Apoptosis Of Bone Marrow Cells Research Articles

HSPA9/mortalin inhibition disrupts erythroid maturation through a TP53-dependent mechanism in human CD34+ hematopoietic progenitor cells.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic stem cell malignancies characterized by abnormal hematopoietic cell maturation, increased apoptosis of bone marrow cells, and anemia. They are the most common myeloid blood cancers in American adults. The full complement of gene mutations that contribute to the phenotypes or clinical symptoms in MDS is not fully understood. Around 10%-25% of MDS patients harbor an interstitial heterozygous deletion on the long arm of chromosome 5 [del(5q)], creating haploinsufficiency for a large set of genes, including HSPA9. The HSPA9 gene encodes for the protein mortalin, a highly conserved heat shock protein predominantly localized in mitochondria. Our prior study showed that knockdown of HSPA9 induces TP53-dependent apoptosis in human CD34+hematopoietic progenitor cells. In this study, we explored the role of HSPA9 in regulating erythroid maturation using human CD34+cells. We inhibited the expression of HSPA9 using gene knockdown and pharmacological inhibition and found that inhibition of HSPA9 disrupted erythroid maturation as well as increased expression of p53 in CD34+cells. To test whether the molecular mechanism of HSPA9 regulating erythroid maturation is TP53-dependent, we knocked downHSPA9 and TP53 individually or in combination in human CD34+cells. We found that the knockdown of TP53 partially rescued the erythroid maturation defect induced by HSPA9 knockdown, suggesting that the defect in cells with reduced HSPA9 expression is TP53-dependent. Collectively, these findings indicate that reduced levels of HSPA9 may contribute to the anemia observed in del(5q)-associated MDS patients due to the activation of TP53.

Abstract 248: HSPA9/mortalin regulates erythroid maturation through a TP53-dependent mechanism in human CD34+ hematopoietic progenitor cells

Abstract Mortalin, encoded by the HSPA9 gene, is a highly conserved heat-shock chaperone belonging to the HSP70 family. It is predominantly presented in the mitochondria, and is critical in regulating a variety of cell physiological functions such as response to cell stress, control of cell proliferation, and inhibition/prevention of apoptosis. Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell malignancies characterized by ineffective hematopoiesis, increased apoptosis of bone marrow cells, and anemia. Up to 25% of MDS patients harbor an interstitial deletion on the long arm of chromosome 5, also known as del(5q), creating haploinsufficiency for multiple genes including HSPA9. Our prior study showed that knockdown of HSPA9 induces TP53-dependent apoptosis in human CD34+ hematopoietic progenitor cells, consistent with cytopenia observed in MDS patients. Since anemia is another featured symptom of MDS, we hypothesize that HSPA9 plays a role in regulating erythroid maturation. To test our hypothesis, we inhibited the expression of HSPA9 using various methods and measured the erythroid maturation in human CD34+ cells. We used siRNA targeting HSPA9 and found that HSPA9 siRNA significantly inhibited the cell growth, increased cell apoptosis, inhibited erythroid maturation (using CD71 as a surrogate marker), and increased p53 expression (p<0.01) compared to control siRNA in human CD34+ cells. Pharmacologic inhibition of HSPA9 by the chemical MKT-077, an inhibitor of HSP70 protein family members including mortalin, also increased p53 expression and inhibited erythroid maturation in human CD34+ cells. In addition, knockdown of HSPA9 by shRNA showed significant inhibition of erythroid maturation in human CD34+ cells compared to control shRNA. In order to test whether the regulation of erythroid maturation by HSPA9 is TP53-dependent or not, we constructed shRNAs targeting TP53 genes and simultaneously transduced lentivirus containing shRNAs targeting HSPA9 and TP53 respectively in human CD34+ cells using double antibiotics selection (puromycin for shRNA targeting HSPA9 and hygromycin for shRNA targeting TP53). We found that TP53 knockdown partially rescued the erythroid maturation defect caused by HSPA9 inhibition, suggesting that erythroid maturation inhibition by HSPA9 knockdown is partly mediated through a TP53 mechanism. Collectively, our results suggest that the increased apoptosis and reduced erythroid maturation observed in del(5a)-associated MDS is TP53-dependent. HSPA9/mortalin may be a potential target to treat anemia in del(5q) MDS patients, although simultaneous loss of multiple genes on del(5q) likely contributes to the complex phenotypes observed in MDS. Thus, our study not only uncovers some underlying mechanisms of del(5q) MDS, but also provides potential therapeutic indications through gene targeting in clinical MDS treatment. Citation Format: Tuoen Liu, Christopher Butler, Morgan Dunmire, Gabor Szalai, Anissa Johnson, Jaebok Choi, Matthew Walter. HSPA9/mortalin regulates erythroid maturation through a TP53-dependent mechanism in human CD34+ hematopoietic progenitor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 248.

Abstract 5701: AU2-94: A CDK4-specific inhibitor with the marked anti-tumor efficacy

