MMI 415-515 NM 23iii23-1 (2).pdf

Neurotropic viruses Christopher Power MD Departments of Medicine (Neurology), Psychiatry and Medical Microbiology & Immunology University of Alberta MMI 415/515 Outline 1) Familiarity with neurotropic viral infections’ impact and emerging neurological infections impact viruses onbrain. of - -...

Neurotropic viruses Christopher Power MD Departments of Medicine (Neurology), Psychiatry and Medical Microbiology & Immunology University of Alberta MMI 415/515 Outline 1) Familiarity with neurotropic viral infections’ impact and emerging neurological infections impact viruses onbrain. of - - emerging infections 2) The neural cells that are permissive to viral infection 3) A common neurological infection: HIV-associated neurocognitive disorder (HAND) 4) A lethal neurovirological disease: JC virus-associated Progressive Multifocal Leukoencephalopathy (PML) 4) Emerging neurovirological infections: human pegivirus and SARS-CoV-2 5) Multiple sclerosis: a virus-associated disease? Disclosures Introduction • Neurological infections are among the top six causes of neurological disease worldwide with substantial morbidity/mortality. 1 These largelyForHIV+ other infections • Major concerns: apPltOOthers (1) the development of drug resistant viruses, (2) the increasing number of immunocompromised human populations, genetics. (3) the rising number of diseases previously considered rare (e.g., Zika virus). concern for HIV+ other -> viruses that impact NS. -> • Education, surveillance, development of new drugs and vaccines are essential to prevent and treat resurging 2 Infections and emerging neurological infectious diseases. coming that are baCK. Neurological disorders: public health challenges (2006) WHO Press Neurological infections • Unique aspects of CNS infections: - brainis a complex structure 1. Localization of the infection dictates the clinical presentation (CNS vs. infectionis in PNS). Depending Neurological MANifeStAtiONS. GANGE 2. Brain is an immune privileged organ Blood-brain barrier protection DRAMM.  innate (macrophages, neutrophils) vs. adaptive (CTL and traficking Abs) immunity. DRAIN. DIOOD onthere - You get the NS Of Traffic cells infect inthe # There are leukocytes FROM TO WHAtistheMOSt COMROneMergency infection? - aviral infection Common neurological infections HSV2-spital corddisease C INDIA are HerpesCencephalits ↑ MOSCOMM. Neuroinfec Shingle • Viruses: HSV, VZV, HIV, WNV, rabies ↳ • Bacteria: N. meningitides, S. pneumoniae, M. tuberculosis, Borreliosis (Lyme disease). • Fungal: Cryptococcus neoformans, Histoplasmosis, Coccidiomycosis • Parasite: Malaria, Toxoplasma gondi, Cysticercosis • Prions: Creutzfeldt-Jakob disease. Gerstmann-Stroessler Syndrome Causes Varicellazoster virus chickenpox disease. I - HSV 1- Causes Encephalitis HSV -2 - Causes spinal cord disease Varicellla Zoster Virus - a range of neurological symptoms --> most common neurological infection as it causes shingles, shingles is the reactivation of the chicken pox virus in peripheral nervous system HIV : very common neurological illness WNV -used to be common in north America Causes Brain disease Origins of human viral infections How did the viral infections make their way to the humans? Are these acute or chronic infections ? Rabies: A direct infection and can spread through dogs, skunks and foxes and stray dogs in the south east Asia Ebola : bats -- non -human primates -- humans Dengue : big problem in the caribbean -- non primates - humans HIV ; classic xenoinfection Hepatitis c: very common infection in humans maybe dogs? EDOIC NOHCBATS) HUMOH - primates Direct infection in HUAHS StrAYDOGS incatrib. Wolfe et al, Nature 447:279-83 (2007) Emerging neurological infections since HIV/AIDS 1981 1982 1985 1987 1989 1994 1996 1997 1998 1999 2002 2005 2006 2009 2010 2011 2012 2012 2014 2016 2018 2020 2022 Human immunodeficiency virus (Worldwide) HEPICCOMMONInfection Lyme/borrelliosis identified (NE US) HUHCHS. Bovine spongiform encephalopathy (UK) Multidrug resistant