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Importance: The clinical effects of risankizumab (a monoclonal antibody that selectively targets the p19 subunit of IL-23) for the treatment of ulcerative colitis are unknown. Objective: To evaluate the efficacy and safety of risankizumab when administered as an induction and a maintenance therapy for patients with ulcerative colitis. Design, Setting, and Participants: Two phase 3 randomized clinical trials were conducted. The induction trial was conducted at 261 clinical centers (in 41 countries) and enrolled 977 patients from November 5, 2020, to August 4, 2022 (final follow-up on May 16, 2023). The maintenance trial was conducted at 238 clinical centers (in 37 countries) and enrolled 754 patients from August 28, 2018, to March 30, 2022 (final follow-up on April 11, 2023). Eligible patients had moderately to severely active ulcerative colitis; a history of intolerance or inadequate response to 1 or more conventional therapies, advanced therapies, or both types of therapies; and no prior exposure to risankizumab. Interventions: For the induction trial, patients were randomized 2:1 to receive 1200 mg of risankizumab or placebo administered intravenously at weeks 0, 4, and 8. For the maintenance trial, patients with a clinical response (determined using the adapted Mayo score) after intravenous treatment with risankizumab were randomized 1:1:1 to receive subcutaneous treatment with 180 mg or 360 mg of risankizumab or placebo (no longer receiving risankizumab) every 8 weeks for 52 weeks. Main Outcomes and Measures: The primary outcome was clinical remission (stool frequency score ≤1 and not greater than baseline, rectal bleeding score of 0, and endoscopic subscore ≤1 without friability) at week 12 for the induction trial and at week 52 for the maintenance trial. Results: Among the 975 patients analyzed in the induction trial (aged 42.1 [SD, 13.8] years; 586/973 [60.1%] were male; and 677 [69.6%] were White), the clinical remission rates at week 12 were 132/650 (20.3%) for 1200 mg of risankizumab and 20/325 (6.2%) for placebo (adjusted between-group difference, 14.0% [95% CI, 10.0%-18.0%], P < .001). Among the 548 patients analyzed in the maintenance trial (aged 40.9 [SD, 14.0] years; 313 [57.1%] were male; and 407 [74.3%] were White), the clinical remission rates at week 52 were 72/179 (40.2%) for 180 mg of risankizumab, 70/186 (37.6%) for 360 mg of risankizumab, and 46/183 (25.1%) for placebo (adjusted between-group difference for 180 mg of risankizumab vs placebo, 16.3% [97.5% CI, 6.1%-26.6%], P < .001; adjusted between-group difference for 360 mg of risankizumab vs placebo, 14.2% [97.5% CI, 4.0%-24.5%], P = .002). No adverse event signals were detected in the treatment groups. Conclusion and Relevance: Compared with placebo, risankizumab improved clinical remission rates in an induction trial and in a maintenance trial for patients with moderately to severely active ulcerative colitis. Further study is needed to identify benefits beyond the 52-week follow-up. Trial Registration: ClinicalTrials.gov Identifiers: NCT03398148 and NCT03398135.
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BACKGROUND: The efficacy and safety of risankizumab as compared with ustekinumab in patients with Crohn's disease are unknown. METHODS: In this phase 3b, multicenter, open-label, randomized, controlled trial with blinded assessment of end points, patients with moderate-to-severe Crohn's disease who had had an inadequate response to anti-tumor necrosis factor (TNF) therapy or unacceptable side effects with such therapy were randomly assigned to receive risankizumab or ustekinumab at standard doses for 48 weeks. The two primary end points, which were tested sequentially, were clinical remission at week 24 (defined as a Crohn's Disease Activity Index score of <150 [range, 0 to 600, with higher scores indicating more severe disease activity]), which was analyzed in the first 50% of patients to complete the week 24 visit, with a noninferiority margin of 10 percentage points; and endoscopic remission at week 48 (defined as a score of ≤4, a decrease of ≥2 points from baseline, and no subscore >1 in any individual variable on the Simple Endoscopic Score for Crohn's Disease [range, 0 to 56, with higher scores indicating more severe disease]), which was analyzed for superiority in 100% of the patients. Safety was assessed in all patients who received at least one dose of risankizumab or ustekinumab. RESULTS: In the full intention-to-treat population for the efficacy analysis, 230 of 255 patients (90.2%) who received risankizumab and 193 of 265 patients (72.8%) who received ustekinumab completed all the assigned treatments. Both primary end points were met; risankizumab was noninferior to ustekinumab with respect to clinical remission at week 24 (58.6% vs. 39.5%; adjusted difference, 18.4 percentage points; 95% confidence interval [CI], 6.6 to 30.3) and superior to ustekinumab with respect to endoscopic remission at week 48 (31.8% vs. 16.2%; adjusted difference, 15.6 percentage points; 95% CI, 8.4 to 22.9; P<0.001). The incidence of adverse events appeared to be similar in the two groups. CONCLUSIONS: In this head-to-head clinical trial of risankizumab and ustekinumab involving patients with moderate-to-severe Crohn's disease who had had unacceptable side effects with anti-TNF therapy or an inadequate response to such therapy, risankizumab was noninferior to ustekinumab with respect to clinical remission at week 24 and superior with respect to endoscopic remission at week 48. (Funded by AbbVie; ClinicalTrials.gov number, NCT04524611.).