Abstract Cyclin-dependent kinases (CDKs) are a vital family of proteins in the cell development. Several CDK4/6 inhibitor drugs significantly extended the lives of subtypes breast cancer patients. However, they have some shortcomings. Many patients do not respond to them well mainly due to off-target toxicity requiring dose reductions and treatment interruptions, and thus building resistance, which limit their effectiveness. Here, we describe AU2-94, a highly selective CDK4 inhibitor, for the treatment of CDK4-dependent tumours including breast cancer (ER+ and TNBC), colorectal cancer and glioblastoma (GBM). AU2-94 exhibits high selectivity for CDK4 (Ki = 2 nM) over CDK6 (Ki = 279 nM). Consistent with the CDK4-targeted mechanism, AU2-94 arrested the G1 cells and inhibited cancer cell proliferation. Interestingly, AU2-94 reduced cellular CDK2, Cyclin E2, Cyclin A2, Cyclin B1, and induced apoptosis via reduction of Bcl-2, FOXM1 etc. In contrast to cancer cells, AU2-94 has little impact on the cell cycle, senescence, or apoptosis of human bone marrow cells, whereas the known CDK4/6 inhibitors increased the G1 cells. AU2-94 showed little or no effect on lymphocyte and neutrophil counts whilst the clinical CDK4/6 inhibitors reduced them. This lower effect of AU2-94 on the bone marrow, neutrophils and lymphocytes might be due to its lesser effect on CDK6 compared to the clinical CDK4/6 inhibitors. AU2-94 was highly efficacious against multiple in vivo tumour models. In the ER+ breast cancer T47D xenografts, AU2-94 caused tumour regression. In the model of MDA-MB-453 AR+ luminal breast cancer (CDK4, KRASmut, PI3KCAmut), AU2-94 demonstrated remarkable efficacy, resulting in the 6 out of 7 (86%) mice tumour-free. In the colorectal cancer HCT116 (CDK4/6, KRASmut) xenografts, AU2-94 inhibited tumour growth markedly in a dose-dependent manner from 25 to 200 mg/kg without any overt toxicity. The pharmacokinetic and pharmacodynamic study revealed up to 500-fold higher concentration of AU2-94 in the tumours than in the plasma, suggesting its tumour targeting specificity. Several robust biomarkers/PD markers were identified. The Rb-CDK4-Cyclin D pathway is altered in the majority of GBM due to homozygous deletion of CDKN2A/B. AU2-94 has an excellent therapeutic potential as it crossed the blood-brain-barrier effectively. In the both U87 subcutaneous and orthotopic models, AU2-94 reduced the tumour burden and increased the survival of GBM bearing mice significantly compared to vehicle. Moreover, AU2-94 synergised the anti-cancer efficacy of PI3K/Akt/mTOR and HER2 inhibitors in combination. In summary, AU2-94 is a CDK4 inhibitor with high selectivity against a panel of 360 human kinases. This selectivity can be a reason for the better safety of AU2-94 compared to the clinical CDK4/6 inhibitors. The high oral bioavailability, robust antitumor efficacy and excellent safety profiles make AU2-94 a highly attractive candidate for clinical development. Citation Format: Laychiluh Bantie, Jimma Likisa, Muhammed Rahaman, Theodosia Teo, Ava Safaroghliazar, Sunita KC Basnet, Ramin Hassankhani, Benjamin Noll, Robert Milne, Shudong Wang. AU2-94: A CDK4-specific inhibitor with the marked anti-tumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5701.

Stereotactic body radiation therapy suppresses myeloid-derived suppressor cells by regulating miR-21/Sorbin and SH3 Domain-containing Protein 1 axis.

Stereotactic body radiation therapy (SBRT) is a targeted form of radiotherapy used to treat early-stage cancers. Despite its effectiveness, the impact of SBRT on myeloid-derived suppressor cells (MDSCs) is not well understood. In this study, we examined how SBRT affects the differentiation and survival of MDSCs, as well as delved into the molecular mechanisms involved. SBRT was utilized on bone marrow (BM)-derived MDSCs to investigate its impact on the differentiation and survival of MDSCs using flow cytometry. An animal model of lung cancer was created to assess the anti-cancer properties of SBRT and the role of miR-21 expression in MDSCs. The interplay of miR-21 and Sorbin and SH3 domain-containing protein 1 (SORBS1) in MDSC differentiation was explored through dual luciferase activity assay, RT-qPCR, and Western blot analysis. The findings suggest that SBRT led to an increase in miR-21 levels, inhibited MDSC differentiation, and triggered cell apoptosis in BM cells. Inhibition of miR-21 reversed the effects of SBRT on MDSC differentiation and apoptosis. Additionally, it was revealed that SORBS1 was a downstream target of miR-21 in BM cells, and the miR-21/SORBS1 axis played a role in regulating MDSC differentiation and apoptosis induced by SBRT. Modulating miR-21 levels in vivo impinged on the response to SBRT treatment and the quantity of MDSCs in a mouse model of lung cancer. Our data indicate that the upregulation of miR-21 induced by SBRT may contribute to the inhibition of MDSC expansion in a lung cancer model.

Integration of Network Pharmacology and Experimental Validation to Explore Jixueteng - Yinyanghuo Herb Pair Alleviate Cisplatin-Induced Myelosuppression.

Jixueteng, the vine of the bush Spatholobus suberectus Dunn., is widely used to treat irregular menstruation and arthralgia. Yinyanghuo, the aboveground part of the plant Epimedium brevicornum Maxim., has the function of warming the kidney to invigorate yang. This research aimed to investigate the effects and mechanisms of the Jixueteng and Yinyanghuo herbal pair (JYHP) on cisplatin-induced myelosuppression in a mice model. Firstly, ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) screened 15 effective compounds of JYHP decoction. Network pharmacology enriched 10 genes which may play a role by inhibiting the apoptosis of bone marrow (BM) cells. Then, a myelosuppression C57BL/6 mice model was induced by intraperitoneal (i.p.) injection of cis-Diaminodichloroplatinum (cisplatin, CDDP) and followed by the intragastric (i.g.) administration of JYHP decoction. The efficacy was evaluated by blood cell count, reticulocyte count, and histopathological analysis of bone marrow and spleen. Through the vivo experiments, we found the timing of JYHP administration affected the effect of drug administration, JYHP had a better therapeutical effect rather than a preventive effect. JYHP obviously recovered the hematopoietic function of bone marrow from the peripheral blood cell test and pathological staining. Flow cytometry data showed JYHP decreased the apoptosis rate of BM cells and the western blotting showed JYHP downregulated the cleaved Caspase-3/Caspase-3 ratios through RAS/MEK/ERK pathway. In conclusion, JYHP alleviated CDDP-induced myelosuppression by inhibiting the apoptosis of BM cells through RAS/MEK/ERK pathway and the optimal timing of JYHP administration was after CDDP administration.

