AIMS:Radiation-induced intestinal injury (RIII) significantly impairs the quality of life in patients with abdominal/pelvic cancer undergoing radiotherapy, often necessitating treatment cessation. The ACE2/Ang-(1-7)/MasR axis, a protective pathway within the renin-angiotensin system, represents a potential anti-inflammatory target. This study explored the role of ACE2 activation in mitigating RIII and the underlying mechanisms. RESULTS:Treatment with diminazene aceturate (DIZE), a selective ACE2 agonist, prior to lethal radiation blocked intestinal stem cell (ISC) death, enhanced crypt regeneration, preserved epithelial barrier integrity, and reduced intestinal inflammation, thereby promoting mice survival. Notably, the radioprotective effect of DIZE was reversed by ACE2 or MasR antagonists, and other ACE2 agonists exhibited similar radioprotective efficacy. DIZE treatment improved the survival of ISCs both in vitro and in vivo postradiation. Mechanistically, DIZE directly targeted intestinal epithelial cells (IECs), preventing the activation of radiation-induced MAPK (p38/JNK) and NF-κB pathways. This effect was abolished by ACE2 knockdown in a human intestinal epithelial cell line (HIECs) in vitro. Intriguingly, DIZE failed to inhibit endothelial cell apoptosis or attenuate MAPK/NF-κB pathway activation in irradiated endothelial cells. Preliminary evidence indicates DIZE did not affect the radiosensitivity of colorectal tumor cells or azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colorectal tumors in mice.Conclusion and Innovation:This study is the first to demonstrate selective ACE2-mediated intestinal protection without compromising tumor radiosensitivity. These findings demonstrate ACE2 activation selectively shields IECs from radiation damage by inhibiting MAPK/NF-κB pathways, offering a novel therapeutic strategy to alleviate RIII without compromising tumor radiosensitivity. Antioxid. Redox Signal. 44, 843-858.

Background and Purpose Radiation-induced ovarian injury (RIOI) compromises the clinical utility of pelvic radiotherapy and reduces fertility in young female patients. Dimethyl sulfoxide (DMSO) exhibits antioxidant property. Hearin, we aimed to explore the protective effect and underlying mechanism of DMSO on RIOI. Materials and Methods C57BL/6J female mice were treated with DMSO prior to undergoing lower abdominal radiation. Intragenerational and transgenerational fertility were assessed by mating experiment. Ovaries were harvested to evaluate follicle count and morphology. Granulosa cells were analyzed by immunohistochemical staining of TUNEL and Ki67. An ovary explant organ culture system was established to evaluate the effect of DMSO. Fluorescent probes were employed to evaluate mitochondrial mass and function. DNA double-strand breaks were detected by immunoblotting of γ-H2AX. Results DMSO preserved the fertility of irradiated mice and even safeguarded the reproductive capacity of their unirradiated female offspring. Histological analyses revealed that DMSO preserves the ovarian follicle reserve, including both primordial and developing follicles. Additionally, DMSO demonstrated radioprotective effects in ex vivo ovarian tissue. Moreover, DMSO reduced apoptosis and enhanced proliferation in granulosa cells. Mechanistically, DMSO alleviated radiation-induced oxidative stress and preserved mitochondrial function, as evidenced by increased mitochondrial mass, reduced oxidant levels, and enhanced mitochondrial membrane potential. Moreover, DMSO reduced the levels of DNA damage accumulation in vivo and in vitro . Conclusion Our data suggest that DMSO may offer a potential pharmacological treatment option for fertility impairment in women undergoing radiotherapy, which warrants further investigation in clinical settings.

