita Sinha, Robert Sherwin