Metabolism, Infection and Immunity in Mitochondrial Disease Peter J. McGuire MS, MD Head, MINI Section National Human Genome Research Institute 5 October 2018
No conflicts of interest to declare
Outline • What is the immune system and why is it important? • Infection and mitochondrial disease • Immune function in mitochondrial disease
Why is the immune system important? • Protects us against Fungi Bacteria Viruses Pollution Parasites Cancer
The immune system has multiple lines of defense
The immune system is composed of organs and cells Organs Cells
The immune system has many different type of cells Bone graft Macrophage Mast cell Eosinophil Erythrocytes Marrow Basophil Monocyte Megakaryocyte Bone Hematopoietic stem cell Multipotential Myeloid stem cell progenitor Neutrophil cell Platelets Lymphoid progenitor cell Dendritic cell T lymphocyte B lymphocyte Natural killer cell
How does the immune system protect us? • Body learns to defend itself by: – Natural infection – Vaccination
How does the immune system protect us?
How does the immune system protect us?
Why study the immune system immune and mitochondrial disease (MD)? • Because: – Infection is bad for patients with mitochondrial disease • Our questions: – What happens to patients with MD during infection? – Does having MD affect immune function?
Infection is bad for patients with MD • Point #1: Infection increases energy requirements – For every 1 � C of fever, metabolic rate can increase 10% or more – Problem: need more calories, but you don’t feel like eating; ê ability to generate energy
Infection is bad for patients with MD • Point #2: Infection can lead to an increase in tissue lactate production Tarasenko et al (submitted)
Infection is bad for patients with MD • Point #3: Immune reactions can damage mitochondria 1.5 * Complex I + III / CS 1.0 0.5 0.0 Control Poly I:C Tarasenko et al (submitted)
Infection is bad for patients with MD • Point #3: Immune reactions can damage mitochondria 20 1.5 * Serum mtDNA Hepatic mtDNA (control ratio) (control ratio) 15 1.0 10 0.5 5 0 0.0 d 8 d 8 e R R e f P f P - - r r i i a a P P Tarasenko et al (submitted)
Infection is bad for patients with MD • Point #4: The immune response may be part of the problem - cytokines Basal Maximal * 200 200 * OCR (pmoles/min) OCR (pmoles/min) Immune cells “text” 150 150 each other by cytokines 100 100 May be innocent 50 50 bystanders (e.g. liver) 0 0 Control TNF α Control TNF α cytokines Cytokines produced as part of the immune response inhibit mitochondrial metabolism in human liver cells.
Infection is bad for patients with MD • Point #5: What do we see clinically with infection? 100 Encephalopathy Ataxia Neurologic events (%) 43% Acidosis SLE 50 0 Edmonds et al. (2002)
The need for translational research in MD Metabolic decompensation • In extremis (life- threatening) - Bioenergetic failure - Lactic acidosis - Organ failure (e.g. liver failure) - Encephalopathy - Stroke - Sequelae • Extensive ICU care • Viral infections Clinical question: How did we arrive at this point? • Treatment is inadequate 1) Are patients with MD immunodeficient? 2) What is the role of inflammation in MD pathophysiology?
Immune function in MD • Since infection can be very serious... – How well does the immune system function in patients with MD?
• mtDNA depletion syndrome • ê Complex II+III and IV in muscle • Recurrent infections, RIP 18 months with septicemia • Hypogammaglobulinemia by 15 months • ê Memory T-cells, CD8+ T-cells, NK cells • ê T-cell response to Il-2
Immune function and MD • What do we know? Not much, but… – Immune cells don’t like high levels of toxins – Mitochondrial RC deficiencies can also be present in immune organs and cells
Immune function and MD: toxins (lactate)
Mitochondrial dysfunction in immune cells It all started with a clinical case… 1.5 • 15 year old male Complex III / CS • Complex III deficiency (control ratio) • Multisystem disease 1.0 – Neurologic – Musculoskeletal 0.5 – Endocrine – Immunologic • Multiple infections 0.0 Controls Patient • Hypogammaglobulinemia • Loss of pneumococcal titers • Research exome pending McGuire et al. (unpublished data)
Clinical features of MD • Multisystem • é energy organs • mtDNA and nDNA inheritance • Most common IEM • Lactic acidosis • Complications during/after decompensation (Edmonds et al, 2002) • Pathophysiology: energy deficiency, ROS Immune system
Recurrent infection is common in patients with MD Tarasenko et al, Cell Metab, 2017
Immunodeficiency screen for MD patients % positive 4+ OM/yr 100 2+ sinus inf/yr 20 40 60 80 0 2+mo Abx 2+ PNA/yr FTT/GF IV Abx Need ICU Admit Recovery Deep Abscess Fungal Inf 2+Inf/Sepsis FHx 1 o ID Pt Hx ID Immuno Eval IVIG Abx PPx
Patients with MD may have poor immune memory CD45RA +& CD45RO /& Naïve& CD45RA /& CD45RO +& Memory& (protective)
Vaccination Rate Vaccination rates MMR Vaccination rates VAR 8% 16% 84% 92% YES INCOMPLETE Kruk et al (unpublished data)
MMR seropositivity Measles seropositivity % 100 Measles cases per year Year Cases 80 2010 63 2011 220 60 2012 55 2013 187 40 2014 667 2015 188 20 2016 86 2017 118 0 2018 63 l D o M r t n o C Kruk et al (unpublished data)
Varicella seropositivity Varicella seropositivity % 100 80 60 40 20 0 Control MD Kruk et al (unpublished data)
How does the immune system protect us?
