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1.
J Eur Acad Dermatol Venereol ; 33(11): 2168-2178, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31304993

ABSTRACT

BACKGROUND: Few clinical trials have evaluated long-term treatment of nail psoriasis with biologics. OBJECTIVE: Safety and efficacy of adalimumab [ADA; Humira AbbVie Inc, North Chicago, IL, USA)] long-term treatment (52 weeks) was evaluated in a phase-3, randomized trial in patients with moderate-to-severe plaque psoriasis and concomitant moderate-to-severe fingernail psoriasis. Results from the first 26 weeks (Period A) have been reported. METHODS: Patients receiving 40 mg ADA every other week or placebo in Period A, continued with or switched to 40 mg ADA every-other-week treatment in the subsequent 26-week open-label extension (OLE) period. Main efficacy evaluations were ≥75% improvement in total-fingernail modified Nail Psoriasis Severity Index (mNAPSI 75) and achievement of Physician's Global Assessment for Fingernail Psoriasis of clear or minimal disease (PGA-F 0/1) with a ≥2-grade improvement from baseline, across the trial for patients who continued ADA from Period A through the OLE (Continuous-ADA Population). Safety was evaluated during the OLE and for patients receiving ADA at any time during the study (All-ADA Population). RESULTS: Of the 217 patients initially randomized in Period A, 188 (86.6%; 94 in each treatment group) entered the OLE after completion of or early escape from Period A. For the Continuous-ADA Population (N = 109), endpoint achievement rates improved from OLE entry (Week 26) to Week 52, including total-fingernail mNAPSI 75 (47.4-54.5%); PGA-F 0/1 (51.1-55.6%) and total-fingernail mNAPSI = 0 (6.6-17.9%). Serious adverse event and serious infection rates for the All-ADA Population (N = 203) were 6.9% and 3.4%, respectively. CONCLUSIONS: In this population of psoriasis patients with concomitant, moderate-to-severe nail psoriasis, long-term efficacy and improvement in signs and symptoms of nail disease were demonstrated after every-other-week ADA treatment, including incremental improvements in rate of total clearance of nail disease. No new safety risks were identified for patients receiving at least one ADA dose across 52 weeks.


Subject(s)
Adalimumab/therapeutic use , Nail Diseases/drug therapy , Psoriasis/drug therapy , Adalimumab/adverse effects , Adult , Double-Blind Method , Female , Humans , Male , Middle Aged , Nail Diseases/complications , Psoriasis/complications , Severity of Illness Index , Time Factors , Treatment Outcome
2.
Br J Dermatol ; 181(5): 967-975, 2019 11.
Article in English | MEDLINE | ID: mdl-30916379

ABSTRACT

BACKGROUND: Weekly adalimumab (Humira® ) is approved for the treatment of hidradenitis suppurativa (HS) based on the 12-week placebo-controlled periods of the two phase III PIONEER trials. OBJECTIVES: Using PIONEER integrated trial results, we aimed to evaluate the optimal medium-term adalimumab maintenance dosing strategy for moderate-to-severe HS. METHODS: Each trial had two double-blind periods; 12-week Period A and 24-week Period B. Patients randomized to adalimumab 40 mg every week (ADAew) (Period A), were rerandomized in Period B to ADAew (ADAew/ew), ADA every other week (ADAew/eow), or placebo (ADAew/pbo). Placebo-randomized patients were reassigned in Period B to ADAew (PIONEER I) or placebo (PIONEER II). The primary outcome was HS Clinical Response (HiSCR). Patients who lost response during Period B were discontinued from the study and offered an option to enter the open-label extension (OLE) to receive ADAew. Results are reported across the two study periods, and data were combined from the two study periods and the OLE. RESULTS: For week-12 HiSCR achievers, the HiSCR week-36 rate was 48·1% (ADAew/ew) vs. 46·2% (ADAew/eow) and 32·1% (ADAew/pbo). Combining (post hoc) these patients with week-12 partial responders further differentiated outcomes in Period B (ADAew/ew 55·7% vs. ADAew/eow 40·0% and ADAew/pbo 30·1%). Period-B adverse-event rates were ADAew/ew 59·6% vs. ADAew/eow 57·4% and ADAew/pbo 65·0%. One patient (ADAew/ew) reported a serious infection. CONCLUSIONS: Weekly adalimumab treatment, effective throughout 36 weeks, was the optimal maintenance medium-term dosing regimen for this population. At least partial response after 12 weeks with continued weekly dosing had better outcomes than dose reduction or interruption. Patients who do not show at least a partial response to weekly adalimumab by week 12 are unlikely to benefit from continued therapy. No new safety risks were identified. What's already known about this topic? Hidradenitis suppurativa (HS) is a chronic inflammatory disease, commonly misinterpreted as an infection and treated with long-term antibiotic regimens or surgical incisions. Based on the chronicity of HS and the lack of evidence for efficacious and safe long-term HS treatments, it is important to evaluate medium- to long-term therapies for HS. Weekly adalimumab (Humira® ) is approved for the treatment of moderate-to-severe HS based on the two phase III PIONEER trials. What does this study add? This study pooled data from the two PIONEER trials, providing a more robust assessment of outcomes. After at least partial treatment success with weekly adalimumab short-term therapy (12 weeks), continuing weekly dosing during the subsequent 24 weeks had better outcomes than dose reduction or treatment interruption. Patients who do not show at least a partial response to weekly adalimumab by week 12 are unlikely to benefit from continued therapy.


