Synergistic Actions of Hematopoietic and Mesenchymal Stem/Progenitor Cells in Vascularizing Bioengineered Tissues

Poor angiogenesis is a major road block for tissue repair. The regeneration of virtually all tissues is limited by angiogenesis, given the diffusion of nutrients, oxygen, and waste products is limited to a few hundred micrometers. We postulated that co-transplantation of hematopoietic and mesenchymal stem/progenitor cells improves angiogenesis of tissue repair and hence the outcome of regeneration. In this study, we tested this hypothesis by using bone as a model whose regeneration is impaired unless it is vascularized. Hematopoietic stem/progenitor cells (HSCs) and mesenchymal stem/progenitor cells (MSCs) were isolated from each of three healthy human bone marrow samples and reconstituted in a porous scaffold. MSCs were seeded in micropores of 3D calcium phosphate (CP) scaffolds, followed by infusion of gel-suspended CD34+ hematopoietic cells. Co-transplantation of CD34+ HSCs and CD34− MSCs in microporous CP scaffolds subcutaneously in the dorsum of immunocompromized mice yielded vascularized tissue. The average vascular number of co-transplanted CD34+ and MSC scaffolds was substantially greater than MSC transplantation alone. Human osteocalcin was expressed in the micropores of CP scaffolds and was significantly increased upon co-transplantation of MSCs and CD34+ cells. Human nuclear staining revealed the engraftment of transplanted human cells in vascular endothelium upon co-transplantation of MSCs and CD34+ cells. Based on additional in vitro results of endothelial differentiation of CD34+ cells by vascular endothelial growth factor (VEGF), we adsorbed VEGF with co-transplanted CD34+ and MSCs in the microporous CP scaffolds in vivo, and discovered that vascular number and diameter further increased, likely owing to the promotion of endothelial differentiation of CD34+ cells by VEGF. Together, co-transplantation of hematopoietic and mesenchymal stem/progenitor cells may improve the regeneration of vascular dependent tissues such as bone, adipose, muscle and dermal grafts, and may have implications in the regeneration of internal organs

Occupancy by key transcription factors is a more accurate predictor of enhancer activity than histone modifications or chromatin accessibility

BACKGROUND: Regulated gene expression controls organismal development, and variation in regulatory patterns has been implicated in complex traits. Thus accurate prediction of enhancers is important for further understanding of these processes. Genome-wide measurement of epigenetic features, such as histone modifications and occupancy by transcription factors, is improving enhancer predictions, but the contribution of these features to prediction accuracy is not known. Given the importance of the hematopoietic transcription factor TAL1 for erythroid gene activation, we predicted candidate enhancers based on genomic occupancy by TAL1 and measured their activity. Contributions of multiple features to enhancer prediction were evaluated based on the results of these and other studies. RESULTS: TAL1-bound DNA segments were active enhancers at a high rate both in transient transfections of cultured cells (39 of 79, or 56%) and transgenic mice (43 of 66, or 65%). The level of binding signal for TAL1 or GATA1 did not help distinguish TAL1-bound DNA segments as active versus inactive enhancers, nor did the density of regulation-related histone modifications. A meta-analysis of results from this and other studies (273 tested predicted enhancers) showed that the presence of TAL1, GATA1, EP300, SMAD1, H3K4 methylation, H3K27ac, and CAGE tags at DNase hypersensitive sites gave the most accurate predictors of enhancer activity, with a success rate over 80% and a median threefold increase in activity. Chromatin accessibility assays and the histone modifications H3K4me1 and H3K27ac were sensitive for finding enhancers, but they have high false positive rates unless transcription factor occupancy is also included. CONCLUSIONS: Occupancy by key transcription factors such as TAL1, GATA1, SMAD1, and EP300, along with evidence of transcription, improves the accuracy of enhancer predictions based on epigenetic features. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13072-015-0009-5) contains supplementary material, which is available to authorized users

Emergence of SARS-CoV-2 with Dual-Drug Resistant Mutations During a Long-Term Infection in a Kidney Transplant Recipient [Corrigendum]