tuberculosis (prisons in US and Russia) Herpesviruses are part of our Dengue 3, subtype III, virus (Sri Lanka) Variant Creutzfeldt-Jacob disease (UK) MAKeUP? Hendra virus (Australia) Reversion poliovirus vaccine virus (Dominican Republic) Influenza virus (Hong Kong) Enterovirus 71 fatal rhomboencephalitis (Asia) Nipah virus encephalitis (Malaysia and Singapore) West Nile virus encephalitis (New York) (resurgence in 2012) SARS (Asia and Canada) Herpes viruses are part of our virama. These are big Chickungunya virus (Indian Ocean basin) DNA viruses like the chickenpox, simplex virus EBV. They are part of our genetic makeup. St. Louis encephalitis (Argentina) Influenza A (H1N1) (Global) Cycloviruses Encephalitis/myelitis (Africa, SE Asia) Toscana virus (Mediterrean areas) 2011 Shiga toxin-producing E. coli (STEC) encephalopathy and seizures Exserohilum rostratum meningitis/stroke/abscess (methylpredisolone-assoc’d) Enterovirus D68 (Colorado, California) Zika virus (Brazil, China, Thailand, Columbia, Polynesia) Human pegivirus encephalitis (Canada, Poland Denmark, USA, South Africa) SARS-CoV-2/NeuroCOVID (global) Monkeypox virus (global) in Determinants of emerging infections IIMULOSUPPROSSOM ↑ - I susceptibility pUtSPreSSURO ON CHAMAIS TO MOVE. Susceptible populations: Poverty, war, famine, immunosuppression Disrupted environments: climate change and economic development Altered human and animal contact Chicken FarmS - - Take or more drugs Medical Practices immune suppre - Reservoirs Rapid and frequent global movement of animals and humans > Easy to transmit diseases. people live Longer due to medical TreatINTS. Avg. Life expec WF CahAdiaHhTale:82 Of - Power & Johnson, Neurologic Clinics 2009 Evolution of West Nile Virus => HAS VERY COMMONINGORIT TO NOrt America. - then other PlaCeSinAfriCatASia - usedas treatment for cancer +Encephalitis - very common when it first came to North America, has subsided now - first discovered in Africa, Uganda then elsewhere in africa and Asia - used as a treatment for cancer and results in encephalitis Some cases in France., Romania fiUSt COME Neurological infectious syndromes-a continuum Delineation of the clinical syndrome: ↑ NeCK • Meningitis: H/A, fever, nuchal rigidity + cranial meningitis Herpes simplex prototype. neuropathies. viral braintissue. this gets •GO Encephalitis: H/A, fever, confusion/altered behavior→coma, seizure, focal signs. • Myelitis: limb weakness, back pain, B&B disease spin dysfunction, sensory loss. • Abscess: focal signs, fever, seizure. FUNGUS Bacteria. • Radiculopathy/Neuropathy: localized radicular in PeripherGINS pain, fever, weakness. Infection Nerves in stiff is the into Herpes simplex 1 is the prototype all cord - - - H9V-2 STD -> - - - arms +legs. Crav+Pacterial infections. Neurological Infection Algorithm Infection Risks • Exposures • Prophylaxis • Season IGAST PRODICA• Co-morbidities Presentation • Syndrome •Acute vs. chronic meningitis? -ENCOPhalitis? - Localization? •Meninges •Brain •Spinal cord Physical Exam •Focal signs-LP? ? •Extra CNS features - -vaccinatedNOVAX. Neuroimaging •CT + PETSCOM •MRI Management •Supportive •Specific CSF Tests Blood Tests •CBC, electrolytes •Blood cultures - - - imaging Risk mortality of What is the long termOUtCOMeS. Serious RISKS - Directs to Prognosticate •Morbidity •Mortality - Brain Biopsy Locating the Lesions Humility Re-evaluation Lumbar spinal Tap.look spinal Fluid culture at cells look For viruses. - Neural cells To understand the pathology of the infections you need to understand the location of the infection • Central nervous system (CNS): neurons (+ axons), astrocytes, oligodendrocytes (+myelin), endothelial cells and microglia/macrophages-protected by the bloodbrain barrier. ↳ RealHaMiscelS • Peripheral nervous system (PNS): neurons (+ axons), Schwann cells, macrophagesprotected by the blood-nerve barrier. SCHIANCHISE A COMBINATION OF ASTOCAStOliGODEND # virusest cells cannot Blood brain barrier is unique as the viruses and cells cannot readily traverse. readilytraverse Blood-brain barrier I. TIGHTJUNCTION INITHMONY Mitochondria. 