Drosophila mind bomb2 is required for maintaining muscle integrity and survival

We report that the Drosophila mind bomb2 (mib2) gene is a novel regulator of muscle development. Unlike its paralogue, mib1, zygotic expression of mib2 is restricted to somatic and visceral muscle progenitors, and their respective differentiated musculatures. We demonstrate that in embryos that lack functional Mib2, muscle detachment is observed beginning in mid stage 15 and progresses rapidly, culminating in catastrophic degeneration and loss of most somatic muscles by stage 17. Notably, the degenerating muscles are positive for apoptosis markers, and inhibition of apoptosis in muscles prevents to a significant degree the muscle defects. Rescue experiments with Mib1 and Neuralized show further that these E3 ubiquitin ligases are not capable of ameliorating the muscle mutant phenotype of mib2. Our data suggest strongly that mib2 is involved in a novel Notch- and integrin-independent pathway that maintains the integrity of fully differentiated muscles and prevents their apoptotic degeneration

Targeted cell delivery of mesenchymal stem cell therapy for cardiovascular disease applications: a review of preclinical advancements

Cardiovascular diseases (CVD) continue to be the leading cause of morbidity and mortality globally and claim the lives of over 17 million people annually. Current management of CVD includes risk factor modification and preventative strategies including dietary and lifestyle changes, smoking cessation, medical management of hypertension and cholesterol lipid levels, and even surgical revascularization procedures if needed. Although these strategies have shown therapeutic efficacy in reducing major adverse cardiovascular events such as heart attack, stroke, symptoms of chronic limb-threatening ischemia (CLTI), and major limb amputation significant compliance by patients and caregivers is required and off-target effects from systemic medications can still result in organ dysfunction. Stem cell therapy holds major potential for CVD applications but is limited by the low quantities of cells that are able to traffic to and engraft at diseased tissue sites. New preclinical investigations have been undertaken to modify mesenchymal stem cells (MSCs) to achieve targeted cell delivery after systemic administration. Although previous reviews have focused broadly on the modification of MSCs for numerous local or intracoronary administration strategies, here we review recent preclinical advances related to overcoming challenges imposed by the high velocity and dynamic flow of the circulatory system to specifically deliver MSCs to ischemic cardiac and peripheral tissue sites. Many of these technologies can also be applied for the targeted delivery of other types of therapeutic cells for treating various diseases

Use of defibrotide in COVID-19 pneumonia: comparison of a phase II study and a matched real-world cohort control

The coronavirus disease 2019 (COVID-19) pandemic led to an unprecedented burden on healthcare systems around the world and a severe global socioeconomic crisis, with more than 750 million confirmed cases and at least 7 million deaths reported by 31st December 2023. The DEFI-VID19 study (ClinicalTrials.gov NCT04335201), a phase II, single-arm, multicenter, open-label trial was designed in mid-2020 to assess the safety and efficacy of defibrotide in treating patients with COVID-19 pneumonia. Defibrotide was administered at a dose of 25 mg/kg/d intravenously, divided into four daily doses over a planned 14-day period for patients with COVID-19 pneumonia receiving non-invasive ventilation. The primary endpoint was Respiratory Failure Free Survival (RFFS); Overall Survival (OS), the number of post-recovery days, and adverse events were the secondary endpoints. For comparison, a contemporaneous control cohort receiving standard of care only was retrospectively selected by applying the eligibility criteria of the DEFI-VID19 trial. To adjust for the imbalance between the two cohorts in terms of baseline variable distributions, an outcome regression analysis was conducted. In adjusted analysis, patients receiving defibrotide reported a trend towards higher RFFS (HR=0.71[0.95CI: 0.34 to 1.29, P= .138]) and OS (HR=0.78[0.95CI: 0.33 to 1.53, P= .248]) and showed a significantly increased number of post-recovery days (difference in means: 3.61[ 0.95CI: 0.97 to 6.26, P= .0037]). Despite concomitant thromboprophylaxis with low molecular weight heparin, the safety profile of defibrotide proved to be favorable. Taken together, our findings suggest that defibrotide may represent a valuable addition to the COVID-19 therapeutic options

