REAWAKENING RETROCYCLINS: ANCESTRAL HUMAN DEFENSINS ACTIVE AGAINST HIV-1. (REPORT).
This study by researchers at the University of Massachusetts showed that MatTek’s EpiVaginal in vitro 3-D human cervico-vaginal tissue equivalent can be used to demonstrate the ability to restore endogenous expression of retrocyclin peptides. Human alpha and beta defensins contribute substantially to innate immune defenses against microbial and viral infections. Certain nonhuman primates also produce theta-defensins — 18 residue cyclic peptides that act as HIV-1 entry inhibitors. Multiple human theta-defensin genes exist, but they harbor a premature termination codon that blocks translation. Consequently, the theta-defensins (retro-cyclins) encoded within the human genome are not expressed as peptides. In vivo production of theta-defensins in rhesus macaques involves the post-translational ligation of two nonapeptides, each derived from a 12-residue “demidefensin” precursor. Neither the mechanism of this unique process nor its existence in human cells is known. To ascertain if human cells retained the ability to process demi-defensins, we transfected human promyelocytic cells with plasmids containing repaired retrocyclin-like genes. The expected peptides were isolated, their sequences were verified by mass spectrometric analyses, and their anti-HIV-1 activity was confirmed in vitro. This study reveals for the first time, to the researchers knowledge, that human cells have the ability to make cyclic theta-defensins. Given this evidence that human cells could make theta-defensins, we attempted to restore endogenous expression of retrocyclin peptides. Since human theta-defensin genes are transcribed, we used aminoglycosides to read-through the premature termination codon found in the mRNA transcripts. This treatment induced the production of intact, bioactive retrocyclin-1 peptide by human epithelial cells and cervicovaginal (EpiVaginal) tissues. The ability to reawaken retrocyclin genes from their 7 million years of slumber using aminoglycosides could provide a novel way to secure enhanced resistance to HIV-1 infection.
Air-liquid interface, Aminoglycosides, Cervicovaginal tissues, Defensins, EpiVaginal, HIV-1, Immuno-dotblot analysis, Innate immunity, Lamina propia, Langerhans cells, Retrocyclin-1 peptide, Retrocyclins, Theta-defensins, Theta-defensins (retrocyclins)
Aminoglycosides, Anti-retrocyclin antibody, HIV-1, Human defensins, Tobramycin
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RETROCYCLINES: Anchestrine ya kinga ya binadamu inayofanya kazi dhidi ya HIV-1 (REPORT). Mattek's EpiVaginal in vitro 3D human cervical-vaginal tissue equivalent inaweza kutumika kuonyesha uwezo wa kurejesha endogenous expression ya retrocyclin peptides. Alpha na beta defensins za binadamu huchangia sana ulinzi wa kinga ya asili dhidi ya maambukizo ya vimelea na virusi. Vipuli vingine vinavyoitwa theta-defensins na 18 residual cyclic peptides vinavyofanya kazi kama kizuizi cha kuingia kwa virusi vya HIV. Kuna chembe nyingi za urithi za theta-defensin za binadamu, lakini zina kodoni ya kukomesha mapema ambayo huzuia tafsiri. Kwa hiyo, theta-defensins (retro-cyclins) zilizoandikwa ndani ya genome ya binadamu hazionyeshwi kama peptides. In vivo uzalishaji wa theta-defensins katika rhesus macaques inahusisha baada ya tafsiri ligation ya nonapeptides mbili, kila mmoja inayotokana na 12-residual <unk> demidefensin <unk> mtangulizi. Utaratibu wa utaratibu huo wa pekee wala kuwepo kwake katika chembe za binadamu haujulikani. Ili kujua kama chembe za binadamu zilihifadhi uwezo wa kusindika demi-defensins, tulibadilisha chembe za binadamu za promyelocytic na plasmids zenye jeni zilizorekebishwa kama retrocyclin. Peptides zilizotarajiwa zilitengwa, mfululizo wao ulithibitishwa na uchambuzi wa spectrometric ya wingi, na shughuli yao ya kupambana na HIV-1 ilithibitishwa in vitro. Utafiti huu unaonyesha kwa mara ya kwanza, kwa ujuzi wa watafiti, kwamba seli za binadamu zina uwezo wa kutengeneza theta-defensins za mzunguko. Kwa kuzingatia ushahidi huu kwamba chembe za binadamu zinaweza kutengeneza theta-defensins, tulijaribu kurejesha usemi wa ndani wa peptides za retrocyclin. Kwa kuwa chembe za urithi za theta-defensin za binadamu huandikwa, tulitumia aminoglycosides kusoma-kupitia codon ya kumaliza mapema iliyopatikana katika maandishi ya mRNA. Matibabu haya yalisababisha uzalishaji wa peptidi ya retrocyclin-1 isiyoharibiwa, yenye bioactive na seli za epithelial za binadamu na tishu za cervicovaginal (EpiVaginal). Uwezo wa kuamsha jeni za retrocyclin kutoka kwa usingizi wa miaka milioni 7 kwa kutumia aminoglycosides inaweza kutoa njia mpya ya kupata upinzani wa kuongezeka kwa maambukizi ya HIV-1. Vipimo vya Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa wa Ugonjwa.