Tanino Y, Nishioka K, Yamamoto C, et al. Infect Drug Resist. 2024:17:531–541. Our authors have advised that there are two sentences that needed revision in the abstract section of the published paper. E340A/V792I is incorrectly described as E340K/V791I. The second sentence in “Results” section in the Abstract on page 531 should read from “The day 23 isolate harboring S:E340K/RdRp:V791I was resistant to both sotrovimab and RDV, showing 364- and 2.73-fold higher resistance respectively, compared with the wild-type.” to “The day 23 isolate harboring S:E340A/RdRp:V792I was resistant to both sotrovimab and RDV, showing 364- and 2.73-fold higher resistance respectively, compared with the wild-type.” The first sentence in “Conclusion” section in the Abstract on page 531 should read from Drug-resistant variants with double mutations (S:E340K/RdRp:V791I) became dominant within 23 days after starting treatment, suggesting that even a combination therapy involving sotrovimab and RDV, dual-drug resistant viruses may emerge rapidly in immunocompromised patients.” to “Drug-resistant variants with double mutations (S:E340A/RdRp:V792I) became dominant within 23 days after starting treatment, suggesting that even a combination therapy involving sotrovimab and RDV, dual-drug resistant viruses may emerge rapidly in immunocompromised patients.” The authors confirm that these changes do not affect the interpretation of the results and consider them to be typographical error only. The authors apologize for these errors

Long-term efficacy and safety of ruxolitinib versus best available therapy in polycythaemia vera (RESPONSE): 5-year follow up of a phase 3 study

Background: Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due to mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a JAK 1 and JAK 2 inhibitor, showed superiority over best available therapy in a phase 2 study in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. We aimed to compare the long-term safety and efficacy of ruxolitinib with best available therapy in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. Methods: We report the 5-year results for a randomised, open-label, phase 3 study (RESPONSE) that enrolled patients at 109 sites across North America, South America, Europe, and the Asia-Pacific region. Patients (18 years or older) with polycythaemia vera who were resistant to or intolerant of hydroxyurea were randomly assigned 1:1 to receive either ruxolitinib or best available therapy. Patients randomly assigned to the ruxolitinib group received the drug orally at a starting dose of 10 mg twice a day. Single-agent best available therapy comprised hydroxyurea, interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or observation without pharmacological treatment. The primary endpoint, composite response (patients who achieved both haematocrit control without phlebotomy and 35% or more reduction from baseline in spleen volume) at 32 weeeks was previously reported. Patients receiving best available therapy could cross over to ruxolitinib after week 32. We assessed the durability of primary composite response, complete haematological remission, overall clinicohaematological response, overall survival, patient-reported outcomes, and safety after 5-years of follow-up. This study is registered with ClinicalTrials.gov, NCT01243944. Findings: We enrolled patients between Oct 27, 2010, and Feb 13, 2013, and the study concluded on Feb 9, 2018. Of 342 individuals screened for eligibility, 222 patients were randomly assigned to receive ruxolitinib (n=110, 50%) or best available therapy (n=112, 50%). The median time since polycythaemia vera diagnosis was 8\ub72 years (IQR 3\ub79\u201312\ub73) in the ruxolitinib group and 9\ub73 years (4\ub79\u201313\ub78) in the best available therapy group. 98 (88%) of 112 patients initially randomly assigned to best available therapy crossed over to receive ruxolitinib and no patient remained on best available therapy after 80 weeks of study. Among 25 primary responders in the ruxolitinib group, six had progressed at the time of final analysis. At 5 years, the probability of maintaining primary composite response was 74% (95% CI 51\u201388). The probability of maintaining complete haematological remission was 55% (95% CI 32\u201373) and the probability of maintaining overall clinicohaematological responses was 67% (54\u201377). In the intention-to-treat analysis not accounting for crossover, the probability of survival at 5 years was 91\ub79% (84\ub74\u201395\ub79) with ruxolitinib therapy and 91\ub70% (82\ub78\u201395\ub74) with best available therapy. Anaemia was the most common adverse event in patients receiving ruxolitinib (rates per 100 patient-years of exposure were 8\ub79 for ruxolitinib and 8\ub78 for the crossover population), though most anaemia events were mild to moderate in severity (grade 1 or 2 anaemia rates per 100 patient-years of exposure were 8\ub70 for ruxolitinib and 8\ub72 for the crossover population). Non-haematological adverse events were generally lower with long-term ruxolitinib treatment than with best available therapy. Thromboembolic events were lower in the ruxolitinib group than the best available therapy group. There were two on-treatment deaths in the ruxolitinib group. One of these deaths was due to gastric adenocarcinoma, which was assessed by the investigator as related to ruxolitinib treatment. Interpretation: We showed that ruxolitinib is a safe and effective long-term treatment option for patients with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Taken together, ruxolitinib treatment offers the first widely approved therapeutic alternative for this post-hydroxyurea patient population. Funding: Novartis Pharmaceuticals Corporation