Hypothesis: Bioenergetic deficiency in MD may extend to immune cells leading to immunodeficiency. Tarasenko et al, Cell Metab, 2017
How many patients have problems with infection? How many patients are on IVIg?
The mystery of IVIg IVIg •intravenous immune globulin •aka “antibodies” •produced from human plasma •Immune mediated conditions •Immunodeficiency •Other effects? Benefits? •Does the pathology of MD have an immune component?
Hypothesis: Bioenergetic deficiency in MD may extend to immune cells leading to immunodeficiency. Fever 10 8.0 Lactate Lactate (mmol/L) pH 8 7.5 6 pH • 8 y/o male with MD 4 7.0 2 • Received PICC line 2 0 6.5 weeks prior for access m ) WBC (cells x 10 3 /mm 3 ) • Presented with fever and 8 WBC hospitalized 6 4 2 0 1 2 3 4 5 6 y y y y y y a a a a a a D D D D D D
Hypothesis: Bioenergetic deficiency in MD may extend to immune cells leading to immunodeficiency. 1000 • 8 y/o male with MD 900 • Received PICC line 2 IgG (mg/dL) weeks prior for access 800 • Presented with fever and 700 hospitalized 600 500 Day 1 Day 2 Day 3
Translational model: TCox10 -/- COX10 • Maturation of cytochrome C oxidase (CIV) • Present in lymphocytes • Deficiency: MD or Leigh phenotype • KO in T-cells only X" • Mice are generally healthy CD4&Cre" Cox10 flox/flox" TCox10 &/&" Tarasenko et al, Cell Metab, 2017
Compromised respiratory chain in TCox10 -/- T-cells 2000 **** 1500 COX / CS 1000 500 0 WT TCox10 -/- **** 500 OCR (pmoles/min) 400 300 200 100 0 T W - / - 0 1 x o C T Tarasenko et al, Cell Metab, 2017
TCox10 -/- peripheral lymphocyte counts Baseline 15 10 90 Lymphocytes (K/ µ L) Lymphocytes % 80 8 WBC (K/ µ L) 10 70 6 60 4 5 50 2 40 0 0 30 T - T - T 0 -/- / / - - W W W 0 0 HEMAVET 1 1 1 TCox10 x TCox10 x TCox10 x o o o C C C T T T Infection Infection 0 6.5 15 90 / L) s % 10 WBC (cells x 10 3 /mm 3 ) Lymphocytes (K/ µ L) 8 Lymphocytes % / L) 80 * *** WBC (K/ µ L) * 8 *** WBC 6 10 70 6 4 60 4 5 50 2 40 2 0 0 30 0 1 2 3 3 4 5 6 y y y y y y y WT - -/- WT / - WT TCox10 -/- a a a a a a a TCox10 D D D D D D D TCox10 Tarasenko et al, Cell Metab, 2017
How does the immune system protect us?
Vaccination response is impaired in TCox -/- Y Y Y Y Y Y Y Y Y Y Y Y Y Y 2 � 1 � 0 14 28 35 Days 2 weeks (1 � ) 5 weeks (2 � ) **** 2.0 2.0 IgG1 (control ratio) IgG1 (control ratio) **** 1.5 1.5 1.0 1.0 0.5 0.5 * 0.0 0.0 TCox10 -/- WT Blank TCox10 -/- WT Blank • Clinical correlate: loss of vaccine titers Tarasenko et al, Cell Metab, 2017
How does the immune system protect us?
Influenza viral clearance is impaired in TCox10 -/- 150 (control ratio) NP mRNA 100 50 0 TCox10 -/- WT Tarasenko et al, Cell Metab, 2017
Summary • The immune system is important for vaccination and protection against infection • Infection may be detrimental to patients with MD • Subsets of patients with MD may have immune dysfunction – Toxicity – Metabolic dysfunction
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