Long-acting anti-HIV products can substantively change the standard of care for patients with HIV/AIDS. To this end, hydrophobic antiretroviral drugs (ARVs) were recently developed for parenteral administration at monthly or longer intervals. While shorter-acting hydrophilic drugs can be made into nanocarrier-encased prodrugs, the nanocarrier encasement must be boosted to establish long-acting ARV depots. The mixed-lineage kinase 3 (MLK-3) inhibitor URMC-099 provides this function by affecting autophagy. Here, we have shown that URMC-099 facilitates ARV sequestration and its antiretroviral responses by promoting the nuclear translocation of the transcription factor EB (TFEB). In monocyte-derived macrophages, URMC-099 induction of autophagy led to retention of nanoparticles containing the antiretroviral protease inhibitor atazanavir. These nanoparticles were localized within macrophage autophagosomes, leading to a 4-fold enhancement of mitochondrial and cell vitality. In rodents, URMC-099 activation of autophagy led to 50-fold increases in the plasma drug concentration of the viral integrase inhibitor dolutegravir. These data paralleled URMC-099–mediated induction of autophagy and the previously reported antiretroviral responses in HIV-1–infected humanized mice. We conclude that pharmacologic induction of autophagy provides a means to extend the action of a long-acting, slow, effective release of antiretroviral therapy.
Divya Prakash Gnanadhas, Prasanta K. Dash, Brady Sillman, Aditya N. Bade, Zhiyi Lin, Diana L. Palandri, Nagsen Gautam, Yazen Alnouti, Harris A. Gelbard, JoEllyn McMillan, R. Lee Mosley, Benson Edagwa, Howard E. Gendelman, Santhi Gorantla
Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS.
Brian P. Daniels, Harsha Jujjavarapu, Douglas M. Durrant, Jessica L. Williams, Richard R. Green, James P. White, Helen M. Lazear, Michael Gale Jr., Michael S. Diamond, Robyn S. Klein
The mechanism by which leptin reverses diabetic ketoacidosis (DKA) is unknown. We examined the acute insulin-independent effects of leptin replacement therapy in a streptozotocin-induced rat model of DKA. Leptin infusion reduced rates of lipolysis, hepatic glucose production (HGP), and hepatic ketogenesis by 50% within 6 hours and were independent of any changes in plasma glucagon concentrations; these effects were abrogated by coinfusion of corticosterone. Treating leptin- and corticosterone-infused rats with an adipose triglyceride lipase inhibitor blocked corticosterone-induced increases in plasma glucose concentrations and rates of HGP and ketogenesis. Similarly, adrenalectomized type 1 diabetic (T1D) rats exhibited decreased rates of lipolysis, HGP, and ketogenesis; these effects were reversed by corticosterone infusion. Leptin-induced decreases in lipolysis, HGP, and ketogenesis in DKA were also nullified by relatively small increases (15 to 70 pM) in plasma insulin concentrations. In contrast, the chronic glucose-lowering effect of leptin in a STZ-induced mouse model of poorly controlled T1D was associated with decreased food intake, reduced plasma glucagon and corticosterone concentrations, and decreased ectopic lipid (triacylglycerol/diacylglycerol) content in liver and muscle. Collectively, these studies demonstrate marked differences in the acute insulin-independent effects by which leptin reverses fasting hyperglycemia and ketoacidosis in a rodent model of DKA versus the chronic pleotropic effects by which leptin reverses hyperglycemia in a non-DKA rodent model of T1D.