PURPOSE:Radiation-induced skin injury is a common complication that seriously affects the follow-up treatment and life quality of tumor patients. Nocardia rubra cell-wall skeleton (N-CWS) has been reported to have pro-angiogenesis effects, and its role on RISI remains unclear. The aim of this study was to investigate its effect on repair of radiation induced skin injury. MATERIALS AND METHODS:After exposure to 45 Gy X-rays, the irradiated areas of SD rats were treated by N-CWS every 3 days. The radioprotective effects of N-CWS were evaluated by body weight changes, skin scores, H&E staining and TUNEL staining. Microvascular monitoring system and immunofluorescence staining of CD31 were performed to assess angiogenic capacity in vivo. In vitro, the activity and apoptosis of HUVECs were measured by CCK8 and flow cytometry. The angiogenic capacity of HUVECs was evaluated by tubule formation assay and Transwell assay. Western blot was performed to verify the possible mechanisms of the protective effect of N-CWS against radiation-induced skin damage. RESULTS:N-CWS was demonstrated to have low toxicity and radioprotective effects, maintained cell activity and attenuated radiation-induced apoptosis. In addition, N-CWS attenuated radiation-induced vascular injury in vivo and in vitro. Furthermore, P38 MAPK was shown to be associated with the radiation protection capability of N-CWS in HUVECs. CONCLUSIONS:N-CWS promoted the repair of radiation-induced skin injury by enhancing angiogenesis, and the mechanism was related to the activation of P38 MAPK.

Diabetic ischemic stroke leads to more severe brain damage. While the urokinase-type plasminogen activator receptor (PLAUR) is implicated in inflammation and cell migration, its precise role in diabetic stroke remains unclear. A streptozotocin-induced diabetic tMCAO mouse model was employed to simulate diabetic ischemic stroke. PLAUR expressions in mouse brain tissues were analyzed using microarray, Western blot, and immunofluorescence. PLAUR mRNA expression in endothelial cells (bEnd.3) was analyzed by RT-qPCR. We assessed cerebral infarct volume, brain water content, neurological deficits, and BBB integrity. Neutrophil infiltration (flow cytometry), inflammatory mediators, microglial polarization, and metabolic reprogramming (glycolytic proteins, ECAR/OCR) were investigated in vivo and in vitro. To test whether neutrophils are essential for PLAUR-mediated injury, we performed neutrophil depletion experiments using anti-Ly6G antibody, alone or combined with PLAUR knockdown. Neutrophil extracellular trap (NET) formation (CitH3 expression) and its impact on endothelial permeability and microglial polarization were also examined. PLAUR was significantly upregulated in the brains of diabetic stroke mice, particularly in microglia. PLAUR knockdown resulted in smaller infarct volumes, improved functional recovery, and maintained BBB integrity by restoring tight junction proteins. PLAUR knockdown was associated with reduced neutrophil infiltration, decreased pro-inflammatory mediator (MPO, MMP3) and attenuated pro-inflammatory M1 microglial polarization. PLAUR silencing also reduced NETosis in vivo and in isolated neutrophils. Neutrophil depletion alone significantly reduced infarct volume, improved neurological outcomes, and restored tight junction proteins; notably, PLAUR knockdown provided no additional benefit when neutrophils were already depleted, indicating that neutrophils are essential downstream effectors of PLAUR-mediated injury. Furthermore, PLAUR knockdown reversed the glycolytic shift in microglia. PLAUR is upregulated in diabetic ischemic stroke and its knockdown is associated with reduced neuroinflammation, preserved BBB integrity, decreased neutrophil infiltration, attenuated NETosis, and shifts in microglial polarization and metabolism. Therefore, targeting PLAUR represents a promising therapeutic strategy for attenuating brain injury in diabetic stroke.

The phosphatase PTEN is an important molecule for maintaining chromosome stability. PTEN deficiency induces DNA replication stress, confers stress tolerance, and disrupts mitotic spindle architecture, leading to the accumulation of structural and numerical chromosome instability. PTEN has many posttranslational modifications, including phosphorylation, acetylation and methylation; its modification level directly regulates protein levels and functions, thereby affecting the stability of the genome. It has been reported that Plk1, a Ser/Thr kinase, can directly phosphorylate PTEN at S380, impair its interaction with cdh1 and stabilize its association with chromatin. As the phosphorylation of PTEN at the STT motif is associated with the DNA damage response and Plk1 activity is inhibited when DNA damage occurs, it is not clear whether there are other upstream molecules that can regulate S380 phosphorylation, and if so, by what mechanism. We found that the ATM/Chk2 signaling pathway can affect PTEN p-S380 when DNA damage occurs and that PTEN p-S380, which may be regulated by ATM/Chk2, is involved in chromatin decondensation. These results suggest a role for PTEN modification by other kinases and provide a target for improving radiotherapy efficacy.