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Anticuerpos Monoclonales , Enfermedad de Crohn , Inducción de Remisión , Ustekinumab , Humanos , Enfermedad de Crohn/tratamiento farmacológico , Ustekinumab/uso terapéutico , Ustekinumab/efectos adversos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales/efectos adversos , Índice de Severidad de la Enfermedad , Análisis de Intención de Tratar , Adulto JovenRESUMEN
Risankizumab is a high-affinity neutralizing anti-interleukin (IL)-23 monoclonal antibody marketed in over 40 countries across the globe to treat several inflammatory diseases, such as plaque psoriasis (PsO), psoriatic arthritis (PsA), and Crohn's disease (CD). This paper reviews the regulatory approval, mechanism of action, pharmacokinetics (PKs)/pharmacodynamics, immunogenicity, and clinical efficacy and safety data for risankizumab, focusing on the three main approved indications. Risankizumab binds to the p19 subunit of IL-23 and inhibits IL-23 from interacting with the IL-23 receptor and subsequent signaling. Biomarker data obtained following treatment with risankizumab in multiple indications provided supportive evidence for downstream blockade of IL-23 signaling associated with disease pathology. The PKs of risankizumab is linear and time-independent, consistent with typical IgG1 monoclonal antibodies, across all evaluated indications. Risankizumab exhibited positive exposure-response relationships for efficacy with no apparent exposure-dependent worsening in safety. Immunogenicity to risankizumab had no major clinical consequences for either efficacy or safety. Efficacy and safety of risankizumab have been established in PsO, PsA, and CD in the pivotal clinical trials where superior benefit/risk profiles were demonstrated compared to placebo and/or active comparators. Moreover, safety evaluations in open-label extension studies following long-term treatment with risankizumab showed stable and favorable safety profiles consistent with shorter-term studies. These data formed the foundation for risankizumab's marketing approvals to treat multiple inflammatory diseases across the globe.
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Artritis Psoriásica , Enfermedad de Crohn , Humanos , Ciencia Traslacional Biomédica , Artritis Psoriásica/tratamiento farmacológico , Anticuerpos Monoclonales/efectos adversos , Interleucina-23RESUMEN
BACKGROUND AND AIMS: Anti-tumour necrosis factor [anti-TNF] therapy is widely used for the treatment of inflammatory bowel disease, yet many patients are primary non-responders, failing to respond to induction therapy. We aimed to identify blood gene expression differences between primary responders and primary non-responders to anti-TNF monoclonal antibodies [infliximab and adalimumab], and to predict response status from blood gene expression and clinical data. METHODS: The Personalised Anti-TNF Therapy in Crohn's Disease [PANTS] study is a UK-wide prospective observational cohort study of anti-TNF therapy outcome in anti-TNF-naive Crohn's disease patients [ClinicalTrials.gov identifier: NCT03088449]. Blood gene expression in 324 unique patients was measured by RNA-sequencing at baseline [week 0], and at weeks 14, 30, and 54 after treatment initiation [total sample sizeâ =â 814]. RESULTS: After adjusting for clinical covariates and estimated blood cell composition, baseline expression of major histocompatibility complex, antigen presentation, myeloid cell enriched receptor, and other innate immune gene modules was significantly higher in anti-TNF responders vs non-responders. Expression changes from baseline to week 14 were generally of consistent direction but greater magnitude [i.e. amplified] in responders, but interferon-related genes were upregulated uniquely in non-responders. Expression differences between responders and non-responders observed at week 14 were maintained at weeks 30 and 54. Prediction of response status from baseline clinical data, cell composition, and module expression was poor. CONCLUSIONS: Baseline gene module expression was associated with primary response to anti-TNF therapy in PANTS patients. However, these baseline expression differences did not predict response with sufficient sensitivity for clinical use.
