bims-iorami 2023-10-08 papers

bims-iorami

Biomed News

on Ionising Radiation and Mitochondria

Issue of 2023–10–08
eight papers selected by
Chenxiao Yu, Soochow University

Immunomodulatory effects of histone variant H2A.J in ionizing radiation dermatitis.
Nuclear genome influences mitochondrial DNA.
DNA damage-induced senescence is associated with metabolomic reprogramming in breast cancer cells.
Tumor Cell-Intrinsic PD-L1 Effects on Radiation-Induced Locoregional Antitumor Immunity.
Innate immune response restarts adaptive immune response in tumors.
TFAM Modulates Cardiomyocytes Pyroptosis Induced by Ionizing Radiation through mtDNA/TLR9/NF-kB Pathway.
Mitochondrial DNA damage triggers spread of Parkinson's disease-like pathology.
Doxorubicin Enhances the Abscopal Effect Depending on Tumor Cell Mitochondrial DNA and cGAS/STING.

Int J Radiat Oncol Biol Phys. 2023 Sep 25. pii: S0360-3016(23)07934-8. [Epub ahead of print]

Immunomodulatory effects of histone variant H2A.J in ionizing radiation dermatitis.

Gargi Tewary, Benjamin Freyter, Mutaz Abd Al-Razaq, Hendrik Auerbach, Matthias W Laschke, Tanja Kübelbeck, Antonia Kolb, Adèle Mangelinck, Carl Mann, Daniela Kramer, Claudia E Rübe.

   PURPOSE: Histone variant H2A.J is associated with premature senescence following ionizing radiation (IR) and modulates senescence-associated secretory phenotype (SASP). Using constitutive H2A.J knock-out mice, the role of H2A.J was investigated in radiation dermatitis.
EXPERIMENTAL DESIGN: H2A.J wild-type (WT) and knock-out (KO) mice were exposed to moderate or high IR doses (≤20Gy, skinfold IR). Radiation-induced skin reactions were investigated up to 2 weeks post-IR at macroscopic and microscopic level. H2A.J and other senescence markers, as well as DNA damage and proliferation markers were studied by immunohistochemistry, immunofluorescence, and electron microscopy. Following high-dose IR, protein-coding transcriptomes were analyzed by RNA-sequencing, immune cell infiltration by flow cytometry and gene expression by RT-PCR in (non-) irradiated WT versus KO skin.
RESULTS: In WT skin epidermal keratinocytes showed time- and dose-dependent H2A.J accumulation following IR exposure. Unexpectedly, stronger inflammatory reactions with increased epidermal thickness and progressive hair follicle loss were observed in irradiated KO versus WT skin. Clearly more radiation-induced senescence was observed in keratinocyte populations of KO skin after moderate and high doses, with hair follicle stem cells being particularly badly damaged, leading to follicle atrophy. Following high-dose IR, transcriptomic analysis revealed enhanced senescence-associated signatures in irradiated KO skin, with intensified release of SASP factors. Flow cytometric analysis indicated increased immune cell infiltration in both WT and KO skin, however, specific chemokine-mediated signaling in irradiated KO skin led to more neutrophil recruitment, thereby aggravating radiation toxicities. Increased skin damage in irradiated KO skin led to hyperproliferation, abnormal differentiation, and cornification of keratinocytes, accompanied by increased upregulation of transcription-factor JunB.
CONCLUSION: Lack of radiation-induced H2A.J expression in keratinocytes is associated with increased senescence induction, modulation of SASP expression, and exacerbated inflammatory skin reactions. Hence, epigenetic H2A.J-mediated gene expression in response to IR regulates keratinocyte immune functions and plays an essential role in balancing the inflammatory response during radiation dermatitis.

Keywords:  cellular senescence; ionizing radiation, radiation dermatitis, histone variant H2A.J; senescence-associated secretory phenotype (SASP)

DOI:  https://doi.org/10.1016/j.ijrobp.2023.09.022
Nat Rev Genet. 2023 Oct 06.