Subject(s)
Adalimumab/administration & dosage , Hidradenitis Suppurativa/drug therapy , Maintenance Chemotherapy/methods , Tumor Necrosis Factor Inhibitors/administration & dosage , Adalimumab/adverse effects , Adolescent , Adult , Aged , Double-Blind Method , Drug Administration Schedule , Female , Hidradenitis Suppurativa/diagnosis , Humans , Intention to Treat Analysis , Male , Middle Aged , Placebos/administration & dosage , Placebos/adverse effects , Severity of Illness Index , Time Factors , Treatment Outcome , Tumor Necrosis Factor Inhibitors/adverse effects , Young Adult
3.
J Eur Acad Dermatol Venereol ; 31(1): 89-95, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27504914

ABSTRACT

BACKGROUND: This phase 3 trial is the first to evaluate the efficacy and safety of treatment with the systemic TNF-α inhibitor, adalimumab, for Chinese patients with moderate-to-severe plaque psoriasis. METHODS: In the 12-week, double-blind, placebo-controlled Period A, patients were randomized 4 : 1 to receive adalimumab 40 mg every-other-week (following a single 80 mg dose), or placebo every-other-week. In the subsequent 12-week, open-label, Period B, all patients received adalimumab 40 mg every-other-week starting at week 13, following a single, blinded dose at week 12 of adalimumab 80 mg or matching placebo (for patients receiving placebo or adalimumab in Period A respectively). In Period A, efficacy was analysed for all randomized patients and safety for all patients receiving ≥1 dose of the study drug. RESULTS: For the 425 patients in this study (87 placebo; 338 adalimumab), a higher percentage randomized to adalimumab achieved the primary endpoint of ≥75% improvement from baseline in PASI score (PASI 75) at week 12: placebo 11.5% (10/87); adalimumab 77.8% (263/338; P < 0.001). Physician's Global Assessment of clear to minimal was achieved at week 12 by 14.9% placebo (13/87) and 80.5% adalimumab (272/338; P < 0.001). For patients who received adalimumab at any time during the study (All-adalimumab Population), treatment-emergent adverse events (AEs) were reported by 63.4%; the most common was upper respiratory infection (16.1%). Serious AEs were reported by 3.5% of the All-adalimumab Population, and serious infectious AEs by 1.2%, which include lung infection, pneumonia and tuberculosis [2 (0.5%) patients each]. There was one death (chronic heart failure). CONCLUSION: In these Chinese patients with moderate-to-severe psoriasis, a significantly greater percentage treated with adalimumab compared with placebo achieved efficacy endpoints at week 12 and efficacy was sustained to week 24. Safety results were consistent with the known adalimumab safety profile; no new safety signals were identified in the 24 weeks of treatment.