Loss of L3MBTL1, a Candidate 20q12 Tumor Suppressor Gene, Leads to DNA Damage

Abstract Abstract 1974 Poster Board I-997 The L3MBTL1 gene is located on the long arm of chromosome 20 (q12), a region commonly lost in several myeloid malignancies, including myeloproliferative diseases (MPD), myeloprodysplastic disorders (MDS), and acute myeloid leukemias (AML). MDS and AML frequently have complex cytogenetic profiles, and are thought to arise due to accumulation of several cooperating mutations. We have previously reported that L3MBTL1 is highly expressed in human hematopoietic progenitor cells. L3MBTL1 is a homolog of Drosophila polycomb L3MBTL tumor suppressor protein. Thus, L3MBTL1 is a candidate gene in 20q12 myeloid disorders. We have depleted L3MBTL1 by RNAi in several human cell lines, and find that loss of L3MBTL1 leads to a decrease of cells in the S phase of the cell cycle and accumulation in G2/M phase. Cells with depleted L3MBTL1 have an increase of spontaneous DNA breaks, as evidenced by accumulation of γH2A.X foci and comet assay. The presence of DNA breaks leads to activation of DNA damage response, as the L3MBTL1 knockdown cells have increased levels of phosphoChk1 (Ser317 and Ser345), phosphoChk2 (Thr68), phosphoATM (Ser1981), p21 and p53. The DNA damage in the L3MBTL1-depleted cells activates DNA repair machinery, as shown by the increase in Rad51 levels. We propose that the spontaneous DNA damage caused by depletion of L3MBTL1 could contribute to the development of 20q12 myeloid malignancies. Disclosures: No relevant conflicts of interest to declare

Mesenchymal stem cell-based therapy for non-healing wounds due to chronic limb-threatening ischemia: A review of preclinical and clinical studies

Progressive peripheral arterial disease (PAD) can result in chronic limb-threatening ischemia (CLTI) characterized by clinical complications including rest pain, gangrene and tissue loss. These complications can propagate even more precipitously in the setting of common concomitant diseases in patients with CLTI such as diabetes mellitus (DM). CLTI ulcers are cutaneous, non-healing wounds that persist due to the reduced perfusion and dysfunctional neovascularization associated with severe PAD. Existing therapies for CLTI are primarily limited to anatomic revascularization and medical management of contributing factors such as atherosclerosis and glycemic control. However, many patients fail these treatment strategies and are considered "no-option," thereby requiring extremity amputation, particularly if non-healing wounds become infected or fulminant gangrene develops. Given the high economic burden imposed on patients, decreased quality of life, and poor survival of no-option CLTI patients, regenerative therapies aimed at neovascularization to improve wound healing and limb salvage hold significant promise. Cell-based therapy, specifically utilizing mesenchymal stem/stromal cells (MSCs), is one such regenerative strategy to stimulate therapeutic angiogenesis and tissue regeneration. Although previous reviews have focused primarily on revascularization outcomes after MSC treatments of CLTI with less attention given to their effects on wound healing, here we review advances in pre-clinical and clinical studies related to specific effects of MSC-based therapeutics upon ischemic non-healing wounds associated with CLTI

Abstract 3032: Novel GLP-Grade E-Selectin/AAV2 Gene Therapy Optimal Dosage For Vascular Regeneration

Abstract only Introduction: Chronic Limb Threatening Ischemia (CLTI) represents a major public health burden with with an estimated 15 to 20% CLTI patients undergoing major limb amputation facing a 50% mortality risk at 5 years post amputation. We previously demonstrated the pro-angiogenic actions of a research-grade E-Selectin/AAV gene therapy in a hindlimb gangrene murine model. In this study, a dosage study utilizing GLP grade codon-optimized and DeNovo-synthesized E-selectin/AAV2 was conducted dosage optimization and determination of the necessary scale-up for subsequent clinical trials. Methods: codon-optimized and de novo synthesized human and murine E-selectin AAV vectors under GLP conditions was evaluated in vitro by cell transduction assays. E-selectin/AAV2 i.m. injection in three cohorts of FVB/NJ mice (9-12 weeks old, N=6/group) with GFP/AAV2 (9-12 weeks old, N=6/group) groups, was performed in vivo in escalating log doses ranging from 2x10^9 VG to 2x10^11 VG. Hindlimb ischemia and gangrene were subsequently induced through left femoral artery/vein ligation/excision (FAVLE). Limb perfusion recovery and function was assessed postoperatively by Laser Doppler Imaging (LDI), Faber hindlimb ischemia scores, treadmill exhaustion test, whole-body Dil perfusion Results: Treatment with high dose (2x10^11 VG) of E-selectin/AAV2 significantly improve perfusion indices compared to control groups (p=.0019, N=6/group) and lower doses (p=.0006 and p=.0082, N=6/group) with decreased Faber’s scores. A significant increase in neovascularization was also observed compared to GFP control (0.41 ±0.14 to 0.95±0.18; p=.0080, N=5/group) and lower doses (p=.0026 and p=.009, N=5/group). Running stamina was also significantly improve by VRGT with a 2x10^11 VG dosage treatment compared to GFP (p=0.0047) control and lower doses, establishing a clear dose-dependent response. Conclusion: VGRT improves recovery of ischemic hindlimb perfusion and function at an optimal dose of 2x10 11 VG. This pre-clinical study paves the way towards further studies using the same AAV construct manufactured under cGMP conditions and subsequent Investigational New Drug (IND) process for clinical pilot studies and disease burden relief