AIMS:Radiation-induced intestinal injury (RIII) severely compromises the quality of life in patients undergoing abdominal/pelvic radiotherapy and may necessitate treatment discontinuation. To date, there is no approved agent for the prevention or treatment of RIII. This study aims to clarify the protective effects of mannose on RIII and elucidate its mechanisms of action, in order to identify new safe and effective therapeutic agents and potential therapeutic targets for the prevention and treatment of RIII. RESULTS:Here, we report that intraperitoneal administration of mannose, a natural bioactive monosaccharide, at 24, 12, and 2 h prior to lethal irradiation increased the survival rate of mice from 0% to 50%. Specifically, mannose pretreatment significantly blocked crypt cell apoptosis, preserved epithelial barrier integrity, attenuated intestinal inflammation, and enhanced crypt regeneration. Additionally, mannose treatment enhanced the survival of intestinal stem cells both in vitro and in vivo following radiation exposure. We further confirmed that mannose maintains mitochondrial homeostasis and alleviates cellular oxidative stress. Moreover, mannose facilitated the repair of DNA double-strand breaks, thereby inhibiting aberrant mitosis after radiation exposure. Additionally, preliminary evidence indicates that mannose does not affect the radiosensitivity of colorectal tumor cells or azoxymethane/dextran sodium sulfate-induced colorectal tumors in mice.Conclusion and Innovation:Given its low toxicity and wide availability, our findings suggest that mannose represents a promising protective strategy for RIII. Antioxid. Redox Signal. 00, 000-000.

To investigate the functional and molecular mechanisms by which Piezo1regulates HT-22 hippocampal neuronal autophagy, and to explore whether Piezo1 regulates hippocampal neuronal autophagy via the Ca2+/Calpain, CaMKKβ, or Calcineurin pathways. The impacts of Piezo1 inhibition, activation and gene knockdown on the autophagy of HT22 neurons was investigated by Western blotting, PCR and immunofluorescence. The changes of intracellular calcium (Ca2+) concentration were also observed. To pinpoint the specific downstream Ca2+ signaling pathway by which Piezo1 modulates autophagy, the calcium chelator BAPTA-AM, the Calpain inhibitor PD151746, and the CaMKKβ inhibitor STO609 were employed either alone or in combination. Enhanced autophagy was observed when Piezo1 was activated using the agonist Yoda1, manifesting as increased release of autophagic vacuoles, enhanced LC3 II/LC3 I ratio, decreased p62 protein level, and elevated nuclear translocation and expression of the TFEB protein. ATG7 knockdown by ATG7 shRNA mitigated the effects of Yoda1 on LC3 II/LC3 I ratio and p62 protein levels. The Piezo1 inhibitor GsMTx4 partially reversed the autophagy caused by starvation in HT22 neurons while Yoda1 still activated autophagy in the presence of BDNF. Following Piezo1 knockdown, neuronal autophagy was decreased. Piezo1-induced autophagy was accompanied with an increased cytoplasmic concentration of Ca2+. The calcium chelator BAPTA-AM partly reversed Piezo1 activation-induced autophagy, which was also mitigated by blocking calcineurin/TFEB signaling or Calpain signaling. Piezo1 modulates the autophagy of HT-22 neurons by activating Ca2+/Calpain and Calcineurin/TFEB pathways.

