Modulating the Immune System to Combat Bacterial Infection Birgitta Agerberth Karolinska Institutet Sweden
Our Concept To induce the production of endogenous antimicrobial peptides through small molecules that can be taken orally. To be used together with standard antibiotic treatment. Can we clear infections faster? Can we decrease antibiotic consumption?
Production and activity of antimicrobial peptides Broad spectrum microbicidal activity Produced by epithelial and circulating immune cells Positively charged Amphipathic Zasloff M, Nature, 2002
Antimicrobial peptides are multifunctional Lai & Gallo, Trends Immunol., 2009
Main gene families of antimicrobial peptides in mammals Cathelicidins and Defensins LL-37 (neutrophil, monocyte/macrophage, epithelial cells) Promoter Exon 1 Exon 2 Exon 3 Exon 4 CAMP gene Signal peptide (~30 aa) Pro LL-37/hCAP-18 Cathelin domain (99-114 aa) Mature peptide (12-100 aa) LL-37
Downregulation of LL-37 in shigellosis Normal Shigella infected Islam et al., Nature Med, 2001.
Butyrate counteracts the downregulation of cathelicidin in rabbits Healthy Infected Infected Butyrate Raqib et al., PNAS, 2006
Mycobacterium tuberculosis downregulates LL-37 in human macrophages 1,2 LL-37 mrna expression (fold induction) 1,0 0,8 0,6 0,4 0,2 *** Human MDMs THP-1 cells ### Pro LL-37/hCAP-18 17k Da 0,0 Unstimulated Infected (H37Rv) LL-37 6k Da Rekha et al., Autophagy, 2015
Phenylbutyrate and Vitamin D counteract the downregulation LL-37 mrna expression (fold induction) 600 Human MDMs 500 THP-1 cells 400 300 200 15 10 5 ### *** 0 Control Infected (H37Rv) Inf+2 mm PBA ** * # *** ### ## Inf+10 nm 1,25-(OH) 2 D 3 Inf+2 mm PBA+10 nm 1,25-(OH) 2 D 3 17 kda 14 kda 6 kda GAPDH Rekha et al., Autophagy, 2015
Phenylbutyrate and Vitamin D inhibit Mtb growth in human macrophages Rekha et al., Autophagy,2015
Clinical trial of newly diagnosed TB patients Aim To evaluate the potential role of PBA and Vitamin D 3 as adjunctive therapy for 2 months in pulmonary tuberculosis
Study design A double blind placebo-controlled randomized clinical trial Pulmonary TB patients (n=288) 500 mg PBA twice daily (n=72) 500 mg PBA twice daily+ 5000 IU VitD3 (n=72) 5000 IU VitD3 (n=72) Placebo (n=72)
Outcomes Primary outcomes: Proportion of TB patients becoming sputum culture negative at week 4 Clinical recovery at week 8 Secondary outcomes: LL-37 level in macrophages and lymphocytes Sputum smear conversion time radiological improvement cough clearance weight gain 25-hydroxyvitamin D 3 concentration ex vivo killing of Mtb by macrophages
Sputum culture negative at week 4 71% in PBA + vitd 3 61.3% in vitd 3 42.2% in placebo Mily et al., PLOS One, 2015
Clinical scores Clinical recovery was assessed by using scores for the following: Clinical features Assigned scores Cough 1 Haemoptytis 1 Chest pain 1 Dyspnea/ shortness of breath 1 Anorexia 1 Anemia 1 Fever ( 37.8 C) 1 Chest x-ray 3 Others 0.5 Total scores 10.5
Decline of Clinical scores with time Scores declined significantly in the groups of PBA and PBA+VitD 3 Mily et al., PLOS One, 2015
Autophagy
PBA and Vitamin D induce the expression of autophagy protein LC3-II Rekha et al., Autophagy, 2015
PBA and Vitamin D induce the expression of autophagy related gene Beclin-1 and Atg5 Rekha et al., Autophagy, 2015
Induction of autophagy by PBA and Vitamin D is mediated by LL-37 LL-37 shrna THP-1 cells NS shrna THP-1 cells Rekha et al., Autophagy, 2015
Induction of autophagy by LL-37 is mediated by P2X7 receptor Rekha et al., Autophagy, 2015
Main findings Phenylbutyrate induces autophagy in human macrophages via LL-37 Induction of autophagy by LL-37 is mediated by P2X7 receptor Affects Mtb survival in macrophages Phenylbutyrate also exhibits direct bacteriostatic effect to Mycobacterium tuberculosis Coussens et al., PLOS Pathogens, July 2015
Generation of a reporter cell line Vector construct transfected into the colonic epithelial cell line HT-29 Integrates into the genome and several clones are generated One clone was chosen as a cell model to develop a 96-well reporter assay for LL-37 induction Nylén et al., Innate Immun, 2013
Fold induction 14 12 Screening of HDAC inhibitors 10 8 6 4 2 0 Entinostat is in phase I and II in clinical trials: toxicity and pharmacology are known Nylén et al., Innate Immun, 2013
Inducers of antimicrobial peptide expression Vitamin D 3 Lactose Lithocholic acid Phenylbutyrate Sodium Butyrate Entinostat
Acknowledgement Peter Bergman, LabMed, KI, Huddinge Gudmundur H Gudmundsson, Univ. of Iceland Rubhana Raqib, icddr,b, Bangladesh Susanna Brigenti, CIM, KI, Huddinge Roger Strömberg, BioNut, KI, Huddinge Rokeya S. Rekha, LabMed, KI, Huddinge Frank Nylén, LabMed, KI, Huddinge Protim Sarker, icddr,b, Bangladesh Akhirunnesa Mily, icddr,b, Bangladesh Jagadeeswara R Muvva, CIM, KI, Huddinge Chris Moore, LabMed, KI, Huddinge Erica Miraglia, LabMed, KI, Huddinge Min Wan, MBB, KI
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