Study on the combined toxicity of DEHP and lead on the blood system of rats

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used phthalate ester compound, while lead is a persistent and bioaccumulative heavy metal. Both can be exposed to the body through a variety of ways, which may have an impact on the blood system. In this study, we examined the impact of co-exposure to DEHP (0, 10, 100 mg/kg) and Pb (0, 5, 50 mg/kg) on the blood system of male SD rats. The study revealed that continuous exposure to DEHP and Pb for 20 days resulted in a decrease in leukocytes and lymphocytes, while an increase in neutrophils and monocytes. Co-exposure led to a significant decrease in the spleen coefficients. Furthermore, the combined exposure could increase the ratio of bone marrow cells in G1 phase, and decrease the ratio of cells in S phase and G2 phase. Cytokine testing showed that combined exposure affects the secretion of hematopoietic factors and may cause bone marrow cell apoptosis. Single or combined exposure to DEHP and Pb can cause oxidative stress in serum and bone marrow. Overall, these results indicate that the co-exposure of DEHP and Pb adversely affected the blood system of rats, mainly due to the induction of oxidative stress and ultimately affects the secretion of cytokines. The combined effect of the two substances is primarily antagonistic. These results have important implications for the risk assessment of combined pollution and provide valuable theoretical guidance.

Silencing of peroxiredoxin III inhibits formaldehyde-induced oxidative damage of bone marrow cells in BALB/c mice.

Formaldehyde (FA) is associated with the occurrence of leukemia, and oxidative stress is considered to be a major reason. As an endogenous biomarker of oxidative stress, few studies focus on the relationship between peroxiredoxin III (PrxIII) and FA toxicity. Our previous research observed high expression of PrxIII occurred in the process of apoptosis of bone marrow cells (BMCs) induced by FA, however the exact mechanism is unclear. Therefore, this paper aimed to explore the possible association between FA toxicity and PrxIII gene. We first, used a Cell Counting Kit-8 (CCK-8) to detect the viability of BMCs after they were exposed to different doses of FA (50, 100, 200 μmol/L) for different exposure time (12, 24, 48 h), then chose 24 h as an exposure time to detect the expression of PrxIII for exposing different doses of FA by Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analysis. Based on our preliminary experimental results, we chose 100 μmol/L FA as an exposure dose to expose for 24 h, and used a small interfering RNA (siRNA) to silenced PrxIII to examine the cell viability by CCK-8, reactive oxygen species (ROS) level by DCFH-DA, apoptosis by Annexin V/PI double staining and cell cycle by flow cytometry (FCM) so as to explore the possible regulatory effect of PrxIII silencing on FA-induced bone marrow toxicity. High expression of PrxIII occurred in the process of FA-induced oxidative stress. Silencing of PrxIII prevented FA from inducing oxidative stress, thus increasing cell viability, decreasing ROS level, rescuing G0 -G1 and G2 -M arrest, and reducing cell apoptosis. PrxIII silencing might be a potential target for alleviating FA-induced oxidative damage.

The effect of platelet infusion on the repair of bone marrow hematopoietic niche damage in mice induced by (60)Co radiation and hematopoietic reconstruction after bone marrow transplantation

Objective: To observe the effect of platelets on hematopoietic stem cell (HSCs) implantation in mice with radiation-induced bone marrow injury and bone marrow transplantation models. Methods: ①Male C57BL/6 mice were divided into a single irradiation group and a radiation infusion group after receiving (60)Co semimyeloablative irradiation for 18-10 weeks. The irradiation infusion group received 1×10(8) platelets expressing GFP fluorescent protein. ② The allogeneic bone marrow transplantation model was established. The experimental groups included the simple transplantation group (BMT) and the transplantation infusion group (BMT+PLT). The BMT group was infused through the tail vein only 5 × 10(6) bone marrow cells, the BMT+PLT group needs to be infused with bone marrow cells at the same time 1× 10(8) platelets. ③ Test indicators included peripheral blood cell and bone marrow cell counts, flow cytometry to detect the proportion of hematopoietic stem cell (HSC) and hematopoietic progenitor cells, bone marrow cell proliferation and apoptosis, and pathological observation of vascular niche damage and repair. Results: ①On the 3rd, 7th, 14(th), and 21st days after irradiation, the bone marrow cell count of the infusion group was higher than that in the single irradiation group (P<0.05), and the peripheral blood cell count was also higher. A statistically significant difference was found between the white blood cell count on the 21st day and the platelet count on the 7th day (P<0.05). In the observation cycle, the percentage of bone marrow cell proliferation in the infusion group was higher, while the percentage of apoptosis was lower. ② The results of bone tissue immunofluorescence after irradiation showed that the continuity of hematopoietic niche with red fluorescence was better in the irradiation infusion group. ③The chimerism percentage in the BMT+PLT group was always higher than that in the BMT group after transplantation.④ The BMT+PLT group had higher bone marrow cell count and percentage of bone marrow cell proliferation on the 7th and 28th day after transplantation than that in the BMT group, and the percentage of bone marrow cell apoptosis on the 14th day was lower than that in the BMT group (P<0.05). After the 14th day, the percentage of stem progenitor cells in the bone marrow cells of mice was higher than that in the BMT group (P<0.05). ⑤The immunohistochemical results of bone marrow tissue showed that the continuity of vascular endothelium in the BMT+PLT group was better than that in the BMT group. Conclusion: Platelet transfusion can alleviate the injury of vascular niche, promotes HSC homing, and is beneficial to hematopoietic reconstruction.