Rachel J. Perry, Liang Peng, Abudukadier Abulizi, Lynn Kennedy, Gary W. Cline, Gerald I. Shulman
Olfactory dysfunction is broadly associated with neurodevelopmental and neurodegenerative diseases and predicts increased mortality rates in healthy individuals. Conventional measurements of olfactory health assess odor processing pathways within the brain and provide a limited understanding of primary odor detection. Quantification of the olfactory sensory neurons (OSNs), which detect odors within the nasal cavity, would provide insight into the etiology of olfactory dysfunction associated with disease and mortality. Notably, OSNs are continually replenished by adult neurogenesis in mammals, including humans, so OSN measurements are primed to provide specialized insights into neurological disease. Here, we have evaluated a PET radiotracer, [11C]GV1-57, that specifically binds mature OSNs and quantifies the mature OSN population in vivo. [11C]GV1-57 monitored native OSN population dynamics in rodents, detecting OSN generation during postnatal development and aging-associated neurodegeneration. [11C]GV1-57 additionally measured rates of neuron regeneration after acute injury and early-stage OSN deficits in a rodent tauopathy model of neurodegenerative disease. Preliminary assessment in nonhuman primates suggested maintained uptake and saturable binding of [18F]GV1-57 in primate nasal epithelium, supporting its translational potential. Future applications for GV1-57 include monitoring additional diseases or conditions associated with olfactory dysregulation, including cognitive decline, as well as monitoring effects of neuroregenerative or neuroprotective therapeutics.
Genevieve C. Van de Bittner, Misha M. Riley, Luxiang Cao, Janina Ehses, Scott P. Herrick, Emily L. Ricq, Hsiao-Ying Wey, Michael J. O’Neill, Zeshan Ahmed, Tracey K. Murray, Jaclyn E. Smith, Changning Wang, Frederick A. Schroeder, Mark W. Albers, Jacob M. Hooker
We recently demonstrated that selective expression of the Rho GTPase-activating protein ARHGAP42 in smooth muscle cells (SMCs) controls blood pressure by inhibiting RhoA-dependent contractility, providing a mechanism for the blood pressure–associated locus within the
Xue Bai, Kevin D. Mangum, Rachel A. Dee, George A. Stouffer, Craig R. Lee, Akinyemi Oni-Orisan, Cam Patterson, Jonathan C. Schisler, Anthony J. Viera, Joan M. Taylor, Christopher P. Mack
Parkinson’s disease (PD) patients experience loss of normal motor function (hypokinesia), but can develop uncontrollable movements known as dyskinesia upon treatment with L-DOPA. Poverty or excess of movement in PD has been attributed to overactivity of striatal projection neurons forming either the indirect (iSPNs) or the direct (dSPNs) pathway, respectively. Here, we investigated the two pathways’ contribution to different motor features using SPN type–specific chemogenetic stimulation in rodent models of PD (PD mice) and L-DOPA–induced dyskinesia (LID mice). Using the activatory Gq-coupled human M3 muscarinic receptor (hM3Dq), we found that chemogenetic stimulation of dSPNs mimicked, while stimulation of iSPNs abolished the therapeutic action of L-DOPA in PD mice. In LID mice, hM3Dq stimulation of dSPNs exacerbated dyskinetic responses to L-DOPA, while stimulation of iSPNs inhibited these responses. In the absence of L-DOPA, only chemogenetic stimulation of dSPNs mediated through the Gs-coupled modified rat muscarinic M3 receptor (rM3Ds) induced appreciable dyskinesia in PD mice. Combining D2 receptor agonist treatment with rM3Ds-dSPN stimulation reproduced all symptoms of LID. These results demonstrate that dSPNs and iSPNs oppositely modulate both therapeutic and dyskinetic responses to dopamine replacement therapy in PD. We also show that chemogenetic stimulation of different signaling pathways in dSPNs leads to markedly different motor outcomes. Our findings have important implications for the design of effective antiparkinsonian and antidyskinetic drug therapies.