AIMS:This study investigated the roles of lateral basal forebrain glial cell line-derived neurotrophic factor (GDNF) signaling and cholinergic neuron activity, apoptosis, and autophagy dysfunction in sleep deprivation-induced increased risk of chronic postsurgical pain (CPSP) in mice. METHODS:Sleep deprivation (6 h per day from -1 to 3 days postoperatively) was administered to mice receiving skin/muscle incision and retraction (SMIR) to determine whether perioperative sleep deprivation induces mechanical and thermal pain hypersensitivity, increases the risk of chronic pain, and causes changes of basal forebrain neurons activity (c-Fos immunostaining), apoptosis (cleaved Caspase-3 expression), autophagy (LC3 and p62 expression) and GDNF expression. Adeno-associated virus (AAV)-GDNF was microinjected into the basal forebrain to see whether increased GDNF expression could reverse sleep deprivation-induced changes in pain duration and cholinergic neuron apoptosis and autophagy. Cholinergic neurons were further depleted by mu p75-SAP to examine whether the pain-prolonging effects of sleep deprivation still exist. RESULTS:Perioperative sleep deprivation enhanced pain sensation and prolonged pain duration in SMIR mice, which was accompanied by decreased cholinergic neuron activity and GDNF expression, increased apoptosis, and autophagy dysfunction in the substantia innominata (SI), magnocellular preoptic nucleus (MCPO), and horizontal diagonal band Broca (HDB) (hereafter lateral basal forebrain). Normalizing cholinergic neuron GDNF expression by AAV-GDNF in the lateral basal forebrain inhibited apoptosis and autophagy dysfunction and mitigated sleep deprivation-induced pain maintenance. Mice with selective lesion of lateral basal forebrain cholinergic neurons were resistant to the pain-enhancing and prolonging effects of sleep deprivation and the pain-alleviating effects of AAV-GDNF therapy. CONCLUSIONS:Perioperative sleep deprivation promotes chronicity of postsurgical pain possibly through decreasing basal forebrain GDNF signaling and causing cholinergic neuronal apoptosis and autophagy dysfunction.

BackgroundIonizing radiation (IR), including radiotherapy, can exert lasting harm on living organisms. While liposaccharide (LPS) offers resistance to radiation damage, it also induces toxic responses. Thankfully, an LPS analogue called N-formylmethionine-leucyl-phenylalanine (fMLP) holds the potential to mitigate this toxicity, offering hope for radiation protection.MethodsSurvival of C57BL/6 mice exposed to IR after administration with fMLP/LPS/WR-2721 or saline was recorded. Cell viability and apoptosis assay of bone marrow (BMC), spleen and small intestinal epithelial (HIECs) cells were tested by Cell Counting Kit-8 (CCK-8) and flow cytometry assay. Tissue damage was evaluated by Hematoxilin and Eosin (H&E), Ki-67, and TUNEL staining. RNA sequencing was performed to reveal potential mechanisms of fMLP-mediated radiation protection. Flow cytometry and western blot were performed to verify the radiation protection mechanism of fMLP on the cell cycle.ResultsThe survival rates of C57BL/6 mice exposed to ionizing radiation after administering fMLP increased. fMLP demonstrated low toxicity in vitro and in vivo, maintaining cell viability and mitigating radiation-induced apoptosis. Moreover, it protected against tissue damage in the hematopoietic and intestinal system. RNA sequencing shed light on fMLP's potential mechanism, suggesting its role in modulating innate immunity and cell cycling. This was evidenced by its ability to reverse radiation-induced G2/M phase arrests in HIECs.ConclusionfMLP serves as a promising radioprotective agent, preserving cells and radiosensitive tissues from IR. Through its influence on the cell cycle, particularly reversing radiation-induced arrest in G2/M phases, fMLP offers protection against IR's detrimental effects.