Effects on hematopoietic and immune system of ultra-high dose rate radiotherapy (FLASH-RT).

166 Background: Ultra-high dose rate radiotherapy, so-called FLASH radiotherapy (FLASH-RT) has shown to reduce radiation-induced damage including lung fibrosis, brain damage, skin fibrosis, etc. We investigated the effect of FLASH-RT compared of conventional dose rate radiotherapy (CONV-RT) at 5Gy of TBI on survival of hematopoietic system, peripheral blood cells, and immune-related responses. Methods: Mice were divided into 3 groups: control (0 Gy), FLASH-RT (109Gy/s), and CONV-RT (0.067Gy/s). FLASH-RT was performed with DIRAMS LINAC producing 6 MeV electron beams. Irradiated mice were sacrificed at 1, 2, 4, 7, 14, 21 and 28 post-TBI of 5 Gy and cellularity of peripheral blood and bone marrow, histological evaluation of immune organ such as spleen and thymus, and T and B lymphocytes in mouse spleen by flow cytometry were investigated. Results: In peripheral blood cell counts, RBC, neutrophil, lymphocyte counts were not significantly different between FLASH-RT and CONV-RT groups from day 1 to day 28 post-TBI. However, FLASH-RT initially induced more apoptosis of bone marrow cells, platelets, and eosinophils of peripheral blood compared to CONV-RT. FLASH-RT and CONV-RT groups showed similar histological changes in the thymus and spleen after 5Gy of TBI, but T lymphocytes of CONV-RT group in day 28 were less recovered compared to those of FLASH-RT group. Our results indicated that FLASH-RT affected more radiation-induced damage of hematopoietic system in early stages compared to CONV-RT, but FLASH-RT showed higher recovery of T lymphocytes after irradiation. Conclusions: These results show that FLASH-RT can induce similar damage and recovery pattern on hematopoietic system with CONV-RT in first week, but FLASH-RT might affect less T-lymphopenia in long-term than CONV-RT.

Endogenous production of ω-3 polyunsaturated fatty acids mitigates cisplatin-induced myelosuppression by regulating NRF2-MDM2-p53 signaling pathway.

Cisplatin is a chemotherapy medication used to treat a wide range of cancers. A common side effect of cisplatin is myelosuppression. Research suggests that oxidative damages are strongly and consistently related to myelosuppression during cisplatin treatment. ω-3 polyunsaturated fatty acids (PUFAs) can enhance the antioxidant capacity of cells. Herein, we investigated the protective benefit of endogenous ω-3 PUFAs on cisplatin-induced myelosuppression and the underlying signaling pathways using a transgenic mfat-1 mouse model. The expression of mfat-1 gene can increase endogenous levels of ω-3 PUFAs by enzymatically converting ω-6 PUFAs. Cisplatin treatment reduced peripheral blood cells and bone marrow nucleated cells, induced DNA damage, increased the production of reactive oxygen species, and activated p53-mediated apoptosis in bone marrow (BM) cells of wild-type mice. In the transgenics, the elevated tissue ω-3 PUFAs rendered a robust preventative effect on these cisplatin-induced damages. Importantly, we identified that the activation of NRF2 by ω-3 PUFAs could trigger an antioxidant response and inhibit p53-mediated apoptosis by increasing the expression of MDM2 in BM cells. Thus, endogenous ω-3 PUFAs enrichment can strongly prevent cisplatin-induced myelosuppression by inhibiting oxidative damage and regulating the NRF2-MDM2-p53 signaling pathway. Elevation of tissue ω-3 PUFAs may represent a promising treatment strategy to prevent the side effects of cisplatin.

Heterogalactan WPEP-N-b from Pleurotus eryngii enhances immunity in immunocompromised mice

This study reports on in vivo immunomodulatory activities mediated by WPEP-N-b, a heterogalactan from Pleurotus eryngii. Using cyclophosphamide (CTX)–induced immunosuppressed mice, we demonstrate here that WPEP-N-b enhances immunity as determined by the immune organ index, peripheral blood immune cell content, splenocyte proliferation, NK cell activity and T lymphocyte subpopulations. WPEP-N-b prevented apoptosis of bone marrow cells induced by CTX. The level of cytokines (i.e. TNF-α, IL-6 and IL-1β) and macrophage activity in these immunocompromised mice were restored upon treated with WPEP-N-b. Mechanistically, it appears that WPEP-N-b enhances splenocyte proliferation and NK cell activity might through the Toll-like receptor 4 (TLR4)-PKC signaling axis, and increases macrophage activity by activating JNK, p38 and NF-κB signaling pathways and Toll-like receptor 2 (TLR2) is the possible receptor of WPEP-N-b in macrophages. Our findings indicate that WPEP-N-b may function as a natural immune stimulant.

Dioscin Regulating Bone Marrow Apoptosis in Aplastic Anemia.

BackgroundAplastic anemia (AA), a disease of bone marrow failure, is caused by CD8+T mediated apoptosis of hematopoietic cells. However, traditional immunosuppressive therapy (IST) has severe liver and kidney toxicity and even cannot achieve the expected therapeutic effect in some patients.PurposeOur study is aimed to investigate the effect and mechanism of dioscin (DNS) for treating AA.MethodsBriefly, we established and evaluated the AA mouse model, DNS and positive control drugs were used for intervention treatment. After 14 days of intervention, femoral bone marrow pathology, bone marrow mononuclear cells (BMMCs) apoptosis rate, bone marrow CD34+ cell surface Fas (CD95) expression and Fas signaling pathway key proteins were detected.ResultsAfter the establishment of the AA mouse model, the number of peripheral blood cells including granulocytes, erythrocytes, hemoglobin, platelets and reticulocytes in the AA group model was significantly decreased compared with the group control (P < 0.01). The degree of bone marrow hyperplasia in the sternum and femur is extremely low. After different drug interventions, compared with the group model, the number of peripheral blood cells in the AA mice rebounded significantly in group DNS (P < 0.01). Not only that the apoptosis rate of BM-MCs decreased (P < 0.01), meanwhile, the CD95 molecule expressed on the CD34+ bone marrow cells had a significant decline (P < 0.01), and the expression level of the key proteins of Fas signaling pathway was also significantly decreased (P < 0.01).ConclusionDNS recovered the peripheral pancytopenia and bone marrow failure in AA mice. DNS reduced the key protein of Fas signaling pathway level to inhibit apoptosis of bone marrow cells to treat AA.