Ruxolitinib versus best available therapy in patients with polycythemia vera: 80-week follow-up from the RESPONSE trial.

RESPONSE is an open-label phase 3 study evaluating the Janus kinase 1/Janus kinase 2 inhibitor ruxolitinib versus best available therapy for efficacy/safety in hydroxyurea-resistant or intolerant patients with polycythemia vera. This preplanned analysis occurred when all patients completed the Week 80 visit or discontinued. Objectives included evaluating the durability of the primary response (Week 32 phlebotomy-independent hematocrit control plus ≥35% spleen volume reduction), its components, and that of complete hematologic remission; and long-term safety. Median exposure was 111 weeks; 91/110 (82.7%) patients randomized to ruxolitinib remained on treatment. No patients continued best available therapy (98/112 [87.5%] crossed over to ruxolitinib, most at/soon after Week 32). At Week 32, primary response was achieved by 22.7% vs. 0.9% of patients randomized to ruxolitinib and best available therapy, respectively (hematocrit control, 60.0% vs. 18.8%; spleen response, 40.0% vs. 0.9%). The probability of maintaining primary and hematocrit responses for ≥80 weeks was 92% and 89%, respectively; 43/44 spleen responses were maintained until Week 80. Complete hematologic remission at Week 32 was achieved in 23.6% of ruxolitinib-randomized patients; the probability of maintaining complete hematologic remission for ≥80 weeks was 69%. Among ruxolitinib crossover patients, 79.2% were not phlebotomized, and 18.8% achieved a ≥35% reduction from baseline in spleen volume after 32 weeks of treatment. New or worsening hematologic laboratory abnormalities in ruxolitinib-treated patients were primarily grade 1/2 decreases in hemoglobin, lymphocytes, and platelets. The thromboembolic event rate per 100 patient-years was 1.8 with randomized ruxolitinib treatment vs. 8.2 with best available therapy. These data support ruxolitinib as an effective long-term treatment option for hydroxyurea-resistant or intolerant patients with polycythemia vera. This trial was registered at clinicaltrials.gov identifier: 01243944.V received funding from and participated in advisory boards for Incyte Corporation. AMV served as a consultant for Novartis, participated in speakers bureaus for Novartis and Shire, and received research funding from Novartis. MG received travel reimbursements from Amgen, Roche, Novartis, and Shire. TM served as a consultant for Novartis and Janssen-Cilag. SD received honoraria and research funding from Novartis. CNH received honoraria from Sanofi, Novartis, and Baxter; served on speakers bureaus for Sanofi, Novartis, Shire, and Baxter; received research funding from Novartis; and received travel reimbursement from Novartis. KK received honoraria from Novartis. CB received honoraria from Novartis and Shire. FPan received honoraria from Novartis, Bristol-Myers Squibb, and Roche; served as a consultant for Bristol Myers Squibb and Ariad; received research funding from Novartis; and received travel reimbursements from Novartis and Roche. BM served on speakers bureaus for Novartis and Bristol-Myers Squibb. CBM received honoraria and served on a speakers bureau and as a consultant for Incyte Corporation. RM received honoraria and served as a consultant for Novartis and received research funding from Incyte Corporation, Gilead, CTI BioPharma, and Celgene. MMJ and HZ are employees and stockholders of Incyte Corporation. JL, NF, and DH are employees and stockholders of Novartis. J-JK served as a consultant for Novartis, Shire, and Incyte Corporation and received research funding from Novartis and AOP Orphan Pharmaceuticals