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Enfermedad de Crohn , Humanos , Enfermedad de Crohn/tratamiento farmacológico , Enfermedad de Crohn/genética , Redes Reguladoras de Genes , Inhibidores del Factor de Necrosis Tumoral/uso terapéutico , Estudios Prospectivos , Inmunoterapia , Factor de Necrosis Tumoral alfaRESUMEN
BACKGROUND AND AIMS: This study assessed whether baseline triggering receptor expressed on myeloid cells [TREM-1] whole blood gene expression predicts response to anti-TNF therapy in patients with UC or CD. METHODS: TREM-1 whole blood gene expression was analysed by RNA sequencing [RNA-seq] in patients with moderately to severely active UC or CD treated with adalimumab in the Phase 3 SERENE-UC and SERENE-CD clinical trials. The predictive value of baseline TREM-1 expression was evaluated and compared according to endoscopic and clinical response vs non-response, and remission vs non-remission, at Weeks 8 and 52 [SERENE-UC], and Weeks 12 and 56 [SERENE-CD]. RESULTS: TREM-1 expression was analysed in 95 and 106 patients with UC and CD, respectively, receiving standard-dose adalimumab induction treatment. In SERENE-UC, baseline TREM-1 expression was not predictive of endoscopic response [p=0.48], endoscopic remission [p=0.53], clinical response [p=0.58] or clinical remission [p=0.79] at Week 8, or clinical response [p=0.60] at Week 52. However, an association was observed with endoscopic response [p=0.01], endoscopic remission [p=0.048], and clinical remission [p=0.04997] at Week 52. For SERENE-CD, baseline TREM-1 expression was not predictive of endoscopic response [p=0.56], endoscopic remission [p=0.33], clinical response [p=0.07], clinical remission [p=0.65] at Week 12, or endoscopic response [p=0.61], endoscopic remission [p=0.51], clinical response [p=0.62] or clinical remission [p=0.97] at Week 56. CONCLUSIONS: Baseline TREM-1 gene expression did not uniformly predict adalimumab response in SERENE clinical trials. Further research is needed to identify potential blood-based biomarkers predictive of response to anti-TNF therapy in patients with IBD.
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BACKGROUND AND AIMS: Anti-TNF treatment failure in patients with inflammatory bowel disease (IBD) is common and frequently related to low drug concentrations. In order to identify patients who may benefit from dose optimisation at the outset of anti-TNF therapy, we sought to define epigenetic biomarkers in whole blood at baseline associated with anti-TNF drug concentrations at week 14. METHODS: DNA methylation from 1,104 whole blood samples from 385 patients in the Personalised Anti-TNF Therapy in Crohn's disease (PANTS) study were assessed using the Illumina EPIC Beadchip (v1.0) at baseline, weeks 14, 30 and 54. We compared DNA methylation profiles in anti-TNF-treated patients who experienced primary non-response at week 14 and if they were assessed at subsequent time points, were not in remission at week 30 or 54 (infliximab n = 99, adalimumab n = 94), with patients who responded at week 14 and when assessed at subsequent time points, were in remission at week 30 or 54 (infliximab n = 99, adalimumab n = 93). RESULTS: Overall, between baseline and week 14, we observed 4,999 differentially methylated probes (DMPs) annotated to 2376 genes following anti-TNF treatment. Pathway analysis identified 108 significant gene ontology terms enriched in biological processes related to immune system processes and responses.Epigenome-wide association (EWAS) analysis identified 323 DMPs annotated to 210 genes at baseline associated with higher anti-TNF drug concentrations at week 14. Of these, 125 DMPs demonstrated shared associations with other common traits (proportion of shared CpGs compared to DMPs) including body mass index (23.2%), followed by CRP (11.5%), smoking (7.4%), alcohol consumption per day (7.1%) and IBD type (6.8%). EWAS of primary non-response to anti-TNF identified 20 DMPs that were associated with both anti-TNF drug concentration and primary non-response to anti-TNF with a strong correlation of the coefficients (Spearman's rho = -0.94, p < 0.001). CONCLUSION: Baseline DNA methylation profiles may be used as a predictor for anti-TNF drug concentration at week 14 to identify patients who may benefit from dose optimisation at the outset of anti-TNF therapy.