Cristina Alcacer, Laura Andreoli, Irene Sebastianutto, Johan Jakobsson, Tim Fieblinger, Maria Angela Cenci
Sensory neurons have the capacity to produce, release, and respond to acetylcholine (ACh), but the functional role of cholinergic systems in adult mammalian peripheral sensory nerves has not been established. Here, we have reported that neurite outgrowth from adult sensory neurons that were maintained under subsaturating neurotrophic factor conditions operates under cholinergic constraint that is mediated by muscarinic receptor–dependent regulation of mitochondrial function via AMPK. Sensory neurons from mice lacking the muscarinic ACh type 1 receptor (M1R) exhibited enhanced neurite outgrowth, confirming the role of M1R in tonic suppression of axonal plasticity. M1R-deficient mice made diabetic with streptozotocin were protected from physiological and structural indices of sensory neuropathy. Pharmacological blockade of M1R using specific or selective antagonists, pirenzepine, VU0255035, or muscarinic toxin 7 (MT7) activated AMPK and overcame diabetes-induced mitochondrial dysfunction in vitro and in vivo. These antimuscarinic drugs prevented or reversed indices of peripheral neuropathy, such as depletion of sensory nerve terminals, thermal hypoalgesia, and nerve conduction slowing in diverse rodent models of diabetes. Pirenzepine and MT7 also prevented peripheral neuropathy induced by the chemotherapeutic agents dichloroacetate and paclitaxel or HIV envelope protein gp120. As a variety of antimuscarinic drugs are approved for clinical use against other conditions, prompt translation of this therapeutic approach to clinical trials is feasible.
Nigel A. Calcutt, Darrell R. Smith, Katie Frizzi, Mohammad Golam Sabbir, Subir K. Roy Chowdhury, Teresa Mixcoatl-Zecuatl, Ali Saleh, Nabeel Muttalib, Randy Van der Ploeg, Joseline Ochoa, Allison Gopaul, Lori Tessler, Jürgen Wess, Corinne G. Jolivalt, Paul Fernyhough
Congenital tufting enteropathy (CTE) is a severe autosomal recessive human diarrheal disorder with characteristic intestinal epithelial dysplasia. CTE can be caused by mutations in genes encoding EpCAM, a putative adhesion molecule, and HAI-2, a cell surface protease inhibitor. A similar phenotype occurs in mice whose intestinal epithelial cells (IECs) fail to express the tight junction–associated protein claudin-7. EpCAM stabilizes claudin-7 in IECs, and HAI-2 regulates the cell surface serine protease matriptase, a known modifier of intestinal epithelial physiology. Therefore, we hypothesized that HAI-2, matriptase, EpCAM, and claudin-7 were functionally linked. Herein we have demonstrated that active matriptase cleaves EpCAM after Arg80 and that loss of HAI-2 in IECs led to unrestrained matriptase activity and efficient cleavage of EpCAM. Cleavage of EpCAM decreased its ability to associate with claudin-7 and targeted it for internalization and lysosomal degradation in conjunction with claudin-7. CTE-associated HAI-2 mutant proteins exhibited reduced ability to inhibit matriptase and also failed to efficiently stabilize claudin-7 in IECs. These results identify EpCAM as a substrate of matriptase and link HAI-2, matriptase, EpCAM, and claudin-7 in a functionally important pathway that causes disease when it is dysregulated.
Chuan-Jin Wu, Xu Feng, Michael Lu, Sohshi Morimura, Mark C. Udey
Hepatic steatosis is caused by metabolic imbalances that could be explained in part by an increase in de novo lipogenesis that results from increased sterol element binding protein 1 (SREBP-1) activity. The nuclear receptor liver receptor homolog 1 (LRH-1) is an important regulator of intermediary metabolism in the liver, but its role in regulating lipogenesis is not well understood. Here, we have assessed the contribution of LRH-1 SUMOylation to the development of nonalcoholic fatty liver disease (NAFLD). Mice expressing a SUMOylation-defective mutant of LRH-1 (LRH-1 K289R mice) developed NAFLD and early signs of nonalcoholic steatohepatitis (NASH) when challenged with a lipogenic, high-fat, high-sucrose diet. Moreover, we observed that the LRH-1 K289R mutation induced the expression of oxysterol binding protein-like 3 (OSBPL3), enhanced SREBP-1 processing, and promoted de novo lipogenesis. Mechanistically, we demonstrated that ectopic expression of OSBPL3 facilitates SREBP-1 processing in WT mice, while silencing hepatic