2. Support Cells A Expressionof cell adhesion molecules. of other - testes -> Have tightblood-tissueparrier MajOrPrOBIO HONTO get drugs across blood brain barrier. Ehrlich 1900 Astrocyte: the most abundant cell in the brain 1. -> Release cytokines? MOStabundant cell in the brain. TaIKS to all the cells -> 2. Fibroblast of the 3. brain. Neurologically active 4. susceptible to infections. 5. Critical For blood-brain Barrier - Oligodendrocytes: Huge nucleus - Loaded Nith eyes organ -highlymetabolically active. Perioxisomes -> Important targets for viruses. TFORPSULATION GROUND HerVeS. neuropathology-web.org Microglia: key players in brain inflammation - produce cytokines, - ehZYES, Free RadicalS - Normal Express MHC'S - Like MMPs, HSP proteases macrophages – immune derived ‘sensors’ SAC. Macrophages are typically IL-1, IL-6, TNF derivedfromDoheMarrow -> MICROGLIA from401K Activated – phagocytosis – chemotaxis – antigen presentation – cytotoxicity – morphological changes – proliferation – respiratory burst microglia IFN- T CELL IL-1 ROS (NO) MMPs EAAs TNF Neuronal death IL-1 IL-6 TNF Complement components MHC II, adhesion molecules. ASTROCYTE - Neurons You can generate other cell types easily CannotRegenerate NeurOnS. - - you can Regenerate interneurons protective properties ↓ susceptible to infections HerpeSSipleX - Electrically active, THANKING, - MOVEMENT. 10:1 RatiO In the human brain there are a billion neurons and 10x the size of astrocytes The neurovascular unit - ENCAPSUlateSall Cell TypeS SMOOTH p muscleType cell ↓ CrOSS-SECTION Of aXON IMYEAROUND Lanciotti et al., Int. J. Mol. Sci. 2022 Brain-blood interactions Interferon or macrophage. - T-Cell B-Cell COH Trafick into the Brain from blood scretechemokines, CYTOKINES. ↓ A 5 +rocy e + ACTIVATION ↓ Neurotropins the T and B cells are circulating in the blood. These cells can traffic into the brain - release cytokines and chemokines and induce neighboring cells such as astrocytes to release neurotrophins which can be protective towards neurons. the end goal of damaging a neuron is the damage of the oligodendrocytes which produce myelin for insulation. Walsh, Muruve, and Power 2014 Viral Neurotropism Neuron: HSV-1,-2, Rabies, West Nile, Nipah, Equine encephalitides, Mumps, VZV, Measles (SSPE), CMV - Oligodendrocyte: JCV, CMV They cause infectionof the neUrONS. measles can cause acute - encephalitisin children. - DelAXed RESPONSE. * Nocell in the brain is protected fromviral infections. Microglia, perivascular macrophages: Astrocyte: Equine encephalitis viruses, HIV, JCV, CMV, HTLV-1, ZIKA HIV, CMV Blood-brain barrier Endothelia: Noorbakhsh and Power 2006 Nipah virus, CMV Neurotropic retroviruses ~ Reteroviruses. 8% of your genome is comprisedof HuhaHendOgeHOUS ReterovirUSeS we have GNOREDICATION CAEV spumaviruses (HSRV) to express proteins. - INDICATED INMAURE VMV MuLV disease cancer. FIV lentiviruses EIAV HIV-1 Nhatis the Feline disease? D- type (SMRV) SIVagm HIV-2 primate but years! Has capacity accumulated over millionof competent non-primate - SIVmac B-type (HERV-K, MMTV) uselentivirus for gene - Delivery in people deficient incertain genes. ALV- like (RSV) HTLV-1/2 U5eReverse tranScriptaSCRNA> CDNA- PCR. - ----- the human retrovirus that causes neurologic disease which causes spinal cord disease in humans Power TINS, 2001 We use retroviruses as tools in the labs. We use lentivirus -HIV virus and use it forcauses gene delivery to treat people deficient in certain genes. We use reverse transcriptase to convert RNA - cDNA and do PCR. About 8% of your genome is comprised of retroviruses. We have accumulated these over millions of years these viruses are not replication competent but have the ability to express proteins implicated in cancer. the Disease P Sources of HIV-1 and -2 (Closer to SMV?) Lesvirulent ORIGINS Incentral Africa. - Democratic Republic of CONGO. HON did I spread throughout WOrId? HIV-1: Non-human primate to human xenoinfection