UHPLC/MS-Based Serum Metabolomics Reveals the Mechanism of Radiation-Induced Thrombocytopenia in Mice.

Radiation-induced thrombocytopenia is a common and life-threatening side effect of ionizing radiation (IR) therapy. However, the underlying pathological mechanisms remain unclear. In the present study, irradiation was demonstrated to significantly reduce platelet levels, inhibit megakaryocyte differentiation, and promote the apoptosis of bone marrow (BM) cells. A metabolomics approach and a UHPLC-QTOF MS system were subsequently employed for the comprehensive analysis of serum metabolic profiles of normal and irradiated mice. A total of 66 metabolites were significantly altered, of which 56 were up-regulated and 10 were down-regulated in irradiated mice compared to normal mice on day 11 after irradiation. Pathway analysis revealed that disorders in glycerophospholipid metabolism, nicotinate and nicotinamide metabolism, sphingolipid metabolism, inositol phosphate metabolism, and tryptophan metabolism were involved in radiation-induced thrombocytopenia. In addition, three important differential metabolites, namely L-tryptophan, LysoPC (17:0), and D-sphinganine, which were up-regulated in irradiated mice, significantly induced the apoptosis of K562 cells. L-tryptophan inhibited megakaryocyte differentiation of K562 cells. Finally, serum metabolomics was performed on day 30 (i.e., when the platelet levels in irradiated mice recovered to normal levels). The contents of L-tryptophan, LysoPC (17:0), and D-sphinganine in normal and irradiated mice did not significantly differ on day 30 after irradiation. In conclusion, radiation can cause metabolic disorders, which are highly correlated with the apoptosis of hematopoietic cells and inhibition of megakaryocyte differentiation, ultimately resulting in thrombocytopenia. Further, the metabolites, L-tryptophan, LysoPC (17:0), and D-sphinganine can serve as biomarkers for radiation-induced thrombocytopenia.

Two birds with one stone: YQSSF regulates both proliferation and apoptosis of bone marrow cells to relieve chemotherapy-induced myelosuppression

Ethnopharmacological relevanceYiqi Shengsui formula (YQSSF) is a commonly used formula to treat chemotherapy-induced myelosuppression, but little is known about its therapeutic mechanisms. Aim of this studyThis study aims to examine the effect of YQSSF in treating myelosuppression and explore its mechanism. Materials and methodsA myelosuppression BALB/c mouse model was established by intraperitoneal (i.p.) injection of cyclophosphamide (CTX). The efficacy of YQSSF in alleviating chemotherapy-induced myelosuppression was evaluated by blood cell count, immune organ (thymus, spleen, liver) index, bone marrow nucleated cell (BMNC) count and histopathological analysis of bone marrow and spleen. Then, ultra-performance liquid chromatograph quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was performed to analyze the ingredients of YQSSF extract. Key effects and potential mechanism of YQSSF extract in alleviating myelosuppression were predicted by network pharmacology method. Finally, cell cycle and TUNEL staining of bone marrow cells was detected to verify the key effects, and RT-qPCR or Western blotting were performed to measure the gene and protein expressions of the effect targets respectively to confirm the predicted mechanism of YQSSF for myelosuppression. ResultsYQSSF up-regulated the number of peripheral blood leukocytes and BMNC, reduced spleen index and liver index, improved the pathological morphology of bone marrow and spleen. A total of 40 ingredients were isolated from YQSSF extract using UPLC-Q/TOF-MS analysis. Network pharmacology revealed that YQSSF regulated both proliferation and apoptosis to alleviate myelosuppression. Finally, YQSSF decreased G0/G1 ratio, increased the proportion of bone marrow cells in S phase and proliferation index (PI), and reduced apoptotic cells in femur bone marrow. RT-qPCR and Western blotting showed that YQSSF up-regulated the expression levels of CDK4, CDK6, CyclinB1, c-Myc and Bcl-2, as well as down-regulated the expression levels of Cyt-c, Fas, Caspase-8/3 and p53. ConclusionsYQSSF promotes the proliferation and inhibits the apoptosis of bone marrow cells to relieve chemotherapy-induced myelosuppression.