Subject(s)
Adalimumab/therapeutic use , Psoriasis/drug therapy , Adult , China , Double-Blind Method , Female , Humans , Male , Middle Aged , Placebos
5.
Br J Dermatol ; 171(6): 1434-42, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25040429

ABSTRACT

BACKGROUND: Quantification of disease severity supports the development of evidence-based treatments. Assessments to capture clinical improvement in hidradenitis suppurativa (HS) can be improved. OBJECTIVES: This study aimed to validate the Hidradenitis Suppurativa Clinical Response (HiSCR), which is defined as a ≥ 50% reduction in inflammatory lesion count (sum of abscesses and inflammatory nodules, AN), and no increase in abscesses or draining fistulas in HS when compared with baseline as a meaningful clinical endpoint for HS treatment. METHODS: Patients with ≥ 3 ANs at baseline in a Phase II adalimumab trial for HS were included for analysis. HiSCR achievers vs. nonachievers were assessed at week 16 and week 52. Criteria measures included physician-rated assessments [Hurley stage, modified Sartorius score (MSS), and HS Physician's Global Assessment] and patient-reported outcomes (PROs: visual analogue pain scale, Dermatology Life Quality Index, and Work Productivity and Activity Impairment questionnaire). Test-retest reliability, convergent validity, responsiveness and predictive validity of HiSCR, and its meaningfulness to patients were assessed. RESULTS: Among 138 eligible study participants, the majority were female (69·6%) with a mean age of 36·7 years. The mean (median) MSS was 125·2 (85·5) at baseline. Test-retest reliability of the AN count was 0·91. HiSCR was significantly correlated with improvements in all physician-rated and PRO measures (Spearman's rho between -0·61 and -0·27, all P < 0·001). Improvements of all PROs in HiSCR achievers exceeded the respective meaningful improvement thresholds. CONCLUSIONS: In patients with HS with ≥ 3 ANs, HiSCR achievers had significant improvements in physician-rated and patient-reported HS disease severity and impact. HiSCR is a valid and meaningful endpoint for assessing HS treatment effectiveness in controlling inflammatory manifestations in this population.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Hidradenitis Suppurativa/drug therapy , Severity of Illness Index , Adalimumab , Adult , Female , Humans , Male , Pain/prevention & control , Pain Measurement , Quality of Life , Reproducibility of Results , Treatment Outcome
7.
Br J Dermatol ; 167(6): 1374-81, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22897348

ABSTRACT

BACKGROUND: Psoriasis is associated with poor health-related quality of life, including sleep impairment. OBJECTIVE: To assess the extent of sleep impairment, the effect of adalimumab on sleep and other patient-reported outcomes, and correlations between changes in these outcomes and sleep quality in patients with psoriasis. METHODS: Patients in the 16-week, open-label, Phase IIIb PROGRESS trial had chronic plaque psoriasis and suboptimal response to prior therapy (etanercept, methotrexate or narrowband ultraviolet B phototherapy). Adalimumab was self-injected subcutaneously (80 mg at week 0, then 40 mg every other week from week 1). The focus for this analysis was the Medical Outcomes Study Sleep Scale. Other patient-reported outcomes included the Dermatology Life Quality Index (DLQI), Psoriasis Area and Severity Index (PASI), Physician's Global Assessment, a visual analogue scale for psoriasis/psoriatic arthritis (PsA) pain, and the Work Productivity and Activity Index Questionnaire-Specific Health Problems. RESULTS: Patients with psoriasis had impaired sleep at baseline. The degree of sleep impairment was significantly associated with the extent of work productivity for all sleep measures and, for some sleep measures, was associated with DLQI impairment, clinical severity measured by PASI, the presence of PsA, and depression. Adalimumab treatment significantly improved sleep quality by 15% from baseline, as well as DLQI score, pain and work productivity. The improvement in sleep was partially explained (R(2 ) = 0·16, P < 0·001) by improvements in the objectively measured psoriasis signs in PASI. CONCLUSIONS: Adalimumab treatment improved sleep outcomes and other patient-reported outcomes including health-related quality of life, work productivity, daily activity and disease-related pain.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal, Humanized/therapeutic use , Psoriasis/drug therapy , Sleep Wake Disorders/drug therapy , Absenteeism , Adalimumab , Adult , Drug Substitution , Female , Humans , Male , Middle Aged , Psoriasis/physiopathology , Quality of Life , Severity of Illness Index , Sleep Wake Disorders/physiopathology , Surveys and Questionnaires , Treatment Outcome , Work
8.
Br J Dermatol ; 167(3): 658-67, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22564148