Chimpanzee (Pan troglodytes) ➢ presumed source of HIV-1 • 38M people living with HIV today • 5 million new infections/yr worldwide Munters kill Chimps infected -> xit MIs HUNTERS GOT Infected IAOKPNG CHAPS. OreViUleN iN HUAHS. HIV is a chronic disease. It is a lentivirus and is a slow infection. In north America, it takes about 10 years to get AIDS after the primary infection ART emerged in 1996 and these drugs worked brilliant against HIV. When the ART first became available we started with treating people who were really sick, very high viral loads and very low CD4 counts. and had AIDS. But now with time we start early on like literally right away. HIV-1 Disease Course Infection Seroconversion Primary infection Asymptomatic CCR5 AIDS Treatment Phase CXCR4/CCR5 Antiretroviral • 37M people with HIV/AIDS globally. therapy (ART) • 18.7M receiving ART  • ~71K HIV+ people in Canada. • 25% of ART-treated persons with HIV have a neurological disorder. CD4 lymphocytes Viremia 4-8 weeks 10 years 1-4 years >10 years Power et al., CJNS 2009 IHIisChronic Disease -> centivirus SIONN infection +IH US It takeS 10 years to get NeuroHIV AIDS. Opportunistic Infections ART-assoc’d disorders (PML, TE, CMV-E/R CM, PCNSL) (NeuroIRIS, ATN, cART-NCI) Primary HIV Neurological Syndromes (HAND, DSP, VM, PM) DOF+Need TO KHOIalI The HIV Infection causes a lot of disease of the nervous system such as formation of microglial nodules and HIV gp41 inflammation and viral androgen in the brain, synctia like cells and T cells clustering together. HIV neuropathology in the ART era Microglial nodules Multinucleated giant cells (syncytia) HIV gp41 Perivascular cells Detection of HIV-1 RNA and DNA in HIV-infected brains by ddPCR - - TeStepeOpleNGO Have died from AIDS or Heredying Another group of people who come off anti-Reterovirals. - you can suppress the virus in Tissues. - blood, Reservoir Remains. Tepersistantvirus produces a range of Neurologic PNSCONS. - butcannot suppress fully in ⑤ people getting full Retroviral Syndromes, Therapy. Brain viral RNA, DNA, and integrated DNA were present in all HIV-infected persons and relatively unaffected by ART exposure despite suppression of plasma viral loads HIVASSOciated Neurodeg Syndrome. YOU getMORONIOSS, DECISION Mohammadzadeh et al., mBio 2021 MAKING, PSXCHAICSYAP STOOPCPARKASON Primary HIV-induced neurologic disorders Seroconversion Asymptomatic AIDS Peripheral Nervous System GBS/CIDP Mononeuritis Multiplex Previous slide: they looked at people who died of AIDS or other causes to study HIV and their response to therapy. 1. People who died of AIDS or other causes 2. people who were fully treated right to the time of death 3. people who just came of the antiretroviral therapy. you can suppress the virus in the blood to get the undetectable levels but you cannot suppress fully in the tissues. There is a reservoir that remains undealt with. DSP Myopathy Central Nervous System Acute & Chronic Meningitis/Seizures ANI → MND HAND → HAD Myelopathy Power et al, CJNS 2009 HIV-associated neurocognitive disorders Memory loss Alzheimer's Like symptoms Neuropsychiatric dysfunction Mania Immunodeficiency Motor abnormalities Parkinson's Disease HIV-induced brain atrophy in HAND The disease trajectory is variable, maybe it has to do with the strain of the virus or it is due to the host responses. The shrinkage of the brain reflects the loss of neurons -> shrinkage of the brain. trajectoryofthe disease is variable. The HAND progression Power et al, J Virol (1994) Neuroimaging and Clinical Case ▪ 38 y.o. bisexual HIV+ white male with 3-6 mo. history of: ➢increasing forgetfulness o ↓) InflammatiOn ➢slowed cognition and motor BrATM activity with poor concentration -DDISTUPTION blood brain ➢irritability, apathy barrier. ➢HDS score=6 proteinst viruses. ➢Gait ataxia, ↓ ➢tremor, hyperreflexia, BRAIN SHRINKAGE CATROPHY) ➢parkinsonian 6 ➢CD4=100, VL=10 1000 ↳ ▪ Responded to ART, returned to work 1 yr later Of ⑧ of - NOrMal -> *Machine learning identifies (anti-retroviral) host they looked at restriction factors that control the virus replication. This is the list of all the interferon related genes which are upregulated. Using machine learning they identified the gene that tend to contribute to HAND restriction factors in brain for group classification There are certain genes that confer suspectibility or protection against HAND - lookedat genes that to HAVE Happened MAN1B1 encodes ERManI HIV[+] vs. HIV[-] (Endoplasmic Reticulum Class I α-Mannosidase). Restriction factors. 