The combination of thoracic radiotherapy and immune checkpoint inhibitors (ICIs) has emerged as a novel treatment approach for malignant tumors. However, it is important to consider the potential exacerbation of lung injury associated with this treatment modality. The neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, holds promise as a non-invasive indicator for assessing the toxicity of this combination therapy. To investigate this further, a study involving 80 patients who underwent thoracic radiotherapy in conjunction with ICIs was conducted. These patients were divided into two groups: The concurrent therapy group and the sequential therapy group. A logistic regression analysis was conducted to ascertain risk factors for grade >= 2 pneumonitis. Following propensity score matching, the NLR values were examined between the concurrent group and the sequential group to evaluate any disparity. A mouse model of radiation pneumonitis was established, and ICIs were administered at varying time points. The morphological evaluation of lung injury was conducted using H&E staining, while the NLR values of peripheral blood were detected through flow cytometry. Logistic regression analysis revealed that radiation dosimetric parameters (mean lung dose, total dose and V20), the inflammatory index NLR at the onset of pneumonitis, and treatment sequences (concurrent or sequential) were identified as independent predictors of grade >= 2 treatment-related pneumonitis. The results of the morphological evaluation indicated that the severity of lung tissue injury was greater in cases where programmed cell death protein 1 (PD-1) blockade was administered during thoracic radiotherapy, compared with cases where PD-1 blockade was administered 14 days after radiotherapy. Moreover, the present study demonstrated that the non-invasive indicator known as the NLR has the potential to accurately reflect the aforementioned injury.

Purpose: UVB exposure accelerates skin aging and age-associated pigmentation, but their relationship remains unclear. UVB induces premature senescence and melanin production within melanocytes, accompanied by the up-regulation of p53 and cellular tyrosinase (TYR). As a tumor suppressor gene, p53 can keep the genome intact by modulating cell apoptosis and growth arrest during DNA injury. P53 also relates to age-associated pigmentation, directly or indirectly regulating pigment-related gene expression. Melatonin effectively regulates tyrosinase activity and resists aging. This study focused on the regulation of p53 on TYR to understand the association between premature senescence and senescence-associated pigmentation and determine the mechanism behind melatonin affecting UVB stimulated melanin production.Methods: Primary melanocytes were extracted and identified from the male foreskin. The primary melanocytes were transduced using lentivirus pLKD-CMV-EGFP-2A-Puro-U6-TYR to knock down TYR expression. The melanin content was determined using the NaOH method, the oxidation of 3,4-Dihydroxy-L-phenylalanine (L-DOPA) into dopachrome to determine TYR activity, and Western blotting was used to detect the level of TYR protein. After being pretreated with Nutlin-3 or PFT-α to up or down-regulate p53 levels or melatonin for 12 h, primary melanocytes were under UVB irradiation at 80 mJ/cm2. The senescence-associated beta-galactosidase (SA-β-gal) kit analyzed premature senescence. At the same time, the level of p53, p-p53, and TYR protein were detected using the automated capillary electrophoresis western analysis in melanocytes at 72 h after UVB irradiation. Wild-type and TYR (–/–) or TYR (+/–) knockout C57BL/6J mice were used to verify the regulatory role of TYR on melanin synthesis in vivo . Moreover, the effect of melatonin on skin erythema and pigmentation induced by UVB irradiation was illustrated in vivo.Results: Primary melanocytes showed a deep black color after L-DOPA staining, higher TYR protein, and mRNA expression. Tyrosinase activity and melanin levels induced by UVB irradiation were significantly alleviated after being infected with pLKD-CMV-EGFP-2A-Puro-U6-TYR (P <0.05). Premature senescence, tyrosinase activity, and melanin levels were increased under UVB irradiation induction. Furthermore, there was a dramatic increase following the Nutlin-3 treatment while significantly inhibited after being treated with PFT-α (P <0.05) in the primary melanocytes. Melatonin inhibited UVB-induced premature senescence, associated with decreased p53 level and phosphorylation on serine-15 position, decreased UVB-induced tyrosinase activity and melanin levels, and reduced TYR expression. TYR (–/–) knockout mice were recognized through white hair colors, whiskers, paws, and pigment loss in the eyes. The tyrosinase activity and melanin levels in the whiskers follicles of TYR (–/–) knockout mice were also significantly decreased (P <0.05) relative to the wild-type (WT) counterparts. Skin erythema and melanin pigmentation induced by UVB irradiation were reduced in the dorsal and ear skin of C57BL/6J mice topically pretreated with 2.5% melatonin.Conclusion: Melanin synthesis induced by UVB irradiation is dependent on TYR in primary melanocytes and C57BL/6J mice. Moreover, p53 links the UVB irradiation-induced premature senescence and senescence-associated pigmentation in the primary melanocytes, and directly regulates TYR in primary mel