Radioprotective effects of gallic acid on bone marrow cells in mice

To investigate the radioprotective effect of gallic acid(GA) on mouse bone marrow cells. Healthy male ICR mice were randomly divided into saline control group, GA control group, X-ray irradiation group and GA protection group, with 10 mice in each group. X-ray irradiation group and normal saline control group were given 0.01 mL/g normal saline gavage, GA control group and GA protection group were given 200 mg/kg GA(20 mg/mL) gavage once a day for 14 consecutive days. On the 15 th day, 4 X-ray irradiation groups and 4 GA protection groups were given one-time X-ray irradiation to the whole body of the mice, and the absorbed doses were 1.0, 2.0, 3.0 and 4.0 Gy, respectively. The saline control group and the GA control group were not irradiated. After irradiation, detected the whole blood catalase(CAT), superoxide dismutase(SOD), malondialdehyde(MDA) and micronucleus frequency of polychromatic erythrocyte in bone marrow(MN-PCE), and use flow cytometry to detect bone marrow cell cycle, early apoptosis rate and late apoptosis rate. The CAT activities in the serum of mice in the 1.0, 2.0, 3.0 and 4.0 Gy GA protection groups were 2.13, 1.74, 1.49 and 1.15 U/mL, respectively, which were significantly increased compared with the corresponding X-ray irradiation group(P&lt;0.01). SOD activities were 184.69, 156.92, 139.17 and 107.15 U/mL, which were significantly increased compared with the corresponding X-ray irradiation group(P&lt;0.01). The contents of MDA were 3.92, 4.20, 6.32 and 9.31 nmol/mL, which were significantly lower than those of the corresponding X-ray irradiation group(P&lt;0.05, P&lt;0.01). The bone marrow MN-PCE rate of the mice in the 1.0, 2.0, 3.0 and 4.0 Gy GA protection groups were 4.35‰, 8.00‰, 12.90‰ and 3.80‰, respectively, which were significantly lower than those in the corresponding X-ray irradiation group(P&lt;0.01). The proportions of G_0/G_1 phase cells of bone marrow cells in the 1.0, 2.0, 3.0 and 4.0 Gy GA protection group were 81.00%, 86.28%, 92.04% and 93.15%, respectively, which were significantly reduced compared with the corresponding X-ray irradiation group(P&lt;0.01). The proportions of G_2/M phase cells were 4.51%, 3.05%, 2.35% and 1.81%, which were significantly increased compared with the corresponding X-ray irradiation group(P&lt;0.05, P&lt;0.01). The proportions of S phase cells were 15.32%, 11.36%, 5.96% and 4.92%, which were significantly increased compared with the corresponding X-ray irradiation group(P&lt;0.01). The early apoptosis rate of bone marrow cells of mice in the 1.0, 2.0, 3.0 and 4.0 Gy GA protection groups were 3.32%, 8.96%, 12.11% and 2.26%, respectively, which were significantly reduced compared with the corresponding X-ray irradiation group(P&lt;0.01). The late apoptosis rates of bone marrow cells were 7.21%, 11.73%, 17.11% and 19.36%, which were significantly reduced compared with the corresponding X-ray irradiation group(P&lt;0.05, P&lt;0.01). GA can reduce the oxidative damage, DNA damage and bone marrow cell cycle arrest of the bone marrow cells of radiation-damaged mice, inhibit the apoptosis of bone marrow cells, and have radioprotective effects on the bone marrow cells of mice.

Deficiency of the E3 Ligase Hoip Impairs Adult Hematopoiesis and Myeloid Leukemia

Ubiquitination is a post-translational modification that plays important roles in the regulation of various cellular processes. The linear ubiquitin chain assembly complex (LUBAC) is the only E3 ubiquitin ligase, which can specifically generate linear ubiquitin chains. LUBAC is composed of three subunits: catalytic Hoip (Rnf31), Hoil-1l (RBCK1), and Sharpin. LUBAC regulates canonical NF-κB signaling pathway and apoptosis. Several studies have shown that LUBAC is required for fetal hematopoiesis and tumorigenesis in several solid cancers, but the role of Hoip, which is the catalytic component of the LUBAC, in adult hematopoiesis and myeloid leukemia is unclear.To address whether Hoip is required for adult hematopoiesis, we used tamoxifen induced Hoip deleted mice (Hoip fl/fl; Rosa26-CreERT). Deletion of Hoip reduced the numbers of almost all cell fractions in bone marrow and peripheral blood, except for long-term hematopoietic stem cell (LT-HSC) fraction (CD34 - Flk2 - Lineage - c-Kit + Sca-1 +: LSK). Deletion of Hoip treated with tamoxifen markedly impaired colony formation of LT-HSCs in vitro. Among competitive transplantation assay using bone marrow cells from Hoip fl/fl; Rosa26-CreERT mice, deletion of Hoip treated with tamoxifen following stable reconstitution 8 weeks after transplantation led to a significant reduction of Hoip-deficient chimerism compared to control in vivo (Figure A). Deletion of Hoip induced apoptosis in bone marrow cells and increased the frequency of CD34 - LSK cells in S/G2/M phase of the cell cycle. Collectively, these data indicated that Hoip is required for adult hematopoiesis.To evaluate the consequences of Hoip deletion in myeloid leukemia propagation and maintenance, we utilized aggressive murine myeloid leukemia models driven by retroviral transduction of oncogenes: MLL-AF9 and NRAS G12V-driven acute myeloid leukemia (AML) and BCR-ABL and NUP98-HOXA9-driven blast crisis of chronic myelogenous leukemia (CML-BC) models. Deletion of Hoip in established leukemia cells treated with tamoxifen markedly impaired colony formation of leukemia cells in vitro and led to a significantly longer survival with reduced disease burden in bone marrow and spleen in vivo in both of leukemic models (Figure B,C). Deletion of Hoip also induced apoptosis in leukemia stem cells (LSCs: c-Kit + Lineage - cells) (Figure D) and increased the frequency of LSCs in S-phase of the cell cycle. Furthermore, we evaluated the contribution of HOIP to human myeloid leukemia. Knockdown of HOIP by small hairpin RNA using lentivirus in several myeloid leukemia cell lines (THP-1, SKM-1, and K562) and primary patient-derived AML cells exhibited reduced numbers of colony forming cells in vitro, and increased apoptosis. LUBAC inhibitor gliotoxin impaired the growth of murine and human leukemia cells. These results indicate that Hoip is essential for propagation and maintenance in murine and human myeloid leukemia.Because LUBAC regulates canonical NF-κB signaling pathway, we evaluated protein levels of p65 phosphorylation on Ser536 (p-p65) and IκBα in leukemia cells by flow cytometric analysis. Reduction in p-p65 and inhibition of IκBα degradation were observed in Hoip-deficient leukemia cells (Figure E), indicating that Hoip plays an important role in regulation of NF-κB signaling in myeloid leukemia.Since Hoip is the central component of LUBAC and the only catalytically active subunit of E3 ubiquitin ligase, we examined the importance of each domain of Hoip for myeloid leukemia propagation using Hoip mutant isoforms. Loss of colony-forming ability of Hoip-deficient AML cells could not be rescued by retroviral transduction of the Hoip mutants with deletion of UBA domain (which is required for interaction with the other LUBAC subunits) and with deletion of RBR domain and with mutation in C879A (which lack ligase activity) (Figure F), indicating that LUBAC ligase activity and interaction with the other LUBAC subunits are critical for leukemia propagation.Thus, our data demonstrated that Hoip is essential for adult hematopoiesis and myeloid leukemia. Given that patients with myeloid leukemia have shown increased activity of NF-κB signaling, inhibition of LUBAC ligase activity could serve as a promising strategy for treating myeloid leukemia. [Display omitted] DisclosuresJimbo: Japan Society for the Promotion of Science: Research Funding. Ito: Japan Society for the Promotion of Science: Research Funding; Institute for Frontier Life and Medical Sciences, Kyoto University: Research Funding. Iwama: Nissan Chemical Corporation: Research Funding. Nannya: Otsuka Pharmaceutical Co., Ltd.: Consultancy, Speakers Bureau; Astellas: Speakers Bureau. Konuma: Japan Society for the Promotion of Science: Research Funding; The Japanese Society of Hematology: Research Funding; SGH Foundation: Research Funding; Institute for Frontier Life and Medical Sciences, Kyoto University: Research Funding.

