The developmental and evolutionary characteristics of transcription factor binding site clustered regions based on an explainable machine learning model.

Gene expression is temporally and spatially regulated by the interaction of transcription factors (TFs) and cis-regulatory elements (CREs). The uneven distribution of TF binding sites across the genome poses challenges in understanding how this distribution evolves to regulate spatio-temporal gene expression and consequent heritable phenotypic variation. In this study, chromatin accessibility profiles and gene expression profiles were collected from several species including mammals (human, mouse, bovine), fish (zebrafish and medaka), and chicken. Transcription factor binding sites clustered regions (TFCRs) at different embryonic stages were characterized to investigate regulatory evolution. The study revealed dynamic changes in TFCR distribution during embryonic development and species evolution. The synchronization between TFCR complexity and gene expression was assessed across species using RegulatoryScore. Additionally, an explainable machine learning model highlighted the importance of the distance between TFCR and promoter in the coordinated regulation of TFCRs on gene expression. Our results revealed the developmental and evolutionary dynamics of TFCRs during embryonic development from fish, chicken to mammals. These data provide valuable resources for exploring the relationship between transcriptional regulation and phenotypic differences during embryonic development.

Sequential administration of delta-tocotrienol ameliorates radiation-induced myelosuppression in mice and non-human primates through inducing G-CSF production.

To date only four recombinant growth factors, including Filgrastim (rhG-CSF), have been approved by FDA as radiomitigators to ameliorate hematopoietic acute radiation syndrome (H-ARS). These approved agents are not stable under room-temperature, needing to be stored at 2-8 °C, and would not be feasible in a mass casualty scenario where rapid and cost-effective intervention is crucial. Delta-tocotrienol (δ-T3H), the most potent G-CSF-inducing agent among vitamin E isoforms, exhibited efficiency and selectivity on G-CSF production in comparison with TLR and STING agonists in mice. Five-dose δ-T3H was utilized as the optimal therapeutic regimen due to long-term G-CSF production and the best peripheral blood (PB) recovery of irradiated mice. Comparable with rhG-CSF, sequential administration of δ-T3H post-irradiation improved hematologic recovery and accelerated the regeneration of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) in the bone marrow (BM) and spleen of 6.5Gy irradiated mice; and consistently enhanced repopulation of BM-HSCs. In 4.0Gy irradiated nonhuman primates, δ-T3H exhibited comparable efficacy as rhG-CSF to promote PB recovery and colony-formation of BM-HPCs. Altogether, we demonstrated that sequential administration of delta-tocotrienol ameliorates radiation-induced myelosuppression in mice and non-human primates through inducing G-CSF production, indicated δ-T3H as a promising radiomitigator for the management of H-ARS, particularly in a mass casualty scenario.

Fluacrypyrim Protects Hematopoietic Stem and Progenitor Cells against Irradiation via Apoptosis Prevention.

Ionizing radiation (IR)-induced hematopoietic injury has become a global concern in the past decade. The underlying cause of this condition is a compromised hematopoietic reserve, and this kind of hematopoietic injury could result in infection or bleeding, in addition to lethal mishaps. Therefore, developing an effective treatment for this condition is imperative. Fluacrypyrim (FAPM) is a recognized effective inhibitor of STAT3, which exhibits anti-inflammation and anti-tumor effects in hematopoietic disorders. In this context, the present study aimed to determine whether FAPM could serve as a curative agent in hematopoietic-acute radiation syndrome (H-ARS) after total body irradiation (TBI). The results revealed that the peritoneally injection of FAPM could effectively promote mice survival after lethal dose irradiation. In addition, promising recovery of peripheral blood, bone marrow (BM) cell counts, hematopoietic stem cell (HSC) cellularity, BM colony-forming ability, and HSC reconstituting ability upon FAPM treatment after sublethal dose irradiation was noted. Furthermore, FAPM could reduce IR-induced apoptosis in hematopoietic stem and progenitor cells (HSPCs) both in vitro and in vivo. Specifically, FAPM could downregulate the expressions of p53-PUMA pathway target genes, such as Puma, Bax, and Noxa. These results suggested that FAPM played a protective role in IR-induced hematopoietic damage and that the possible underlying mechanism was the modulation of apoptotic activities in HSCs.

Radioprotective effectiveness of a novel delta-tocotrienol prodrug on mouse hematopoietic system against 60Co gamma-ray irradiation through inducing granulocyte-colony stimulating factor production.

Considering the increasing risk of nuclear attacks worldwide, the development of develop potent and safe radioprotective agents for nuclear emergencies is urgently needed. γ-tocotrienol (GT3) and δ-tocotrienol (DT3) have demonstrated a potent radioprotective effect by inducing the production of granulocyte-colony stimulating factor (G-CSF) in vivo. However, their application is limited because of their low bioavailability. The utilization of ester prodrugs can be an effective strategy for modifying the pharmacokinetic properties of drug molecules. In this study, we initially confirmed that DT3 exhibited the most significant potential for inducing G-CSF effects among eight natural vitamin E homologs. Consequently, we designed and synthesized a series of DT3 ester and ether derivatives, leading to improved radioprotective effects. The metabolic study conducted in vitro and in vivo has identified DT3 succinate 5b as a prodrug of DT3 with an approximately seven-fold higher bioavailability compared to DT3 alone. And DT3 ether derivative 8a were relatively stable and approximately 4 times more bioavailable than DT3 prototype. Furthermore, 5b exhibited superior ability to mitigate radiation-induced pancytopenia, enhance the recovery of bone marrow hematopoietic stem and progenitor cells, and promote splenic extramedullary hematopoiesis in sublethal irradiated mice. Similarly, 8a shown potential radiation protection, but its radiation protection is less than DT3. Based on these findings, we identified 5b as a DT3 prodrug, and providing an attractive candidate for further drug development.

Single-dose Administration of Recombinant Human Thrombopoietin Enhances Survival and Hematopoietic Reconstruction in Canines Irradiated with 3 Gy Gamma Radiation.

We conducted this study to investigate the radioprotective effects of recombinant human thrombopoietin (rhTPO) on beagle dogs irradiated with 3.0 Gy 60Co gamma rays. Fifteen healthy adult beagles were randomly assigned to a control group with alleviating care, and 5 and 10 µg/kg rhTPO treatment group. All animals received total-body irradiation using 60Co γ-ray source at a dose of 3.0 Gy (dose rate was 69.1 cGy/min). The treatment group received intramuscular injection of rhTPO 5 and 10 µg/kg at 2 h postirradiation, and the control group was administrated the same volume of normal saline. The survival rate, clinical signs, peripheral hemogram, serum biochemistry, and histopathological examination of animals in each group were assessed. Single administration of 10 µg/kg rhTPO at 2 h postirradiation promoted the recovery of multilineage hematopoiesis and improved the survival rate of beagles irradiated with 3 Gy 60Co γ rays. The administration of 10 µg/kg rhTPO alleviated fever and bleeding, reduced the requirement for supportive care, and may have mitigated multiple organ damage.