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BACKGROUND: There is a great unmet need for new therapeutics with novel mechanisms of action for patients with Crohn's disease. The ADVANCE and MOTIVATE studies showed that intravenous risankizumab, a selective p19 anti-interleukin (IL)-23 antibody, was efficacious and well tolerated as induction therapy. Here, we report the efficacy and safety of subcutaneous risankizumab as maintenance therapy. METHODS: FORTIFY is a phase 3, multicentre, randomised, double-blind, placebo-controlled, maintenance withdrawal study across 273 clinical centres in 44 countries across North and South America, Europe, Oceania, Africa, and the Asia-Pacific region that enrolled participants with clinical response to risankizumab in the ADVANCE or MOTIVATE induction studies. Patients in ADVANCE or MOTIVATE were aged 16-80 years with moderately to severely active Crohn's disease. Patients in the FORTIFY substudy 1 were randomly assigned again (1:1:1) to receive either subcutaneous risankizumab 180 mg, subcutaneous risankizumab 360 mg, or withdrawal from risankizumab to receive subcutaneous placebo (herein referred to as withdrawal [subcutaneous placebo]). Treatment was given every 8 weeks. Patients were stratified by induction dose, post-induction endoscopic response, and clinical remission status. Patients, investigators, and study personnel were masked to treatment assignments. Week 52 co-primary endpoints were clinical remission (Crohn's disease activity index [CDAI] in the US protocol, or stool frequency and abdominal pain score in the non-US protocol) and endoscopic response in patients who received at least one dose of study drug during the 52-week maintenance period. Safety was assessed in patients receiving at least one dose of study medication. This study is registered with ClinicalTrials.gov, NCT03105102. FINDINGS: 712 patients were initially assessed and, between April 9, 2018, and April 24, 2020, 542 patients were randomly assigned to either the risankizumab 180 mg group (n=179), the risankizumab 360 mg group (n=179), or the placebo group (n=184). Greater clinical remission and endoscopic response rates were reached with 360 mg risankizumab versus placebo (CDAI clinical remission was reached in 74 (52%) of 141 patients vs 67 (41%) of 164 patients, adjusted difference 15% [95% CI 5-24]; stool frequency and abdominal pain score clinical remission was reached in 73 (52%) of 141 vs 65 (40%) of 164, adjusted difference 15% [5-25]; endoscopic response 66 (47%) of 141 patients vs 36 (22%) of 164 patients, adjusted difference 28% [19-37]). Higher rates of CDAI clinical remission and endoscopic response (but not stool frequency and abdominal pain score clinical remission [p=0·124]) were also reached with risankizumab 180 mg versus withdrawal (subcutaneous placebo; CDAI clinical remission reached in 87 [55%] of 157 patients, adjusted difference 15% [95% CI 5-24]; endoscopic response 74 [47%] of 157, adjusted difference 26% [17-35]). Results for more stringent endoscopic and composite endpoints and inflammatory biomarkers were consistent with a dose-response relationship. Maintenance treatment was well tolerated. Adverse event rates were similar among groups, and the most frequently reported adverse events in all treatment groups were worsening Crohn's disease, arthralgia, and headache. INTERPRETATION: Subcutaneous risankizumab is a safe and efficacious treatment for maintenance of remission in patients with moderately to severely active Crohn's disease and offers a new therapeutic option for a broad range of patients by meeting endpoints that might change the future course of disease. FUNDING: AbbVie.