0 25 50 75 ERManI is required for HIV-1 envelope glycoprotein degradation via ER-associated protein degradation pathway, assoc’d with TSPO. 100 HIV[+] vs. HAND MAN1B1 could be a potential biomarker for HAND/HIV neurovirulence. - genes that control virus. HIV[+] vs. HIV[-] - 0 - look atpost 25 50 75 70% Therearegenes that confer 100 List ofIFNRelatedgenes upregulated. - Using AItOfindHAND specific gene. Mohammadzadeh et al, Viruses 2023 Mohammadzadeh et al., in preparation to HAND. SUSCePtibility You get all the neurological symptoms because you loose the neurons which is confirmed by the MRI scan and chronic inflammation Unlike HERPES and rabies which infect the neurons, this virus infects microglial cells and perivascular macrophages AIDS-nondemented 1.0 Se NeurOnS MAP-2 2.CHRONIC IN GRATION HAND Whether it is cytokines that damage the neurons or in vitro viral proteins like the VPR protein and is combination of the both which ultimately leads to neuronal death or neural degeneration Chronic immune activation is the p53 p53 hallmark of HIV disease progression and HAND Power and Johnson, Adv Virus Res 2001 - unlike herpestRabies which infect neurons, the virus infects microglial cells. Both host and viral factors contribute to neurodegeneration and the eventual occurrence of HIV-associated neurocognitive disorders - Blood Whether its cytokines Brain neUrOHS.Or individual viral 3 combination proteins the envelope or * PVM damaging the Neuronal Death. VPR Protein Astrocyte Neurodegeneration. Host neuroinflammation TNF-/ IL-1β Macrophage IL-1β, TNF-, IFNα FIV/ HIV-1 Viral Factors Env, Vpr, Tat CD4 neurotrophins Neuron Neuronal Damage & Death CCR5 Microglia CXCR4 Neurodegeneration/HAND Lymphocyte BBB Mamik & Power 2017 Of BOTH JC (John Cunningham) virus and progressive multifocal leukoencephalopathy (PML) - Rare Neurologic Syndrome -DNA virus. - UbiquitOUS - INeCOM getall infectedas adUIS. - virus has specific Receptors - Transmitted orally • JC polyomavirus is a DNA virus and is ubiquitous in adult populations, yet PML is rare •30% of healthy people shed JC virus in urine •100% sewage samples are positive for JCV Pathway for JC virus entry into the brain DNA viruses are more stable -> after primaryinfection. Reorganization BacOReS ⑥archetype of virulent virus that is transmitted GIG brain Rearranges # Infects Oligodendrocytes + Astrocytes. Gene rearrangement in B cells virus has specific Receptors. JC virus genome undergoes rearrangement in progressive multifocal leukoencephalopathy (PML) The virus has specific receptors and hangs around the B cells. Not sure how it is transmitted but maybe orally. Unlike RNA viruses, DNA viruses are very stable. DNA viruses undergo reorganization after primary infection and become virulent. Once in the brain it infects oligodendrocytes and some astrocytes. Produces a range of neurological symptoms. Atkinson & Atwood, Viruses 2020 Typical presentation of PML •Progressive focal neurological deficits over days to weeks to months •Aphasia, apraxia and cerebellar signs •Mean survival: 6 months •Mortality in pre-cART era: ~100% MRI progression of PML - Infects the oligodendrocytes what partof the effects? brain does it Affects the white matter/subcortical brain matter? •Typically no enhancement or edema DoeSnO+ infects * the cortex whereneurons are. •Mottled or ground glass appearance •Spares the cortex Pathology of PML Myelin pallor/ Sparing of cortex Courtesy: Carlos Pardo, JHU GFAP JCV - Giant astrocytes JCV infection of astrocytes and oligodendrocytes