ABSTRACT

BACKGROUND: The clinical utility of increasing to weekly adalimumab therapy in patients with psoriasis with inadequate response to every other week (eow) dosing is unknown. OBJECTIVES: (i) To determine the effectiveness of escalating adalimumab dosage from 40 mg eow to 40 mg weekly in patients with < PASI 50 response following ≥ 24 weeks treatment. (ii) To identify retrospectively characteristics of patients likely to benefit from dose escalation using classification and regression tree analysis. (iii) To assess cost implications for allowing dose escalation from the private payers' perspective. METHODS: Patients with moderate-to-severe psoriasis who had received blinded adalimumab 40 mg eow or placebo in antecedent phase II/III studies could enrol in an open-label extension (OLE) and initially receive open-label adalimumab 40 mg eow (EOW population). On/after week 24 (OLE), patients with < PASI 50 response relative to baseline of antecedent study could increase to 40 mg weekly. The dosage escalation population continued on weekly dosing until achieving PASI 75 response, then resumed eow dosing. Study visits were 6/12 weeks after dosage escalation, and every 12 weeks thereafter. The percentage of patients who achieved PASI 75 response following dosage escalation was determined (missing PASI scores imputed as nonresponse). Safety was assessed for the dosage escalation population and for all adalimumab exposure that did not follow dosage escalation in the EOW set. RESULTS: In total, 349/1256 (27·8%) patients underwent dosage escalation (OLE). At 12/24 weeks after dosage escalation, 93/349 (26·6%)/133/349 (38·1%) were PASI 75 responders or resumed eow dosing. Secondary nonresponders, patients weighing ≤ 102 kg, and those with disease duration < 8·3 years were most likely to benefit from dose escalation. Rates of serious/serious infectious/malignant (excluding nonmelanoma skin cancers or lymphoma) adverse events were 6·8/0·9/1·4 events per 100 patient-years (dosage escalation population); comparable rates in the EOW set were 6·5/1·2/0·5 events per 100 patient-years. CONCLUSIONS: Most patients did not require dose escalation. By 12 weeks after dose escalation, one-quarter achieved substantial clinical improvement. Safety results were similar between patients who dosage-escalated and those who did not.


Subject(s)
Antibodies, Monoclonal, Humanized/administration & dosage , Dermatologic Agents/administration & dosage , Psoriasis/drug therapy , Adalimumab , Adult , Antibodies, Monoclonal, Humanized/adverse effects , Antibodies, Monoclonal, Humanized/economics , Dermatologic Agents/adverse effects , Dermatologic Agents/economics , Dose-Response Relationship, Drug , Drug Administration Schedule , Drug Costs , Female , Humans , Injections , Male , Psoriasis/economics , Treatment Outcome
9.
Br J Dermatol ; 162(6): 1349-58, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20394634

ABSTRACT

BACKGROUND: Safety of tumour necrosis factor (TNF) antagonists is a primary concern for clinicians prescribing them to patients with psoriasis. OBJECTIVES: To determine the benefit-risk balance of TNF antagonists in psoriasis. METHODS: Through integrated analyses of published literature, we calculated the number needed to treat (NNT) for various efficacy measures and the number needed to harm (NNH) for various adverse events for approved dosing regimens of adalimumab, etanercept and infliximab. Integrated analyses that included open-label safety data from TNF-antagonist clinical trials were also conducted. RESULTS: PASI 75 treatment effect data from the literature result in NNT values of 1·6 (95% confidence interval, CI 1·5-1·7) for adalimumab 40 mg every other week; 3·2 (95% CI 2·8-3·7) for etanercept 50 mg weekly or 25 mg twice weekly, and 2·3 (95% CI 2·1-2·5) for etanercept 50 mg twice weekly; and 1·4 (95% CI 1·3-1·5) for infliximab 5 mg kg(-1) dosing. For serious noninfectious, serious infectious and malignant adverse events, point estimates of the NNHs are generally at least two orders of magnitude larger than the NNTs, and the 95% CIs for the NNHs for adalimumab, etanercept and infliximab overlap. Analyses that included open-label data corroborated, with increased exposure to study agents, the low risk of adverse events observed in placebo-controlled periods. CONCLUSIONS: These analyses demonstrated that, during the initial year of treatment, the likelihood of success with anti-TNF therapy for psoriasis was several orders of magnitude greater than the likelihood of serious toxicity.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antibodies, Monoclonal/therapeutic use , Immunoglobulin G/therapeutic use , Psoriasis/drug therapy , Receptors, Tumor Necrosis Factor/therapeutic use , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adalimumab , Adult , Anti-Inflammatory Agents/adverse effects , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Etanercept , Female , Humans , Immunoglobulin G/adverse effects , Infliximab , Male , Middle Aged , Risk Assessment/methods
10.
J Virol ; 75(9): 4332-42, 2001 May.
Article in English | MEDLINE | ID: mdl-11287582