Nuclear genome influences mitochondrial DNA.

Henry Ertl.

DOI: https://doi.org/10.1038/s41576-023-00667-w
Biochimie. 2023 Sep 25. pii: S0300-9084(23)00248-1. [Epub ahead of print]

DNA damage-induced senescence is associated with metabolomic reprogramming in breast cancer cells.

Neena George, Manjunath B Joshi, Kapaettu Satyamoorthy.

  Senescence due to exogenous and endogenous stresses triggers metabolic reprogramming and is associated with many pathologies, including cancer. In solid tumors, senescence promotes tumorigenesis, facilitates relapse, and changes the outcomes of anti-cancer therapies. Hence, cellular and molecular mechanisms regulating senescent pathways make attractive therapeutic targets. Cancer cells undergo metabolic reprogramming to sustain the growth-arrested state of senescence. In the present study, we aimed to understand the metabolic reprogramming in MCF-7 breast tumor cells in response to two independent inducers of DNA damage-mediated senescence, including ionizing radiation and doxorubicin. Increased DNA double-strand breaks, as demonstrated by γH2AX staining, showed a senescence phenotype, with expression of senescence-associated β-galactosidase accompanied by the upregulation of p21 and p16 in both groups. Further, untargeted analysis of the senescence-related extracellular metabolome profile of MCF-7 cells showed significantly reduced concentrations of carnitine and pantothenic acid and increased levels of S-adenosylhomocysteine in doxorubicin-treated cells, indicating the accumulation of ROS mediated DNA damage and impaired mitochondrial membrane potential. Similarly, a significant decline in the creatine level was observed in radiation-exposed cells, suggesting an increase in oxidative stress-mediated DNA damage. Our study, therefore, provides key effectors of the metabolic changes in doxorubicin and radiation-induced early senescence in MCF-7 breast cancer cells.

Keywords:  Cellular senescence; Doxorubicin; Ionizing radiation; MCF-7 cells; Metabolomic profiling; Mitochondrial dysregulation

DOI:  https://doi.org/10.1016/j.biochi.2023.09.021
Int J Radiat Oncol Biol Phys. 2023 Oct 01. pii: S0360-3016(23)05564-5. [Epub ahead of print]117(2S): e224

Tumor Cell-Intrinsic PD-L1 Effects on Radiation-Induced Locoregional Antitumor Immunity.

C A Clark, Z Zhang, Y Zhang, C Xing, B Larimer, E S Yang.