Study Objectives This study verified that sleep deprivation before and after skin/muscle incision and retraction (SMIR) surgery increased the risk of chronic pain and investigated the underlying roles of microglial voltage-dependent anion channel 1 (VDAC1) signaling. Methods Adult mice received 6 hours of total sleep deprivation from 1 day prior to SMIR until the third day after surgery. Mechanical and heat-evoked pain was assessed before and within 21 days after surgery. Microglial activation and changes in VDAC1 expression and oligomerization were measured. Minocycline was injected to observe the effects of inhibiting microglial activation on pain maintenance. The VDAC1 inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and oligomerization inhibitor VBIT-4 were used to determine the roles of VDAC1 signaling on microglial adenosine 5' triphosphate (ATP) release, inflammation (IL-1β and CCL2), and chronicity of pain. Results Sleep deprivation significantly increased the pain duration after SMIR surgery, activated microglia, and enhanced VDAC1 signaling in the spinal cord. Minocycline inhibited microglial activation and alleviated sleep deprivation-induced pain maintenance. Lipopolysaccharide (LPS)-induced microglial activation was accompanied by increased VDAC1 expression and oligomerization, and more VDAC1 was observed on the cell membrane surface compared with control. DIDS and VBIT-4 rescued LPS-induced microglial ATP release and IL-1β and CCL2 expression. DIDS and VBIT-4 reversed sleep loss-induced microglial activation and pain chronicity in mice, similar to the effects of minocycline. No synergistic effects were found for minocycline plus VBIT-4 or DIDS. Conclusions Perioperative sleep deprivation activated spinal microglia and increases the risk of chronic postsurgical pain in mice. VDAC1 signaling regulates microglial activation-related ATP release, inflammation, and chronicity of pain.

STUDY OBJECTIVES This study verified that sleep deprivation before and after skin/muscle incision and retraction (SMIR) surgery increased the risk of chronic pain and investigated the underlying roles of microglial VDAC1 signaling. METHODS Adult mice received six hours of total sleep deprivation from one day prior to SMIR until the third days after surgery. Mechanical and heat-evoked pain was assessed before and within 21 days after surgery. Microglial activation and changes of VDAC1 expression and oligomerization were measured. Minocycline was injected to observe the effects of inhibiting microglial activation on pain maintenance. The VDAC1 inhibitor DIDS and oligomerization inhibitor VBIT-4 were used to determine the roles of VDAC1 signaling on microglial ATP release, inflammation (IL-1β and CCL2), and chronicity of pain. RESULTS Sleep deprivation significantly increased the pain duration after SMIR surgery, activated microglia and enhanced VDAC1 signaling in the spinal cord. Minocycline inhibited microglial activation and alleviated sleep deprivation-induced pain maintenance. Lipopolysaccharide (LPS)-induced microglial activation was accompanied by increased VDAC1 expression and oligomerization, and more VDAC1 was observed on the cell membrane surface compared with control. DIDS and VBIT-4 rescued LPS-induced microglial ATP release and IL-1β and CCL2 expression. DIDS and VBIT-4 reversed sleep loss-induced microglial activation and pain chronicity in mice, similar to the effects of minocycline. No synergistic effects were found for minocycline plus VBIT-4 or DIDS. CONCLUSIONS Perioperative sleep deprivation activated spinal microglia and increases the risk of chronic postsurgical pain in mice. VDAC1 signaling regulates microglial activation-related ATP release, inflammation, and chronicity of pain.