ABSTRACT

BPHE-1 cells, which harbor 50 to 200 viral episomes, encapsidate viral genome and generate infectious bovine papillomavirus type 1 (BPV1) upon coexpression of capsid proteins L1 and L2 of BPV1, but not coexpression of BPV1 L1 and human papillomavirus type 16 (HPV16) L2. BPV1 L2 bound in vitro via its C-terminal 85 residues to purified L1 capsomers, but not with intact L1 virus-like particles in vitro. However, when the efficiency of BPV1 L1 coimmunoprecipitation with a series of BPV1 L2 deletion mutants was examined in vivo, the results suggested that residues 129 to 246 and 384 to 460 contain independent L1 interaction domains. An L2 mutant lacking the C-terminal L1 interaction domain was impaired for encapsidation of the viral genome. Coexpression of BPV1 L1 and a chimeric L2 protein composed of HPV16 L2 residues 1 to 98 fused to BPV1 L2 residues 99 to 469 generated infectious virions. However, inefficient encapsidation was seen when L1 was coexpressed with either BPV1 L2 with residues 91 to 246 deleted or with BPV1 L2 with residues 1 to 225 replaced with HPV16 L2. Impaired genome encapsidation did not correlate closely with impairment of the L2 proteins either to localize to promyelocytic leukemia oncogenic domains (PODs) or to induce localization of L1 or E2 to PODs. We conclude that the L1-binding domain located near the C terminus of L2 may bind L1 prior to completion of capsid assembly, and that both L1-binding domains of L2 are required for efficient encapsidation of the viral genome.


Subject(s)
Bovine papillomavirus 1/metabolism , Capsid Proteins , Capsid/metabolism , Genome, Viral , Virus Assembly/physiology , Animals , Binding Sites , Bovine papillomavirus 1/genetics , Capsid/genetics , Cattle , Cell Line , Cricetinae , Humans , Mutagenesis , Oncogene Proteins, Viral/genetics , Oncogene Proteins, Viral/metabolism , Papillomaviridae/genetics , Papillomaviridae/metabolism , Precipitin Tests
12.
Clin Exp Dermatol ; 19(3): 246-8, 1994 May.
Article in English | MEDLINE | ID: mdl-8033389

ABSTRACT

Drug reactions simulating mycosis fungoides have been described most frequently for phenytoin, angiotensin-converting enzyme inhibitors, and carbamazepine. The first reported case of a quinine-induced drug reaction that histologically mimicked mycosis fungoides is described.


Subject(s)
Dermatitis, Photoallergic/pathology , Mycosis Fungoides/pathology , Quinine/adverse effects , Skin Neoplasms/pathology , Aged , Dermatitis, Photoallergic/etiology , Diagnosis, Differential , Female , Humans
13.
J Biol Chem ; 267(16): 11476-82, 1992 Jun 05.
Article in English | MEDLINE | ID: mdl-1317869

ABSTRACT

Signal recognition particle (SRP) induces elongation arrest of nascent presecretory proteins as the signal peptide protrudes from the large ribosomal subunit. To examine the relationship between the size of the precursor and extent of SRP mediated inhibition of polypeptide chain elongation, we performed in vitro translation experiments in the presence of SRP using a series of truncated preproinsulin mRNA molecules. These precursors possessed the same NH2 terminus as native preproinsulin followed by progressively shorter COOH termini. SRP inhibited translation of precursors as short as 64 amino acids in length, however, the extent of inhibition diminished for shorter precursors. This correlated with a reduction in the time required for ribosomes to transit through the mRNA encoding the shortened precursors. By exploiting a chimeric protein comprising the first 71 residues of preproinsulin fused to the bacterial cytoplasmic enzyme chloramphenicol acetyltransferase, we demonstrate that the largest size a nascent chain can reach and still be susceptible to SRP-mediated elongation arrest is approximately 17 kDa. Our data support the model that SRP binding to the signal peptide is a reversible process even in the absence of microsomal membranes, and that SRP can arrest polypeptide chain elongation at multiple stages during translation.