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Enfermedad de Crohn , Dolor Abdominal , Anticuerpos Monoclonales/efectos adversos , Enfermedad de Crohn/tratamiento farmacológico , Método Doble Ciego , HumanosRESUMEN
BACKGROUND: Risankizumab, an interleukin (IL)-23 p19 inhibitor, was evaluated for safety and efficacy as induction therapy in patients with moderately to severely active Crohn's disease. METHODS: ADVANCE and MOTIVATE were randomised, double-masked, placebo-controlled, phase 3 induction studies. Eligible patients aged 16-80 years with moderately to severely active Crohn's disease, previously showing intolerance or inadequate response to one or more approved biologics or conventional therapy (ADVANCE) or to biologics (MOTIVATE), were randomly assigned to receive a single dose of intravenous risankizumab (600 mg or 1200 mg) or placebo (2:2:1 in ADVANCE, 1:1:1 in MOTIVATE) at weeks 0, 4, and 8. We used interactive response technology for random assignment, with stratification by number of previous failed biologics, corticosteroid use at baseline, and Simple Endoscopic Score for Crohn's disease (SES-CD). All patients and study personnel (excluding pharmacists who prepared intravenous solutions) were masked to treatment allocation throughout the study. Coprimary endpoints were clinical remission (defined by Crohn's disease activity index [CDAI] or patient-reported outcome criteria [average daily stool frequency and abdominal pain score]) and endoscopic response at week 12. The intention-to-treat population (all eligible patients who received at least one dose of study drug in the 12-week induction period) was analysed for efficacy outcomes. Safety was assessed in all patients who received at least one dose of study drug. Both trials were registered on ClinicalTrials.gov, NCT03105128 (ADVANCE) and NCT03104413 (MOTIVATE), and are now complete. FINDINGS: Participants were enrolled between May 10, 2017, and Aug 24, 2020 (ADVANCE trial), and Dec 18, 2017 and Sept 9, 2020 (MOTIVATE trial). In ADVANCE, 931 patients were assigned to either risankizumab 600 mg (n=373), risankizumab 1200 mg (n=372), or placebo (n=186). In MOTIVATE, 618 patients were assigned to risankizumab 600 mg (n=206), risankizumab 1200 mg (n=205), or placebo (n=207). The primary analysis population comprised 850 participants in ADVANCE and 569 participants in MOTIVATE. All coprimary endpoints at week 12 were met in both trials with both doses of risankizumab (p values ≤0·0001). In ADVANCE, CDAI clinical remission rate was 45% (adjusted difference 21%, 95% CI 12-29; 152/336) with risankizumab 600 mg and 42% (17%, 8-25; 141/339) with risankizumab 1200 mg versus 25% (43/175) with placebo; stool frequency and abdominal pain score clinical remission rate was 43% (22%, 14-30; 146/336) with risankizumab 600 mg and 41% (19%, 11-27; 139/339) with risankizumab 1200 mg versus 22% (38/175) with placebo; and endoscopic response rate was 40% (28%, 21-35; 135/336) with risankizumab 600 mg and 32% (20%, 14-27; 109/339) with risankizumab 1200 mg versus 12% (21/175) with placebo. In MOTIVATE, CDAI clinical remission rate was 42% (22%, 13-31; 80/191) with risankizumab 600 mg and 40% (21%, 12-29; 77/191) with risankizumab 1200 mg versus 20% (37/187) with placebo; stool frequency and abdominal pain score clinical remission rate was 35% (15%, 6-24; 66/191) with risankizumab 600 mg and 40% (20%, 12-29; 76/191) with risankizumab 1200 mg versus 19% (36/187) with placebo; and endoscopic response rate was 29% (18%, 10-25; 55/191) with risankizumab 600 mg and 34% (23%, 15-31; 65/191) with risankizumab 1200 mg versus 11% (21/187) with placebo. The overall incidence of treatment-emergent adverse events was similar among the treatment groups in both trials. Three deaths occurred during induction (two in the placebo group [ADVANCE] and one in the risankizumab 1200 mg group [MOTIVATE]). The death in the risankizumab-treated patient was deemed unrelated to the study drug. INTERPRETATION: Risankizumab was effective and well tolerated as induction therapy in patients with moderately to severely active Crohn's disease. FUNDING: AbbVie.