PURPOSE/OBJECTIVE(S): Targeting PD-L1 is a beneficial strategy to reinvigorate antitumor immunity, however variable response and resistance are challenging and suggest the need for multimodality approaches. Tumor cell-intrinsic PD-L1 signals also regulate non-canonical pathogenic pathways that may impact treatment resistance. Ionizing radiation (IR) can induce antitumor immunity and has demonstrated therapeutic synergy with immunotherapy in some cases, however tumor-driven immunologic mechanisms affecting clinical outcomes remain incompletely understood. In this study, we investigated the impact of tumor cell-intrinsic PD-L1 signals on IR-induced locoregional immune response and tumor control.
MATERIALS/METHODS: We used orthotopic B16-F10 melanoma (WT-B16) and 4T1 triple negative breast cancer (WT-4T1) murine tumor models, as well as PD-L1 disabled variants (KO) generated by CRISPR/Cas9, implanted bilaterally. IR (10 Gy) was targeted at one tumor alone to evaluate both direct and indirect IR effects based on tumor PD-L1 status. We evaluated response by tumor volume (TV) measurements, flow cytometry of tumor-infiltrating lymphocytes (TILs) and tumor draining lymph nodes (TDLNs) in both irradiated and unirradiated compartments, and granzyme B (GZB) PET imaging to assess functional in vivo changes. Chemokine-based multiplex assays were used to assess cell lines receiving IR (4Gy) and ex vivo tumor lysates and serum.
RESULTS: IR-induced local tumor control was not significantly affected based on tumor PD-L1 status, however deactivation of tumor cell PD-L1 enhanced IR-induced regional tumor control. Unirradiated WT tumors in mice harboring irradiated KO but not irradiated WT tumors demonstrated a significant mean reduction in TV with instances of complete distant tumor regression. PET imaging demonstrated a nearly 2-fold higher concentration of GZB in KO versus WT tumors, in line with known locally immunosuppressive effects of tumor PD-L1. Remarkably, GZB levels were >1.5-fold higher in unirradiated WT tumors in mice harboring an irradiated KO versus WT tumor, which correlated with a 50% increase in PD-1+CD8+ T cells. Higher levels of CD62+CD44- naïve CD4+ (4-fold) and CD8+ (2-fold) memory T cells were seen in TDLNs of irradiated KO versus WT tumors. Cytokine levels positively correlated with immune recruitment and activation status, as CXCL10, CCL2 and CCL5 were significantly upregulated in PD-L1 KO versus WT tumors cells.
CONCLUSION: Results from this study demonstrate cell-intrinsic PD-L1 inhibits IR-induced locoregional immune activation and frequency of regional tumor control, with clinical implications including therapeutic targeting of tumor cell-intrinsic PD-L1 signals to enhance IR-induced immunogenicity, utility of IR based on tumor PD-L1 status particularly in the metastatic setting, and immunotherapy combinations. Future studies investigating mechanisms of resistance to IR-induced immune activation to enhance responsiveness are warranted.

DOI: https://doi.org/10.1016/j.ijrobp.2023.06.1130
Front Immunol. 2023 ;14 1260705

Innate immune response restarts adaptive immune response in tumors.

Wen-Shan Li, Qing-Qing Zhang, Qiao Li, Shang-Yu Liu, Guo-Qiang Yuan, Ya-Wen Pan.

  The imbalance of immune response plays a crucial role in the development of diseases, including glioblastoma. It is essential to comprehend how the innate immune system detects tumors and pathogens. Endosomal and cytoplasmic sensors can identify diverse cancer cell antigens, triggering the production of type I interferon and pro-inflammatory cytokines. This, in turn, stimulates interferon stimulating genes, enhancing the presentation of cancer antigens, and promoting T cell recognition and destruction of cancer cells. While RNA and DNA sensing of tumors and pathogens typically involve different receptors and adapters, their interaction can activate adaptive immune response mechanisms. This review highlights the similarity in RNA and DNA sensing mechanisms in the innate immunity of both tumors and pathogens. The aim is to enhance the anti-tumor innate immune response, identify regions of the tumor that are not responsive to treatment, and explore new targets to improve the response to conventional tumor therapy and immunotherapy.

Keywords:  DNA sensing; RNA sensing; crosstalk; glioblastoma; type I interferon

DOI:  https://doi.org/10.3389/fimmu.2023.1260705
Int J Radiat Oncol Biol Phys. 2023 Oct 01. pii: S0360-3016(23)04889-7. [Epub ahead of print]117(2S): S119-S120

TFAM Modulates Cardiomyocytes Pyroptosis Induced by Ionizing Radiation through mtDNA/TLR9/NF-kB Pathway.

G Cai, J Yu, X Meng.