Subject(s)
Endoplasmic Reticulum/metabolism , Proinsulin/metabolism , Protein Precursors/metabolism , Ribonucleoproteins/pharmacology , Animals , Biological Transport , Cell Membrane , Electrophoresis, Polyacrylamide Gel , Fishes , Insulin , Plasmids , Protein Biosynthesis/drug effects , Protein Synthesis Inhibitors , RNA, Messenger/metabolism , Signal Recognition Particle
14.
J Biol Chem ; 265(13): 7478-84, 1990 May 05.
Article in English | MEDLINE | ID: mdl-2185250

ABSTRACT

Nascent preproinsulin interacts with endoplasmic reticulum membranes after approximately 70-80 residues of the 116-amino acid precursor are polymerized (Eskridge, E. M., and Shields, D. (1983) J. Biol. Chem. 258, 11487-11491). To understand the relationship between the size of a nascent presecretory polypeptide and the efficiency of its translocation across the endoplasmic reticulum membrane, recombinant DNA molecules were generated that encoded a series of preproinsulin derivatives with the same NH2 terminus as preproinsulin and progressively shorter COOH termini. The DNA was transcribed, the in vitro transcription products were translated in the wheat germ cell-free translation system, and the interaction of the resulting truncated polypeptides with signal recognition particle (SRP) and with microsomal membranes was analyzed. Truncations composed of 78 and 64 amino acids were translocated across the endoplasmic reticulum membrane, and translocation was found to be strictly co-translational and SRP-dependent. Translocation efficiency at low membrane concentrations was reduced for these truncated molecules relative to full-length preproinsulin. Most significantly, translation of the 64-residue polypeptide was arrested by SRP after only 50 amino acids were polymerized. This suggests that the initial interaction of nascent secretory proteins with SRP occurs when only 10 residues of the signal peptide protrude from the large ribosomal subunit.


Subject(s)
Endoplasmic Reticulum/metabolism , Proinsulin/genetics , Protein Precursors/genetics , Protein Processing, Post-Translational , Protein Sorting Signals/metabolism , Animals , Cloning, Molecular , Cystine/metabolism , DNA-Directed RNA Polymerases/metabolism , Escherichia coli/enzymology , Gene Library , Insulin , Leucine/metabolism , Microsomes/metabolism , Molecular Weight , Plasmids , Proinsulin/metabolism , Protein Binding , Protein Biosynthesis , Protein Precursors/metabolism , Transcription, Genetic , Triticum/metabolism
15.
J Mol Endocrinol ; 2(2): 137-44, 1989 Mar.
Article in English | MEDLINE | ID: mdl-2673284

ABSTRACT

In-vitro translation of anglerfish islet mRNA revealed three glucagon precursors (preproglucagons): one with Mr 16,000 and two with Mr 14,000. The two Mr 14,000 precursors were well separated upon isoelectric focusing gels (pI values of 7.2 and 7.3), but had identical peptide maps. Translation of hybrid-selected Mr 14,000 preproglucagon mRNA in the presence of microsomal vesicles revealed that both precursors were processed to the same proglucagon. Northern blot analysis detected two mRNA species encoding Mr 14,000 precursor. A full-length Mr 14,000 preproglucagon cDNA was subcloned into a transcription vector, and coupled in-vitro transcription-translation was performed; surprisingly, both Mr 14,000 precursors were synthesized. To test whether acetylation of the free amino terminus generated the more acidic precursor, acetylase activity was partially inactivated with the inhibitor S-acetonyl-CoA, and acetyl-CoA was depleted by addition of oxaloacetate and citrate synthetase. Under these conditions, the level of the most basic preproglucagon was greatly enhanced, but when exogenous acetyl-CoA was added, the acidic form predominated. We conclude that acetylation generates the acidic precursor, and we discuss the implications of our findings for the biogenesis of other peptide hormones.


Subject(s)
Glucagon/biosynthesis , Protein Biosynthesis , Protein Precursors/biosynthesis , Acetylation , Amino Acid Sequence , Animals , DNA/metabolism , Fishes , Glucagon/analysis , Glucagon/genetics , Islets of Langerhans/metabolism , Molecular Weight , Proglucagon , Protein Precursors/analysis , Protein Precursors/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism
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