Treatment of PML Indirect TreatmentOptionS - They are non-specific anti-retrovirus and using anti-retroviral therapy to boost their immune function. Antivirals: No proven effective antiviral treatment -> NoSpecific drug available. Restore immune function cART in HIV patients -D Transplant -> - eSeePRL in cancer patients. Stop ChenTOtherapy Patients. StOPPML -> IG MSDATIONS. -> Stop or reduce chemotherapeutic drugs in cancer and transplant patients Plasmapheresis of natalizumab in MS patients-controversial Immune enhancement drugs How can we enhance the immune system of patients. There are checkpoint inhibitor drugs used for cancer. Treating melanoma PD-1 they block those molecules -- boosts the immune system TheyStudy Rare Neurologic diseases like PML • Eight patients with PML received pembrolizumab. - These patients have profound immune suppression. • 2mg/kg; every 4-6 wks for 1-3 dosages using checkpointinhibitor drugs like -> cancer. • Five patients had clinical improvement/ stabilization of PML: reduction in lesion size on MRI, and decreased JC viral load. • Three showed no clinical benefit. New Approaches to treat PML • Immunotherapy – Checkpoint inhibitors PD-1, anti-PD-IBIOCK thOSOMOleCuleS – Cell based therapy DOOStinTKUne SYSteR * + Notarandomized controlTrial. -> -DSOME patientS diDNO SHONOHY benefit + some did • Anti-viral – Antisense oligonucleotides - Not a Randomized control trial. Human coronaviruses - Human Coronavirus Genus Genogroup HCoV-0C43 betacoronavirus 2A HCoV-229E alphacoronavirus 1B HCoV-HKU1 betacoronavirus 2A HCoV-NL63 SARS-CoV MERS-CoV alphacoronavirus betacoronavirus betacoronavirus 1B 2B 2C Has been arounda Receptor O-acetylated Sialic Acid (protein receptor unknown) APN O-acetylated Sialic Acid (protein receptor unknown) ACE2 ACE2 DPP4 long-time severalTotura and Bavari 2019 common coldare causedby Human Coronaviruses. - MERS Highly lethal in HUROHS. - Most of these viruses infect the brain and are associated with neurological disease SARS-COVOISOCOUSES Neurological diseases. COVID NEUROLOGICOI SYMPONS LOS SenSeOf smell taste, encephalopathy,strokes, seizures. DAM FOG. We have recognized these syndromes but we don't know underlying causes and mechanisms. Fatiguebrain FogC Parainfectious syndromes • Anosmia contribute to • Encephalopathy M00d Anxiety. • Stroke • Seizures • Meningitis/encephalitis Acute • Myositis • Peripheral neuropathy virus travels to brain ster ↓ anxiety dep + Acute Neurologica Neurological l Disorders Disorders ofinCOVID-19 COVID-199 - ReceptorS fOrSARSCOV.2 are concentratedin the Brain Sten. Post-viral syndromes • Acute disseminated encephalomyelitis • Acute necrotizing hemorrhagic encephalopathy • Limbic encephalopathy Toscano et al NEJM 2020, Zhao Lancet Neurol 2020 After acute COVID-19….the long haul “Long Covid” The virus likes to travel down to your brain stem where your level of awareness and a lot of neurotransmitters that contribute to mood. The receptors for SARS cov-2 are concentrated in the brain stem. We all thought that the virus was a hit and run situation but not anymore the virus persists 24 days post infection Science 2020 These symptoms resemble Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome. Distribution, quantification and replication of SARS-CoV-2 RNA across the human body assessed by ddPCR virus can stay A 24daXSpOS infection. Stein et al., Nature 2022 Mechanisms of neurological disorders in COVID-19 -> AUTOPGMUNY -> Antibodies, TCellS -> Neurovascular CONTributionSmallStrOKeS. - susceptible populations males obese, old age Adapted from Balcom et al., Ann Neurol 2021 Encephalitis in humans • viruses Encephalitis is defined by * areCOMON brain inflammation and is associated with multiple COUSC. infectious and non-infectious etiologies • The global prevalence of encephalitis outbreaks ranges between 3.5 and 7.5 per 100,000 • Flaviviruses (e.g., WNV, JEV, Dengue, ZIKV) are known to cause encephalitis in humans • ~50% of encephalitis cases have an unidentified etiologies. Unknown -52% Skulsujirapa