PURPOSE/OBJECTIVE(S): Mitochondrial transcription factor A (TFAM) is a pivotal factor for regulating mitochondrial DNA (mtDNA) replication, transcription and biogenesis. Previous studies have reported that cytosolic mtDNA stress can lead to cardiomyocytes pyroptosis, which is characterized by inflammasome formation. In this study, we attempted to investigate the mechanism of TFAM regulate cardiomyocytes pyroptosis induced by ionizing radiation.
MATERIALS/METHODS: The peripheral blood serum of patients with esophageal cancer before and after definitive chemoradiotherapy was collected for Luminex multiplex cytokine assays. C57BL/6 mice were irradiated with the whole heart using small animal radiation research platform (SARRP) to construct a radiation-induced myocardial damage (RIMD) mouse model, and the ventricular function was evaluated using 9.4T Bruker magnetic resonance (MR) scanner. The function changes of cardiomyocytes exposed to radiation were observed in vitro and in vivo after knocking out GSDMD. Furthermore, the changes of mitochondrial function, the levels of cytosolic mtDNA, and the protein levels of NF-kB and pyroptosis pathway in irradiated cardiomyocytes were analyzed by knockdown and overexpression of TFAM in vitro and in vivo.
RESULTS: By multifactor cytokine assays we found that pyroptosis related IL-1β and IL-18 were significantly increased in patients with high mean heart dose (MHD) after radiotherapy, while those with low MHD were not significantly increased after radiotherapy. Next, we successfully constructed the RIMD mouse model using a single heart irradiation of 20 Gy. We found that the gene expression of pyroptosis pathway was significantly up-regulated after cardiac irradiation by myocardial tissue transcriptomic sequencing. Compared with wild-type (WT) mice, cardiac systolic function of Gsdmd-/- mice was significantly improved at 1, 2, 6, 12, and 24 weeks after heart irradiation. In vitro, we also demonstrated increased viability of irradiated cardiomyocytes by knocking out GSDMD. In vitro and in vivo experiments confirmed the expression of TFAM decreased after radiation. By overexpression of TFAM, we found that irradiated cardiomyocytes showed improved mitochondrial function, decreased release of mtDNA into cytoplasm through mitochondrial permeability transition pores (mPTPs), decreased binding of cytosolic mtDNA to TLR9, and decreased expression of NF-kB and pyroptosis pathway proteins. Dual luciferase gene reporter assays and Chromatin immunoprecipitation (CHIP) assay confirmed that p65 could bind the NLRP3 promoter region. In addition, we found that ventricular function deteriorated and improved in mice with knockdown and overexpression of TFAM through adeno-associated virus serotype 9 (AAV9), respectively.
CONCLUSION: Our study indicated that TFAM regulate irradiated cardiomyocytes pyroptosis through mtDNA/TLR9/NF-kB pathway. We provide a novel mechanism of RIMD, revealing an underappreciated intervention target for RIMD.

DOI: https://doi.org/10.1016/j.ijrobp.2023.06.455
Mol Psychiatry. 2023 Oct 02.

Mitochondrial DNA damage triggers spread of Parkinson's disease-like pathology.

Emilie Tresse, Joana Marturia-Navarro, Wei Qi Guinevere Sew, Marina Cisquella-Serra, Elham Jaberi, Lluis Riera-Ponsati, Natasha Fauerby, Erling Hu, Oliver Kretz, Susana Aznar, Shohreh Issazadeh-Navikas.

In the field of neurodegenerative diseases, especially sporadic Parkinson's disease (sPD) with dementia (sPDD), the question of how the disease starts and spreads in the brain remains central. While prion-like proteins have been designated as a culprit, recent studies suggest the involvement of additional factors. We found that oxidative stress, damaged DNA binding, cytosolic DNA sensing, and Toll-Like Receptor (TLR)4/9 activation pathways are strongly associated with the sPDD transcriptome, which has dysregulated type I Interferon (IFN) signaling. In sPD patients, we confirmed deletions of mitochondrial (mt)DNA in the medial frontal gyrus, suggesting a potential role of damaged mtDNA in the disease pathophysiology. To explore its contribution to pathology, we used spontaneous models of sPDD caused by deletion of type I IFN signaling (Ifnb-/-/Ifnar-/- mice). We found that the lack of neuronal IFNβ/IFNAR leads to oxidization, mutation, and deletion in mtDNA, which is subsequently released outside the neurons. Injecting damaged mtDNA into mouse brain induced PDD-like behavioral symptoms, including neuropsychiatric, motor, and cognitive impairments. Furthermore, it caused neurodegeneration in brain regions distant from the injection site, suggesting that damaged mtDNA triggers spread of PDD characteristics in an "infectious-like" manner. We also discovered that the mechanism through which damaged mtDNA causes pathology in healthy neurons is independent of Cyclic GMP-AMP synthase and IFNβ/IFNAR, but rather involves the dual activation of TLR9/4 pathways, resulting in increased oxidative stress and neuronal cell death, respectively. Our proteomic analysis of extracellular vesicles containing damaged mtDNA identified the TLR4 activator, Ribosomal Protein S3 as a key protein involved in recognizing and extruding damaged mtDNA. These findings might shed light on new molecular pathways through which damaged mtDNA initiates and spreads PD-like disease, potentially opening new avenues for therapeutic interventions or disease monitoring.