Sokrates Stein, Vera Lemos, Pan Xu, Hadrien Demagny, Xu Wang, Dongryeol Ryu, Veronica Jimenez, Fatima Bosch, Thomas F. Lüscher, Maaike H. Oosterveer, Kristina Schoonjans
Compromised apoptotic signaling is a prerequisite for tumorigenesis. The design of effective therapies for cancer treatment depends on a comprehensive understanding of the mechanisms that govern cell survival. The antiapoptotic proteins of the BCL-2 family are key regulators of cell survival and are frequently overexpressed in malignancies, leading to increased cancer cell survival. Unlike BCL-2 and BCL-XL, the closest antiapoptotic relative BCL-W is required for spermatogenesis, but was considered dispensable for all other cell types. Here, however, we have exposed a critical role for BCL-W in B cell survival and lymphomagenesis. Loss of
Clare M. Adams, Annette S. Kim, Ramkrishna Mitra, John K. Choi, Jerald Z. Gong, Christine M. Eischen
Orphan GPCRs provide an opportunity to identify potential pharmacological targets, yet their expression patterns and physiological functions remain challenging to elucidate. Here, we have used a genetically engineered knockin reporter mouse to map the expression pattern of the
Daniel O. Kechele, R. Eric Blue, Bailey Zwarycz, Scott T. Espenschied, Amanda T. Mah, Marni B. Siegel, Charles M. Perou, Shengli Ding, Scott T. Magness, P. Kay Lund, Kathleen M. Caron
Patients with leukemia who receive a T cell–depleted allogeneic stem cell graft followed by postponed donor lymphocyte infusion (DLI) can experience graft-versus-leukemia (GVL) reactivity, with a lower risk of graft-versus-host disease (GVHD). Here, we have investigated the magnitude, diversity, and specificity of alloreactive CD8 T cells in patients who developed GVL reactivity after DLI in the absence or presence of GVHD. We observed a lower magnitude and diversity of CD8 T cells for minor histocompatibility antigens (MiHAs) in patients with selective GVL reactivity without GVHD. Furthermore, we demonstrated that MiHA-specific T cell clones from patients with selective GVL reactivity showed lower reactivity against nonhematopoietic cells, even when pretreated with inflammatory cytokines. Expression analysis of MiHA-encoding genes showed that similar types of antigens were recognized in both patient groups, but in patients who developed GVHD, T cell reactivity was skewed to target broadly expressed MiHAs. As an inflammatory environment can render nonhematopoietic cells susceptible to T cell recognition, prevention of such circumstances favors induction of selective GVL reactivity without development of GVHD.
Cornelis A.M. van Bergen, Simone A.P. van Luxemburg-Heijs, Liesbeth C. de Wreede, Matthijs Eefting, Peter A. von dem Borne, Peter van Balen, Mirjam H.M. Heemskerk, Arend Mulder, Fransiscus H.J. Claas, Marcelo A Navarrete, Wilhelmina M. Honders, Caroline E. Rutten, Hendrik Veelken, Inge Jedema, Constantijn J.M. Halkes, Marieke Griffioen, J.H. Frederik Falkenburg
MicroRNAs (miRs) are tightly regulated in the immune system, and aberrant expression of miRs often results in hematopoietic malignancies and autoimmune diseases. Previously, it was suggested that elevated levels of miR-27 in T cells isolated from patients with multiple sclerosis facilitate disease progression by inhibiting Th2 immunity and promoting pathogenic Th1 responses. Here we have demonstrated that, although mice with T cell–specific overexpression of miR-27 harbor dysregulated Th1 responses and develop autoimmune pathology, these disease phenotypes are not driven by miR-27 in effector T cells in a cell-autonomous manner. Rather, dysregulation of Th1 responses and autoimmunity resulted from a perturbed Treg compartment. Excessive miR-27 expression in murine T cells severely impaired Treg differentiation. Moreover, Tregs with exaggerated miR-27–mediated gene regulation exhibited diminished homeostasis and suppressor function in vivo. Mechanistically, we determined that miR-27 represses several known as well as previously uncharacterized targets that play critical roles in controlling multiple aspects of Treg biology. Collectively, our data show that miR-27 functions as a key regulator in Treg development and function and suggest that proper regulation of miR-27 is pivotal to safeguarding Treg-mediated immunological tolerance.