AIMS:To verify the hypothesis that an enriched environment (EE) alleviates sleep deprivation-induced fear memory impairment by modulating the basal forebrain (BF) PIEZO1/calpain/autophagy pathway.METHODS:Eight-week-old male mice were housed in a closed, isolated environment (CE) or an EE, before 6-h total sleep deprivation. Changes in fear memory after sleep deprivation were observed using an inhibitory avoidance test. Alterations in BF PIEZO1/calpain/autophagy signaling were detected. The PIEZO1 agonist Yoda1 or inhibitor GsMTx4, the calpain inhibitor PD151746, and the autophagy inducer rapamycin or inhibitor 3-MA were injected into the bilateral BF to investigate the pathways involved in the memory-maintaining role of EE in sleep-deprived mice.RESULTS:Mice housed in EE performed better than CE mice in short- and long-term fear memory tests after sleep deprivation. Sleep deprivation resulted in increased PIEZO1 expression, full-length tropomyosin receptor kinase B (TrkB-FL) degradation, and autophagy, as reflected by increased LC3 II/I ratio, enhanced p62 degradation, increased TFEB expression and nuclear translocation, and decreased TFEB phosphorylation. These molecular changes were partially reversed by EE treatment. Microinjection of Yoda1 or rapamycin into the bilateral basal forebrain induced excessive autophagy and eliminated the cognition-protective effects of EE. Bilateral basal forebrain microinjection of GsMTx4, PD151746, or 3-MA mimicked the cognitive protective and autophagy inhibitory effects of EE in sleep-deprived mice.CONCLUSIONS:EE combats sleep deprivation-induced fear memory impairments by inhibiting the BF PIEZO1/calpain/autophagy pathway.

Radiation-induced intestinal injury (RIII) occurs after high doses of radiation exposure. RIII restricts the therapeutic efficacy of radiotherapy in cancer and increases morbidity and mortality in nuclear disasters. Currently, there is no approved agent for the prevention or treatment of RIII. Here, we reported that the disulfiram, an FDA-approved alcohol deterrent, prolonged the survival in mice after lethal irradiation. Pretreatment with disulfiram inhibited proliferation within 24 h after irradiation, but improved crypt regeneration at 3.5 days post-irradiation. Mechanistically, disulfiram promoted Lgr5+ intestinal stem cells (ISCs) survival and maintained their ability to regenerate intestinal epithelium after radiation. Moreover, disulfiram suppresses DNA damage accumulation, thus inhibits aberrant mitosis after radiation. Unexpectedly, disulfiram treatment did not inhibit crypt cell apoptosis 4 h after radiation and the regeneration of crypts from PUMA-deficient mice after irradiation was also promoted by disulfiram. In conclusion, our findings demonstrate that disulfiram regulates the DNA damage response and survival of ISCs through affecting the cell cycle. Given its radioprotective efficacy and decades of application in humans, disulfiram is a promising candidate to prevent RIII in cancer therapy and nuclear accident.

过氧化物酶体增殖物活化受体(peroxisome proliferator activatived receptors,PPARs)是核受体超家族成员,包括PPARα、PPARδ和PPARγ3种亚型,他们在不同组织中表达,其中PPARγ在脂肪组织、心脏、 肠道和免疫细胞中存在,在脂肪合成过程中起着关键作用.PPARγ具有抗氧化作用,通过调控Nrf2信号通路、 内皮型NOS(eNOS)和诱导型NOS(iNOS)表达以及其他相关信号通路发挥作用.辐射诱导的氧化应激是引起细胞水平和全身水平损伤的主要因素,由于PPARγ具有抗氧化应激的能力,有望成为辐射防护和辐射治疗的有效靶点.