Fractionated Irradiation of Right Thorax Induces Abscopal Damage on Bone Marrow Cells via TNF-α and SAA.

Radiation-induced abscopal effect (RIAE) outside of radiation field is becoming more attractive. However, the underlying mechanisms are still obscure. This work investigated the deleterious effect of thoracic irradiation (Th-IR) on distant bone marrow and associated signaling factors by irradiating the right thorax of mice with fractionated doses (8 Gy × 3). It was found that this localized Th-IR increased apoptosis of bone marrow cells and micronucleus formation of bone marrow polychromatic erythrocytes after irradiation. Tandem mass tagging (TMT) analysis and ELISA assay showed that the concentrations of TNF-α and serum amyloid A (SAA) in the mice were significantly increased after Th-IR. An immunohistochemistry assay revealed a robust increase in SAA expression in the liver rather than in the lungs after Th-IR. In vitro experiments demonstrated that TNF-α induced SAA expression in mouse hepatoma Hepa1–6 cells, and these two signaling factors induced DNA damage in bone marrow mesenchymal stem cells (BMSCs) by increasing reactive oxygen species (ROS). On the other hand, injection with TNF-α inhibitor before Th-IR reduced the secretion of SAA and attenuated the abscopal damage in bone marrow. ROS scavenger NAC could also mitigated Th-IR/SAA-induced bone marrow damage in mice. Our findings indicated that Th-IR triggered TNF-α release from lung, which further promoted SAA secretion from liver in a manner of cascade reaction. Consequently, these signaling factors resulted in induction of abscopal damage on bone marrow of mice.

Hesperidin mitigates inflammation and modulates ectoenzymes activity and some cellular processes in complete Freund's adjuvant-induced arthritic rats.

This study was aimed at assessing the anti-arthritic effects of hesperidin on the inflammatory markers in serum/plasma, ectoenzymes activity in platelet, reactive oxygen species (ROS), apoptosis and cell cycle in bone marrow cells of a rat model of arthritis. Fifty-six adult female Wistar rats (245-274 g) were grouped into eight of seven rats each: control rats given normal saline or 40 mg/kg of hesperidin or 80 mg/kg of hesperidin, 0.2 mg/kg of dexamethasone, arthritic rats given normal saline, or 40 mg/kg of hesperidin or 80 mg/kg of hesperidin, and 0.2 mg/kg of dexamethasone. Myeloperoxidase and nitrate plus nitrite levels were evaluated in the plasma and serum, respectively. The ecto-nucleoside triphosphate diphosphohydrolases, ecto-5'-nucleotidase and ecto-adenosine deaminase activities were assessed in platelets. Subsequently, the cells of the bone marrow were obtained, and the assays for ROS, apoptosis and cell cycle were evaluated using flow cytometry. The results showed that hesperidin mitigated inflammation, modulated adenosine nucleotides and nucleoside hydrolysing enzymes and levels, minimized ROS intracellularly, attenuated apoptotic process and activated cell cycle arrest in arthritic rat. This study suggests that hesperidin could be a natural and promising anti-inflammatory compound for the management of arthritis.

Haploinsufficiency of Multiple Genes on Del(5q) Cooperate to Induce B Cell Abnormalities in Mice