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Productos Biológicos , Enfermedad de Crohn , Dolor Abdominal , Anticuerpos Monoclonales , Productos Biológicos/uso terapéutico , Enfermedad de Crohn/tratamiento farmacológico , Humanos , Quimioterapia de InducciónRESUMEN
AIMS: Ulcerative colitis and Crohn's disease, collectively known as inflammatory bowel disease (IBD), are chronic inflammatory disorders of the intestine for which key elements in disease initiation and perpetuation are defects in epithelial barrier integrity. Achieving mucosal healing is essential to ameliorate disease outcome and so new therapies leading to epithelial homeostasis and repair are under investigation. This study was designed to determine the mechanisms by which IL-22 regulates intestinal epithelial cell function. MAIN METHODS: Human intestinal organoids and resections, as well as mice were used to evaluate the effect of IL-22 on stem cell expansion, proliferation and expression of mucus components. IL-22 effect on barrier function was assessed in polarized T-84 cell monolayers. Butyrate co-treatments and organoid co-cultures with immune cells were performed to monitor the impact of microbial-derived metabolites and inflammatory environments on IL-22 responses. KEY FINDINGS: IL-22 led to epithelial stem cell expansion, proliferation, barrier dysfunction and anti-microbial peptide production in human and mouse models evaluated. IL-22 also altered the mucus layer by inducing an increase in membrane mucus but a decrease in secreted mucus and goblet cell content. IL-22 had the same effect on anti-microbial peptides and membrane mucus in both healthy and IBD human samples. In contrast, this IL-22-associated epithelial phenotype was different when treatments were performed in presence of butyrate and organoids co-cultured with immune cells. SIGNIFICANCE: Our data indicate that IL-22 promotes epithelial regeneration, innate defense and membrane mucus production, strongly supporting the potential clinical utility of IL-22 as a mucosal healing therapy in IBD.
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Células Epiteliales/fisiología , Homeostasis/fisiología , Interleucinas/fisiología , Interleucinas/uso terapéutico , Mucosa Intestinal/fisiología , Animales , Línea Celular , Técnicas de Cocultivo , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/patología , Células Epiteliales/efectos de los fármacos , Homeostasis/efectos de los fármacos , Humanos , Interleucinas/farmacología , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Organoides/efectos de los fármacos , Organoides/fisiología , Interleucina-22RESUMEN
T cells are classically recognized as distinct subsets that express αß or γδ TCRs. We identify a novel population of T cells that coexpress αß and γδ TCRs in mice and humans. These hybrid αß-γδ T cells arose in the murine fetal thymus by day 16 of ontogeny, underwent αß TCR-mediated positive selection into CD4+ or CD8+ thymocytes, and constituted up to 10% of TCRδ+ cells in lymphoid organs. They expressed high levels of IL-1R1 and IL-23R and secreted IFN-γ, IL-17, and GM-CSF in response to canonically restricted peptide antigens or stimulation with IL-1ß and IL-23. Hybrid αß-γδ T cells were transcriptomically distinct from conventional γδ T cells and displayed a hyperinflammatory phenotype enriched for chemokine receptors and homing molecules that facilitate migration to sites of inflammation. These proinflammatory T cells promoted bacterial clearance after infection with Staphylococcus aureus and, by licensing encephalitogenic Th17 cells, played a key role in the development of autoimmune disease in the central nervous system.
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Inflamación/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Linfocitos T/inmunología , Animales , Biomarcadores/metabolismo , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Humanos , Inflamación/patología , Activación de Linfocitos/inmunología , Ratones Endogámicos C57BL , Fenotipo , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T gamma-delta/genética , Infecciones Estafilocócicas/inmunología , Staphylococcus aureus/fisiología , Transcripción Genética , Transcriptoma/genéticaRESUMEN
SpoIIIE/FtsK ATPases are central players in bacterial chromosome segregation. It remains unclear how these DNA translocases harness chemical energy (ATP turnover) to perform mechanical work (DNA movement). Bacillus subtilis sporulation provides a dramatic example of intercompartmental DNA transport, in which SpoIIIE moves 70% of the chromosome across the division plane. To understand the mechanistic requirements for DNA translocation, we investigated the DNA translocation defect of a classical nontranslocating allele, spoIIIE36. We found that the translocation phenotype is caused by a single substitution, a change of valine to methionine at position 429 (V429M), within the motor of SpoIIIE. This substitution is located at the base of a hinge between the RecA-like ß domain and the α domain, which is a domain unique to the SpoIIIE/FtsK family and currently has no known function. V429M interferes with both protein-DNA interactions and oligomer assembly. These mechanistic defects disrupt coordination between ATP turnover and DNA interaction, effectively uncoupling ATP hydrolysis from DNA movement. Our data provide the first functional evidence for the importance of the hinge in DNA translocation.