Radiotherapy of abdominal and pelvic tumors almost inevitably injures the intestine by oxidative stress and causes inflammation. Regrettably, traditional radioprotective agents for irradiation (IR) induced intestinal injury suffer from challenges such as poor solubility, unsatisfactory bioactivity and undesired adverse reactions, which significantly limit their usefulness. Polydopamine nanoparticles (PDA-NPs) have shown promising potential in scavenging reactive oxygen species (ROS) and suppressing inflammation. In this study, PDA-NPs were prepared by a simple method and their physical properties were characterized. Mice received two doses of PDA-NPs by oral gavage 22 h apart, and were irradiated with X-rays 2 h after the last gavage. The protective effect of PDA-NPs and possible mechanisms of protection against IR-induced intestinal injury were explored. The results showed that PDA-NPs were spherical and well dispersed, with good shape uniformity, compact structure, good colloid dispersion stability, concentration-dependent light absorption, and accurate quantification. Importantly, PDA-NPs reduced mortality and prolonged the average survival time of mice after IR. Furthermore, PDA-NPs protected mice from IR-induced injury to crypt-villus units and maintained intestinal barrier function in the intestine. In particular, PDA-NPs significantly inhibited the depletion of Lgr5+ intestinal stem cells (ISCs) and promoted cell regeneration after IR, which indicated that the regeneration ability of ISCs was maintained and the repair of intestinal structure and function was promoted. Finally, PDA-NPs significantly suppressed the apoptosis, inflammatory pyroptosis and DNA damage of intestinal cells induced by ionizing radiation. Altogether, our study suggested that PDA-NPs may have great potential in protecting the intestines from ionizing radiation damage.

为减少乳清蛋白用量,用马铃薯蛋白替代乳清蛋白质量的一半制备了热诱导凝胶.通过色度、质构、水分分布、流变考察了总蛋白质量浓度(40～80 g/L)对于复合凝胶物理性质的影响.结果表明,复合凝胶最低成胶质量浓度为50 g/L(其中乳清蛋白质量浓度为25 g/L),与乳清蛋白最低成胶质量浓度80 g/L相比,乳清蛋白用量减少了68.8％.总蛋白质量浓度从50 g/L提高到80 g/L时,复合凝胶偏黄,硬度和弹性分别增加了5.28倍和5.90％,但束缚水含量降低了3.51％;储能模量(G')显示较弱的频率依赖性.蛋白质量浓度为80 g/L的复合凝胶孔隙尺寸小,具有由颗粒聚集体组成的均一致密网络结构,因而具有较高的G'.复合凝胶中β-折叠和β-转角结构约占蛋白二级结构的70％.维持复合凝胶结构的作用力中氢键和疏水相互作用的贡献高于二硫键.

Recently, Toll-like receptors (TLRs) have been extensively studied in radiation damage, but the inherent defects of high toxicity and low efficacy of most TLR ligands limit their further clinical transformation. CRX-527, as a TLR4 ligand, has rarely been reported to protect against radiation. We demonstrated that CRX-527 was safer than LPS at the same dose in vivo and had almost no toxic effect in vitro. Administration of CRX-527 improved the survival rate of total body irradiation (TBI) to 100% in wild-type mice but not in TLR4-/- mice. After TBI, hematopoietic system damage was significantly alleviated, and the recovery period was accelerated in CRX-527-treated mice. Moreover, CRX-527 induced differentiation of HSCs and the stimulation of CRX-527 significantly increased the proportion and number of LSK cells and promoted their differentiation into macrophages, activating immune defense. Furthermore, we proposed an immune defense role for hematopoietic differentiation in the protection against intestinal radiation damage, and confirmed that macrophages invaded the intestines through peripheral blood to protect them from radiation damage. Meanwhile, CRX-527 maintained intestinal function and homeostasis, promoted the regeneration of intestinal stem cells, and protected intestinal injury from lethal dose irradiation. Furthermore, After the use of mice, we found that CRX-527 had no significant protective effect on the hematopoietic and intestinal systems of irradiated TLR4-/- mice. in conclusion, CRX-527 induced differentiation of HSCs protecting the intestinal epithelium from radiation damage.