et al., 2017 ↑ -> ONH55T patientsinncAhadaget diagnoses for encephalitsare WHO, 2006 Viral encephalitis incidence in Alberta Cumulative Incidence/100,000 tests for these haven't changed in 23 years. HSV-1 HSV-2 VZV EBV Increasing VZV incidence but 45.6% of encephalitis cases without a definitive diagnosis Bakal et al., submitte Clinical description of leukoencephalitis patients (LE-1 and -2) * Patient LE-1 LE-2 Age (yr) 51 61 Sex Female Female Clinical diagnosis Leukoencephalitis Leukoencephalitis February January Weight loss (22lb) Bilateral vision loss Memory loss Fatigue Ataxia Right knee effusion Central vertigo Horizontal diplopia Left facial droop Ataxia (mild) Month of disease onset Presenting symptoms and signs Past medical history Comorbidities T-cell lymphoma treated with allogenic bone marrow transplant (2001) Graves (early)/Hypothyroid (late) Urinary Tract infection (late) ↑ Idiopathic CRP elevation x 4 years Polyarthritis Lung adenocarcinoma (at autopsy) Hypothyroidism (late) * Absent fever, headache, peripheral leukocytosis and rash 1 MONTH -> seizures D TrOUBINGIKING Lumbar puncture. -> MRISCAM FLAIR - 12 MONTHs ①-> Whitematter changes --> brainster. Had underlying T1 (POST-GAD) -> BOTH immune suppression CONditiONS. 1. CanCer 2. T-COLYMPHOMG T2 Erin Balcom Balcom et al., Ann Neurol 2018 RNA Seq Analysis of brain - - - made cDNA library from RNA from the brain - did western Blots - the proteins of the brain were detectable MadeRNA Sea Library NesternBlotS Human pegivirus type-1 (HPgV-1) was detected in cortex and white matter from LE-1 and -2 brains but not in control brains. LE-1 CTX HPgV NS5A LE-1 WM LE-2 CTX LE-2 WM ODC WM -37kD Human Pegivirus (HPgV) -DDICTION VirUS at MSL REGION. -> the deleted virus froma patientin braindisease Replicated much higher is astrocytes microglial cells. • Formerly known as GB virus C (GBV-C) or hepatitis G virus (HGV) • Positive/single-strand RNA virus and a member of the flaviviridae family (e.g., Neurotropic -> WNV, JEV, ZIKV) Does not produce strong immune response and must be confirmed by PCR. * COMMON IN HIVinfected • Six human PgV genotypes identified to date • Prevalence is 1-5% in high income countries and 20% in LMICs • PgV genome previously detected in humans: Serum, Lymphoid tissue, Spleen, people. Kidney, Liver, Cerebrospinal Fluid and Brain (Kriesel et al., 2012). • Antibodies against the HPgV E2 protein are generated when clearing infection • Association with development of lymphoma/leukemia (Fama et al., 2018) • Potential transmission routes: vertical and horizontal routes WHAT DOES THIS MEAN??? ↑ HPgV-associated neuropathology CD8 CD8 CD8 CD8 • Infiltration CD8+ Tcells (e.g., CTLs) evident throughout the brain in LE-1. THERE WERE A LOT OF CTL'S IN BRAIN CD68 CD68 AP APP P • Abundant CD68+ macrophages in both LE-1 and LE-2. • Disrupted APP immunoreactivity in white matter of LE-1. Balcom et al., Ann Neurol 2018 Pegivirus detection LE-1 Brain (WM) LE-1 Brain (WM) LE-1 BM Biopsy (2001) LE-1 Brain Biopsy NS5A NS5A NS5A LE-2 Brainstem • Both the bone marrow (BM) and brain biopsies from LE-1 showed HPgV NS5A immunoreactivity. • HPgV immunopositive cells (resembling lymphocytes) were present in LE-1. • Immunopositive cells found in brainstem glial cells in LE-2 (inset) • Electron microscopy showed the presence of virus-like particles. HPgV clone with brain-derived NS2 deletion A When they sequenced the virus, they found a deletion in the virus NS2 region. ThisBwas not seen the WT virus but specific to brain derived virus. The virus with deleted NS2 region from patient with disease replicated higher than WT in astrocytes and microglial cells and did not really impact the neurons. 