Interstitial deletions on chromosome 5q [del(5q)] are the most common cytogenetic alteration in patients with myelodysplastic syndrome (MDS), affecting up to 25% of patients. The size of the deletion and the breakpoints vary among patients and include two commonly deleted regions (CDR). The distal CDR is located between 5q32-5q33 and the proximal CDR is located on 5q31. Several genes in the CDRs have been implicated in del(5q)-associated disease pathogenesis through haploinsufficiency, including RPS14, SPARC, miR-145 and miR-146 in the distal CDR, and EGR1, CTNNA1, and HSPA9 in the proximal CDR. Most patients have deletions that span both CDRs, therefore, we asked whether simultaneous deletion of genes on both CDRs cooperate to contribute to altered hematopoiesis.In this study, we crossed Hspa9+/- mice (a gene on the proximal CDR) with Cd74-Nid67fl/+ mice (loxP sites flanking 8 distal CDR genes , Nid67, Dctn4, Rbm22, Myoz3, Synpo, Ndst1, Rps14 and Cd74) . Cd74-Nid67fl/+ mice also express the Lmo2-Cre transgene that is expressed during embryonic hematopoiesis. We comprehensively characterized the hematopoiesis in (1) wild type control mice, (2) Hspa9+/- mice, (3) Lmo2-Cre+ mice, (4) Cd74-Nid67fl/+ ; Lmo2-Cre+ mice, and (5) double mutant Hspa9+/- ; Cd74-Nid67fl/+ ; Lmo2-Cre+ mice. We observed the previously reported reduction in bone marrow colony forming unit-preB (CFU-preB) colony formation in Hspa9+/- single-mutant mice. We also observed the reported anemia with decreased RBC maturation (n=4-8, P<0.05) and increased apoptosis in bulk bone marrow cells (n=4-8, P<0.05) in Cd74-Nid67fl/+ ; Lmo2-Cre+ (Cd74-Nid67+/-) mice. At 18 months of age, Cd74-Nid67+/- mice also developed reduction in B cell frequency in the bone marrow (BM) (≥2.1-fold, n=3-5, P<0.01), spleen (≥1.4 -fold, n=3-5, P<0.05) and peripheral blood (≥2.0-fold, n=3-5, P<0.05) (Figure 1a) that was associated with reduction in CFU-preB methylcellulose colonies (≥8.4-fold, n=3-5, P<0.001) compared to wild type and Lmo2-Cre+ control mice (Figure 1b). Hspa9+/- ; Cd74-Nid67fl/+ ; Lmo2-Cre+ double mutant mice showed a reduction of CFU-PreB methylcellulose colonies compared to wild type and Lmo2-Cre+ control mice (≥42.4-fold, n=3-5, P<0.001) (Figure 1b). Hspa9+/- ; Cd74-Nid67fl/+ ; Lmo2-Cre+ mice also developed a reduction in common lymphoid progenitors (≥1.6-fold, n=3-5, P<0.05) and Hardy B cell fractions A-E (≥3.4-fold, n=3-5, P<0.05) in the BM, with at least a 2-fold reduction in mature B cell frequencies in the BM, spleen and peripheral blood (n=3-5, P<0.05) compared to wild type, Lmo2-Cre+ and Hspa9+/- control mice (Figure 1a). These data suggest that haploinsufficiency of Hspa9 cooperates with haploinsufficiency of one or more genes deleted in Cd74-Nid67+/- mice to reduce B cells. We next asked which of the 8 genes on the Cd74-Nid67 deleted interval contributed to the B cell defect.CD74 is a transmembrane protein expressed on antigen presenting cells and mediates major histocompatibility (MHC) class II assembly and trafficking. It has been suggested to regulate mature B cell survival through macrophage migration inhibitory factor (MIF) signaling. To better understand the role of CD74 in hematopoiesis, we characterized B cells in Cd74 knockout mice. We observed that Cd74 homozygous and heterozygous knockoutmice (2-3 months old) have decreased CFU-PreB colonies in BM compared to wild type control mice (4.4-fold, n=4, P<0.01). The Cd74-/- mice, but not Cd74+/- mice, also have decreased peripheral blood B cells (1.5-fold, n=4, P<0.01) at 3 months. This result indicates that loss of Cd74 likely contributes to the B cell phenotypes observed in the Cd74-Nid67+/- mice. We predict that heterozygous loss of Cd74 and Hspa9 will cooperate to induce similar B cell phenotypes observed in Hspa9+/-; Cd74-Nid67+/- double mutant mice. These studies are ongoing by intercrossing Cd74+/- and Hspa9+/- mice, as well as mechanistic studies to understand how Hspa9 and Cd74 haploinsufficiency regulate B cell development. Collectively, these studies may provide insight into B cell alterations that occur in MDS patients with del(5q). [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Bone marrow cells are differentiated into MDSCs by BCC-Ex through down-regulating the expression of CXCR4 and activating STAT3 signalling pathway.

Studies showed that the increase of myeloid‐derived suppressor cells (MDSCs) in tumour microenvironment is closely related to the resistant treatment and poor prognosis of metastatic breast cancer. However, the effect of tumour‐derived exosomes on MDSCs and its mechanism are not clear. Here, we reported that breast cancer cells (4T1)‐secreted exosomes (BCC‐Ex) were able to differentiate bone marrow cells into MDSCs and significantly inhibited the proliferation of T lymphocytes to provide an immunosuppressive microenvironment for cancer cells in vivo and in vitro. The number of MDSCs in bone marrow and spleen of 4T1 tumour‐bearing mice and BCC‐Ex infused mice was significantly higher than that of normal mice, whereas the number of T lymphocytes in spleen was significantly decreased. In addition, BCC‐Ex markedly promoted the differentiation of MDSCs from bone marrow cells or bone marrow cells derived macrophages, seen as the increased expressions of MDSCs‐related functional proteins Arginase‐1 (Arg‐1) and inducible nitric oxide synthase (iNOS). Furthermore, BCC‐Ex significantly down‐regulated the expressions of chemokine receptor CXCR4 and markedly up‐regulated the levels of inflammatory cytokines IL‐6 and IL‐10 in bone marrow cells and macrophages and remarkably inhibited the division and proliferation of T cells. Importantly, CXCR4 agonist, CXCL12, could reverse the function of BCC‐Ex, indicating that BCC‐Ex‐induced MDSCs might be dependent on the down‐regulation of CXCR4. Western blot showed that BCC‐Ex significantly promoted the phosphorylation of STAT3 in bone marrow cells, resulting in the inhibitions of the proliferation and apoptosis of bone marrow cells, and the aggravation of the differentiation of bone marrow cells into MDSCs.