title: Oral intake of phenylbutyrate with or without vitamin D3 upregulates the cathelicidin LL-37 in human macrophages: a dose finding study for treatment of tuberculosis.
abstract: BACKGROUND
  We earlier showed that 4-phenylbutyrate (PB) can induce cathelicidin LL-37 expression synergistically with 1,25-dihydroxyvitamin D3 in a lung epithelial cell line. We aimed to evaluate a therapeutic dose of PB alone or in combination with vitamin D3 for induction of LL-37 expression in immune cells and enhancement of antimycobacterial activity in monocyte-derived macrophages (MDM).
  
  
  METHODS
  Healthy volunteers were enrolled in an 8-days open trial with three doses of PB [250 mg (Group-I), 500 mg (Group-II) or 1000 mg (Group-III)] twice daily (b.d.) together with vitamin D3 {5000 IU once daily (o.d.)}, PB (500 mg b.d.) (Group-IV) or vitamin D3 (5000 IU o.d.) (Group-V), given orally for 4 days. Blood was collected on day-0, day-4 and day-8; plasma was separated, peripheral blood mononuclear cells (PBMC), non-adherent lymphocytes (NAL) and MDM were cultured. LL-37 transcript in cells and peptide concentrations in supernatant were determined by qPCR and ELISA, respectively. In plasma, 25-hydorxyvitamin D3 levels were determined by ELISA. MDM-mediated killing of Mycobacterium tuberculosis (Mtb) (H37Rv) was performed by conventional culture method.
  
  
  RESULTS
  MDM from Group-II had increased concentration of LL-37 peptide and transcript at day-4, while Group-I showed increased transcript at day-4 and day-8 compared to day-0 (p < 0.05). Both Group-I and -II exhibited higher levels of transcript on day-4 compared to Group-III and Group-V (p < 0.035). Increased induction of peptide was observed in lymphocytes from Group-II on day-4 compared to Group-I and Group-IV (p < 0.05), while Group-IV showed increased levels on day-8 compared to Group-I and Group-III (p < 0.04). Intracellular killing of Mtb on day-4 was significantly increased compared to day-0 in Group-I, -II and -V (p < 0.05).
  
  
  CONCLUSIONS
  The results demonstrate that 500 mg b.d. PB with 5000 IU o.d. vitamin D3 is the optimal dose for the induction of LL-37 in macrophages and lymphocytes and intracellular killing of Mtb by macrophages. Hence, this dose has potential application in the treatment of TB and is now being used in a clinical trial of adults with active pulmonary TB (NCT01580007).
authors.affiliation: International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Mohakhali, Dhaka 1212, Bangladesh.
authors.forename: Akhirunnesa
authors.initials: A
authors.lastname: Mily
authors.forename: Rokeya Sultana
authors.initials: RS
authors.lastname: Rekha
authors.forename: S M Mostafa
authors.initials: SM
authors.lastname: Kamal
authors.forename: Evana
authors.initials: E
authors.lastname: Akhtar
authors.forename: Protim
authors.initials: P
authors.lastname: Sarker
authors.forename: Zeaur
authors.initials: Z
authors.lastname: Rahim
authors.forename: Gudmundur H
authors.initials: GH
authors.lastname: Gudmundsson
authors.forename: Birgitta
authors.initials: B
authors.lastname: Agerberth
authors.forename: Rubhana
authors.initials: R
authors.lastname: Raqib
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000008:administration & dosage; D002118:Calcium / Q000097:blood; D002478:Cells, Cultured; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D010654:Phenylbutyrates / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000378:metabolism; D014376:Tuberculosis / Q000188:drug therapy*; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood; D055815:Young Adult; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D000970:Antineoplastic Agents; D010654:Phenylbutyrates; D012333:RNA, Messenger; D014815:Vitamins; D002762:Cholecalciferol; C075773:4-phenylbutyric acid; D002118:Calcium; D054804:Cathelicidins