Leilani O. Cruz, Somaye Sadat Hashemifar, Cheng-Jang Wu, Sunglim Cho, Duc T. Nguyen, Ling-Li Lin, Aly Azeem Khan, Li-Fan Lu
Failure of trabecular myocytes to undergo appropriate cell cycle withdrawal leads to ventricular noncompaction and heart failure. Signaling of growth factor receptor ERBB2 is critical for myocyte proliferation and trabeculation. However, the mechanisms underlying appropriate downregulation of trabecular ERBB2 signaling are little understood. Here, we have found that the endocytic adaptor proteins NUMB and NUMBL were required for downregulation of ERBB2 signaling in maturing trabeculae. Loss of NUMB and NUMBL resulted in a partial block of late endosome formation, resulting in sustained ERBB2 signaling and STAT5 activation. Unexpectedly, activated STAT5 overrode Hippo-mediated inhibition and drove YAP1 to the nucleus. Consequent aberrant cardiomyocyte proliferation resulted in ventricular noncompaction that was markedly rescued by heterozygous loss of function of either ERBB2 or YAP1. Further investigations revealed that NUMB and NUMBL interacted with small GTPase Rab7 to transition ERBB2 from early to late endosome for degradation. Our studies provide insight into mechanisms by which NUMB and NUMBL promote cardiomyocyte cell cycle withdrawal and highlight previously unsuspected connections between pathways that are important for cardiomyocyte cell cycle reentry, with relevance to ventricular noncompaction cardiomyopathy and regenerative medicine.
Maretoshi Hirai, Yoh Arita, C. Jane McGlade, Kuo-Fen Lee, Ju Chen, Sylvia M. Evans
Myotonic dystrophy type I (DM1) is a disabling multisystemic disease that predominantly affects skeletal muscle. It is caused by expanded CTG repeats in the 3′-UTR of the dystrophia myotonica protein kinase (
Marielle Brockhoff, Nathalie Rion, Kathrin Chojnowska, Tatiana Wiktorowicz, Christopher Eickhorst, Beat Erne, Stephan Frank, Corrado Angelini, Denis Furling, Markus A. Rüegg, Michael Sinnreich, Perrine Castets
The current frontline symptomatic treatment for Alzheimer’s disease (AD) is whole-body upregulation of cholinergic transmission via inhibition of acetylcholinesterase. This approach leads to profound dose-related adverse effects. An alternative strategy is to selectively target muscarinic acetylcholine receptors, particularly the M1 muscarinic acetylcholine receptor (M1 mAChR), which was previously shown to have procognitive activity. However, developing M1 mAChR–selective orthosteric ligands has proven challenging. Here, we have shown that mouse prion disease shows many of the hallmarks of human AD, including progressive terminal neurodegeneration and memory deficits due to a disruption of hippocampal cholinergic innervation. The fact that we also show that muscarinic signaling is maintained in both AD and mouse prion disease points to the latter as an excellent model for testing the efficacy of muscarinic pharmacological entities. The memory deficits we observed in mouse prion disease were completely restored by treatment with benzyl quinolone carboxylic acid (BQCA) and benzoquinazoline-12 (BQZ-12), two highly selective positive allosteric modulators (PAMs) of M1 mAChRs. Furthermore, prolonged exposure to BQCA markedly extended the lifespan of diseased mice. Thus, enhancing hippocampal muscarinic signaling using M1 mAChR PAMs restored memory loss and slowed the progression of mouse prion disease, indicating that this ligand type may have clinical benefit in diseases showing defective cholinergic transmission, such as AD.