DOI: https://doi.org/10.1038/s41380-023-02251-4
Int J Radiat Oncol Biol Phys. 2023 Oct 01. pii: S0360-3016(23)05018-6. [Epub ahead of print]117(2S): S158

Doxorubicin Enhances the Abscopal Effect Depending on Tumor Cell Mitochondrial DNA and cGAS/STING.

L Wang, R Luo, K Onyshchenko, G Niedermann.

PURPOSE/OBJECTIVE(S): Localized radiotherapy (RT) can cause a T cell-mediated abscopal effect on non-irradiated tumor lesions, especially in combination with immune checkpoint blockade (ICB). However, this effect is still clinically rare and improvements are highly desirable. We investigated whether triple combination with a low dose of clinically approved liposomal doxorubicin (Doxil) could augment abscopal responses compared with RT+ICB, Doxil+ICB, or RT+Doxil.
MATERIALS/METHODS: We used Doxil in combination with RT and αPD1 in two tumor models (B16-CD133 melanoma and MC38 colon carcinoma) with mice bearing two tumors, only one of which was irradiated.
RESULTS: Triple therapy with RT, αPD1, and single low-dose Doxil strongly enhanced the RT-induced abscopal effect compared to all double and single treatments in both tumor models (p < 0.05, n = 5-10 mice/group). Complete cures of non-irradiated tumors were mainly observed in triple-treated mice. Triple therapy induced more cross-presenting dendritic cells (DCs) and tumor-specific CD8 T cells than RT/αPD1 and Doxil/αPD1 (p < 0.05, n = 5 mice/group), particularly in non-irradiated tumors. CD8 T cell depletion or implanting STING-deficient tumor cells abolished the abscopal effect. By using inhibitors and knockout cells, we show that doxorubicin/Doxil-induced IFNβ1 markedly depended on the cGAS/STING pathway (p < 0.05) which drives antitumor CD8 T cell responses through cross-presenting DCs. In mitochondrial DNA (mtDNA)-depleted tumor cells, doxorubicin/Doxil induced less IFNβ1 (p < 0.05), the related T cell-recruiting chemokine CXCL10 (p < 0.0001), and ATP (p < 0.0001); coincubation with mtDNA-depleted tumor cells strongly reduced IFNβ1 (p < 0.01) secretion by DCs. Implantation of mtDNA-depleted tumor cells, particularly at the non-irradiated site, substantially diminished the Doxil-enhanced abscopal effect and tumor infiltration by tumor-specific CD8 T cells (p < 0.05).
CONCLUSION: Single low-dose Doxil can substantially enhance the RT-induced abscopal effect, with a strong increase in cross-presenting DCs and CD8 tumor-specific T cells particularly in abscopal tumors compared with RT/αPD1 and Doxil/αPD1. The mtDNA/cGAS/STING/IFN-I axis is important for the immunogenic doxorubicin effects. Our findings may be helpful for the planning of clinical radiochemoimmunotherapy trials in (oligo)metastatic patients.

DOI: https://doi.org/10.1016/j.ijrobp.2023.06.584