8969 414 E1 E2 NS2 NS3 NS4A NS4B NS5A NS5B ORF NS2 ΔNS2 C D Doan et al., Journal of Virology 2021 HPgV NS2 virus replicates more efficiently in astrocytes B 8×10 4 HPgV WT HPgV Copies/mL 7×10 4 HPgV NS2 6×10 4 5×10 4 4×10 4 * ** 3×10 4 *** 2×10 4 HPgV Copies/mL A 4×10 4 HPgV NS2 2×10 4 1×10 4 * 1×10 4 0 0 5 10 0 15 0 Time (days) Intracellular HPgV copies/g RNA 5000 **** *** 4000 3000 2000 * * 1000 0 HFM HFM HFM HFA HFA HFA Uninfected HPgV WT HPgV NS2 Uninfected HPgV WT HPgV NS2 D Intracellular HPgV copies/g RNA C HPgV WT 3×10 4 5 10 15 Time (days) 8000 * HPgV WT HPgV NS2 6000 4000 2000 0 0 2 4 6 8 Time (days) Matt Doan Doan et al., Journal of Virology 2021 Treatment for HPgV? -> anti Mepotherapysuppressedpeggyvirus expression iH 1100d. -> persistance using next gen technology + 108 A. B. 107 106 105 104 103 102 H -c tr l Pg V + +ct rl sa m pl es HPgV (NS5A) copies / mL Direct acting antiviral (DAA) therapy for HCV reduces HPgV viremia in HIV/HCV co-infected patients HPgV NS5A (and 5’ UTR) RNA quantitation by ddPCR in plasma (26% prevalence) Ledipasvir (LDV) & Velpatasvir (VEL) inhibit N5A Sofosbuvir (SOF) is a polymerase/NS5B inhibitor Telapravir (TEL) is a protease/NS3&NS4A inhibitor Hlavay et al., in preparation Hlavay et al., submitted with revisions Summary and Conclusions • Human Pegivirus (HPgV) brain infection causes fatal leukoencephalitis. • HPgV is a common infection with the potential for neuroadaptation and neurovirulence. • DAA might represent a therapeutic approach for treating HPgV infections Multiple sclerosis (MS) ▪ Multiple sclerosis or “many scars”: an inflammatory demyelinating disease of the CNS. · ▪ MS is characterized by progressive loss of vision, weakness, clumsiness, sensory changes or mental difficulties (memory loss, emotional instability) ▪ 3:1 predominance in women; age of onset:3-75 years; rising prevalence ▪ The cause of MS is unknown: ▪ Adaptive and innate immune factors ▪ Genetic susceptibility (MHC domain on chromosome 6) ▪ Infections (EBV, HHV6, HERVs, mycoplasma) ▪ Environment (Vitamin D, tobacco, latitude dependence) Multiple Sclerosis (MS) ▪ Initial pathology driven by myelin-reactive T-cells penetrating CNS Tloss of insulationaroundthe nerves. + B cells ▪ Lesions: regions of chronic local inflammation and neurodegeneration Tellactivationin the periphery ↓ Traffickintothe brain Inflammation ▪ ▪ ▪ ▪ Microglial activation some genetic susceptibility ROS/RNS Proinflammatory cytokines BBB breakdown - Demyelination ▪ ▪ ▪ ▪ Disruption in axonal conduction Metabolic stress Ion imbalances Axonal transection http://criticalhealthfacts.com/11-pictures-of-multiple-sclerosis-how-ms-affects-y Epstein Barr Virus (EBV) ●Association with MS known for many years ●Epidemiology: ubiquitous virus, >90% adults in North America ●Bjornevik et al., Science (2022): large longitudinal cohort of US military personnel (83% male) ○ 955 out of 10 million developed MS; 801 serum samples studied ■ Only 1 patient tested negative for EBV prior to MS onset (>97%) ■ Only 57% of patients who did not develop MS had + serology for EBV (IgG) ■ EBV seropositivity increased risk of developing MS 32-fold EBV- timing of exposure (Thacker et al., 2006, Annals of Neurol) Herpesvirus papio (HVP)-lymphocryptovirus in NHPs (EBVlike herpes virus) Haanstra et al., PLoS One, 2013 Murine gammaherpes virus-68 (MHV-68; murine EBV-like virus) combined with EAE -> This virus extenuates auto-immune disease in mice. Casiraghi et al, 2012 Is EBV present in the brain of MS patients? & ● Increased EBV IgG in CSF of MS patients compared to controls (Ruprecht et al., J Neurol 2018) ○ Lower than seen with other pathogens ○ Lower compared to presence of antiEBV IgG in serum ● Several PCR studies in serum and CSF generally no difference between MS and controls (Linsey et al., 2009, Multiple Sclerosis) ● In situ hybridization: some studies show EBV proteins and DNA at greater frequency in MS lesions than non-MS patients — results have not been replicated How might EBV contribute to MS? DIgMRESPONSE,IgG - ?Reverse causation: preclinical immune dysregulation increases risk of EBV – limited evidence ?Immortalization of autoreactive B-cells ?Persistent infection → inflammation and neurodegeneration ?Molecular mimicry: EBV antigens may lead to production of cross-reactive antibodies and lymphocytes Robinson and Steinman, 2022, Science