Sophie J. Bradley, Julie-Myrtille Bourgognon, Helen E. Sanger, Nicholas Verity, Adrian J. Mogg, David J. White, Adrian J. Butcher, Julie A. Moreno, Colin Molloy, Timothy Macedo-Hatch, Jennifer M. Edwards, Jurgen Wess, Robert Pawlak, David J. Read, Patrick M. Sexton, Lisa M. Broad, Joern R. Steinert, Giovanna R. Mallucci, Arthur Christopoulos, Christian C. Felder, Andrew B. Tobin
Aminoglycosides (AGs) are broad-spectrum antibiotics that are associated with kidney damage, balance disorders, and permanent hearing loss. This damage occurs primarily by killing of proximal tubule kidney cells and mechanosensory hair cells, though the mechanisms underlying cell death are not clear. Imaging molecules of interest in living cells can elucidate how molecules enter cells, traverse intracellular compartments, and interact with sites of activity. Here, we have imaged fluorescently labeled AGs in live zebrafish mechanosensory hair cells. We determined that AGs enter hair cells via both nonendocytic and endocytic pathways. Both routes deliver AGs from the extracellular space to lysosomes, and structural differences between AGs alter the efficiency of this delivery. AGs with slower delivery to lysosomes were immediately toxic to hair cells, and impeding lysosome delivery increased AG-induced death. Therefore, pro-death cascades induced at early time points of AG exposure do not appear to derive from the lysosome. Our findings help clarify how AGs induce hair cell death and reveal properties that predict toxicity. Establishing signatures for AG toxicity may enable more efficient evaluation of AG treatment paradigms and structural modifications to reduce hair cell damage. Further, this work demonstrates how following fluorescently labeled drugs at high resolution in living cells can reveal important details about how drugs of interest behave.
Dale W. Hailey, Robert Esterberg, Tor H. Linbo, Edwin W. Rubel, David W. Raible
Controlled angiogenesis and lymphangiogenesis are essential for tissue development, function, and repair. However, aberrant neovascularization is an essential pathogenic mechanism in many human diseases, including diseases involving tumor growth and survival. Here, we have demonstrated that mice deficient in C-type lectin family 14 member A (CLEC14A) display enhanced angiogenic sprouting and hemorrhage as well as enlarged jugular lymph sacs and lymphatic vessels. CLEC14A formed a complex with VEGFR-3 in endothelial cells (ECs), and CLEC14A KO resulted in a marked reduction in VEGFR-3 that was concomitant with increases in VEGFR-2 expression and downstream signaling. Implanted tumor growth was profoundly reduced in CLEC14A-KO mice compared with that seen in WT littermates, but tumor-bearing CLEC14A-KO mice died sooner. Tumors in CLEC14A-KO mice had increased numbers of nonfunctional blood vessels and severe hemorrhaging. Blockade of VEGFR-2 signaling suppressed these vascular abnormalities and enhanced the survival of tumor-bearing CLEC14A-KO mice. We conclude that CLEC14A acts in vascular homeostasis by fine-tuning VEGFR-2 and VEGFR-3 signaling in ECs, suggesting its relevance in the pathogenesis of angiogenesis-related human disorders.
Sungwoon Lee, Seung-Sik Rho, Hyojin Park, Jeong Ae Park, Jihye Kim, In-Kyu Lee, Gou Young Koh, Naoki Mochizuki, Young-Myeong Kim, Young-Guen Kwon
Gsα, encoded by
Min Chen, Yogendra B. Shrestha, Brandon Podyma, Zhenzhong Cui, Benedetta Naglieri, Hui Sun, Thuy Ho, Eric A. Wilson, Yong-Qi Li, Oksana Gavrilova, Lee S. Weinstein
Type 2 diabetes is thought to involve a compromised β cell differentiation state, but the mechanisms underlying this dysfunction remain unclear. Here, we report a key role for the TF PAX6 in the maintenance of adult β cell identity and function. PAX6 was downregulated in β cells of diabetic
Avital Swisa, Dana Avrahami, Noa Eden, Jia Zhang, Eseye Feleke, Tehila Dahan, Yamit Cohen-Tayar, Miri Stolovich-Rain, Klaus H. Kaestner, Benjamin Glaser, Ruth Ashery-Padan, Yuval Dor