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Bacillus subtilis/fisiología , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Proteínas Bacterianas/genética , ADN Bacteriano , Variación Genética , Modelos Moleculares , Datos de Secuencia Molecular , Conformación Proteica , Estructura Terciaria de Proteína , Esporas Bacterianas/fisiologíaRESUMEN
Bacterial chromosome segregation utilizes highly conserved directional translocases of the SpoIIIE/FtsK family. These proteins employ an accessory DNA-binding domain (γ) to dictate directionality of DNA transport. It remains unclear how the interaction of γ with specific recognition sequences coordinates directional DNA translocation. We demonstrate that the γ domain of SpoIIIE inhibits ATPase activity of the motor domain in the absence of DNA but stimulates ATPase activity through sequence-specific DNA recognition. Furthermore, we observe that communication between γ subunits is necessary for both regulatory roles. Consistent with these findings, the γ domain is necessary for robust DNA transport along the length of the chromosome in vivo. Together, our data reveal that directional activation involves allosteric regulation of ATP turnover through coordinated action of γ domains. Thus, we propose a coordinated stimulation model in which γ-γ communication is required to translate DNA sequence information from each γ to its respective motor domain.
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Adenosina Trifosfatasas/metabolismo , Bacillus subtilis/enzimología , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , ADN Bacteriano/metabolismo , Regulación Alostérica , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Transporte Biológico , Datos de Secuencia Molecular , Mutación/genética , Unión Proteica , Estructura Terciaria de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Relación Estructura-ActividadRESUMEN
BACKGROUND: Structure-based drug design (SBDD) can accelerate inhibitor lead design and optimization, and efficient methods including protein purification, characterization, crystallization, and high-resolution diffraction are all needed for rapid, iterative structure determination. Janus kinases are important targets that are amenable to structure-based drug design. Here we present the first mouse Tyk2 crystal structures, which are complexed to 3-aminoindazole compounds. RESULTS: A comprehensive construct design effort included N- and C-terminal variations, kinase-inactive mutations, and multiple species orthologs. High-throughput cloning and expression methods were coupled with an abbreviated purification protocol to optimize protein solubility and stability. In total, 50 Tyk2 constructs were generated. Many displayed poor expression, inadequate solubility, or incomplete affinity tag processing. One kinase-inactive murine Tyk2 construct, complexed with an ATP-competitive 3-aminoindazole inhibitor, provided crystals that diffracted to 2.5-2.6 Å resolution. This structure revealed initial "hot-spot" regions for SBDD, and provided a robust platform for ligand soaking experiments. Compared to previously reported human Tyk2 inhibitor crystal structures (Chrencik et al. (2010) J Mol Biol 400:413), our structures revealed a key difference in the glycine-rich loop conformation that is induced by the inhibitor. Ligand binding also conferred resistance to proteolytic degradation by thermolysin. As crystals could not be obtained with the unliganded enzyme, this enhanced stability is likely important for successful crystallization and inhibitor soaking methods. CONCLUSIONS: Practical criteria for construct performance and prioritization, the optimization of purification protocols to enhance protein yields and stability, and use of high-throughput construct exploration enable structure determination methods early in the drug discovery process. Additionally, specific ligands stabilize Tyk2 protein and may thereby enable crystallization.
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Diseño de Fármacos , Indazoles/química , Indazoles/farmacología , TYK2 Quinasa/antagonistas & inhibidores , TYK2 Quinasa/química , Secuencia de Aminoácidos , Animales , Cristalización , Cristalografía por Rayos X , Estabilidad de Enzimas/efectos de los fármacos , Humanos , Quinasas Janus/antagonistas & inhibidores , Quinasas Janus/metabolismo , Ratones , Datos de Secuencia Molecular , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Estructura Secundaria de Proteína , Proteolisis/efectos de los fármacos , Relación Estructura-Actividad , TYK2 Quinasa/aislamiento & purificaciónRESUMEN
Terminally misfolded proteins that accumulate in the endoplasmic reticulum (ER) are dislocated and targeted for ubiquitin-dependent destruction by the proteasome. UBC6e is a tail-anchored E2 ubiquitin-conjugating enzyme that is part of a dislocation complex nucleated by the ER-resident protein SEL1L. Little is known about the turnover of tail-anchored ER proteins. We constructed a set of UBC6e transmembrane domain replacement mutants and found that the tail anchor of UBC6e is vital for its function, its stability, and its mode of membrane integration, the last step dependent on the ASNA1/TRC40 chaperone. We constructed a tail-anchored UBC6e variant that requires for its removal from the ER membrane not only YOD1 and p97, two cytosolic proteins involved in the extraction of ER transmembrane or luminal proteins, but also UBXD8, AUP1 and members of the Derlin family. Degradation of tail-anchored proteins thus relies on components that are also used in other aspects of protein quality control in the ER.