PC4-mediated Ku complex PARylation facilitates NHEJ-dependent DNA damage repair.

Radiotherapy is one of the mainstay treatments for hepatocellular carcinoma (HCC). However, a substantial number of patients with HCC develop radioresistance and eventually suffer from tumor progression or relapse, which is a major impediment to the use of radiotherapy. Therefore, elucidating the mechanisms underlying radioresistance and identifying novel therapeutic targets to improve patient prognosis are important in HCC management. In this study, using in vitro and in vivo models, laser microirradiation and live cell imaging methods, and coimmunoprecipitation assays, we report that a DNA repair enhancer, human positive cofactor 4 (PC4), promotes nonhomologous end joining-based DNA repair and renders HCC cells resistant to radiation. Mechanistically, PC4 interacts with poly (ADP-ribose) polymerase 1 and directs Ku complex PARylation, resulting in the successful recruitment of the Ku complex to damaged chromatin and increasing the efficiency of nonhomologous end joining repair. Clinically, PC4 is highly expressed in tumor tissues and is correlated with poor prognosis in patients with HCC. Taken together, our data suggest that PC4 is a DNA repair driver that can be targeted to radiosensitize HCC cells.

Senescent fibroblast facilitates re-epithelization and collagen deposition in radiation-induced skin injury through IL-33-mediated macrophage polarization.

BACKGROUND: The need for radiotherapy among the elderly rises with increasing life expectancy and a corresponding increase of elderly cancer patients. Radiation-induced skin injury is one of the most frequent adverse effects in radiotherapy patients, severely limiting their life quality. Re-epithelialization and collagen deposition have essential roles in the recovery of skin injuries induced by high doses of ionizing radiation. At the same time, radiation-induced senescent cells accumulate in irradiated tissues. However, the effects and mechanisms of senescent cells on re-epithelialization and collagen deposition in radiation-induced skin injury have not been fully elucidated. RESULTS: Here, we identified a role for a population of senescent cells expressing p16 in promoting re-epithelialization and collagen deposition in radiation-induced skin injury. Targeted ablation of p16+ senescent cells or treatment with Senolytics resulted in the disruption of collagen structure and the retardation of epidermal coverage. By analyzing a publicly available single-cell sequencing dataset, we identified fibroblasts as a major contributor to the promotion of re-epithelialization and collagen deposition in senescent cells. Notably, our analysis of publicly available transcriptome sequencing data highlighted IL-33 as a key senescence-associated secretory phenotype produced by senescent fibroblasts. Neutralizing IL-33 significantly impedes the healing process. Finally, we found that the effect of IL-33 was partly due to the modulation of macrophage polarization. CONCLUSIONS: In conclusion, our data suggested that senescent fibroblasts accumulated in radiation-induced skin injury sites participated in wound healing mainly by secreting IL-33. This secretion regulated the local immune microenvironment and macrophage polarization, thus emphasizing the importance of precise regulation of senescent cells in a phased manner.

The stress-responsive gene ATF3 drives fibroblast activation and collagen production through transcriptionally activating TGF-ß receptor â ¡ in skin wound healing.

Skin wound is an emerging health challenge on account of the high-frequency trauma, surgery and chronic refractory ulcer. Further study on the disease biology will help to develop new effective approaches for wound healing. Here, we identified a wound-stress responsive gene, activating transcription factor 3 (ATF3), and then investigated its biological action and mechanism in wound healing. In the full-thickness skin wound model, ATF3 was found to promote fibroblast activation and collagen production, resulted in accelerated wound healing. Mechanically, ATF3 transcriptionally activated TGF-ß receptor Ⅱ via directly binding to its specific promoter motif, followed by the enhanced TGF-ß/Smad pathway in fibroblasts. Moreover, the increased ATF3 upon skin injury was partly resulted from hypoxia stimulation with Hif-1α dependent manner. Altogether, this work gives novel insights into the biology and mechanism of stress-responsive gene ATF3 in wound healing, and provides a potential therapeutic target for treatment.

Near-infrared fluorophore IR-61 delays postovulatory aging of mouse oocytes through suppressing oxidative stress mediated by mitochondrial protection.

Postovulatory aging can trigger deterioration of oocyte quality and subsequent embryonic development, and thus reduce the success rates of assisted reproductive technology (ART). The molecular mechanisms underlying postovulatory aging, and preventative strategies, remain to be explored. The near-infrared fluorophore IR-61, a novel heptamethine cyanine dye, has the potential for mitochondrial targeting and cell protection. In this study, we found that IR-61 accumulated in oocyte mitochondria and reduced the postovulatory aging-induced decline in mitochondrial function, including mitochondrial distribution, membrane potential, mtDNA number, ATP levels, and mitochondrial ultrastructure. In addition, IR-61 rescued postovulatory aging-caused oocyte fragmentation, defects in spindle structure, and embryonic developmental potential. RNA sequencing analysis indicated that the postovulatory aging-induced oxidative stress pathway might be inhibited by IR-61. We then confirmed that IR-61 decreased the levels of reactive oxygen species and MitoSOX, and increased GSH content in aged oocytes. Collectively, the results indicate that IR-61 may prevent postovulatory aging by rescuing oocyte quality, promoting successful rate in ART procedure.

Altered EEG Microstates Dynamics in Individuals with Subthreshold Depression When Generating Negative Future Events.

Negative bias in prospection may play a crucial role in driving and maintaining depression. Recent research suggests abnormal activation and functional connectivity in regions of the default mode network (DMN) during future event generation in depressed individuals. However, the neural dynamics during prospection in these individuals remain unknown. To capture network dynamics at high temporal resolution, we employed electroencephalogram (EEG) microstate analysis. We examined microstate properties during both positive and negative prospection in 35 individuals with subthreshold depression (SD) and 35 controls. We identified similar sets of four canonical microstates (A-D) across groups and conditions. Source analysis indicated that each microstate map partially overlapped with a subsystem of the DMN (A: verbal; B: visual-spatial; C: self-referential; and D: modulation). Notably, alterations in EEG microstates were primarily observed in negative prospection of individuals with SD. Specifically, when generating negative future events, the coverage, occurrence, and duration of microstate A increased, while the coverage and duration of microstates B and D decreased in the SD group compared to controls. Furthermore, we observed altered transitions, particularly involving microstate C, during negative prospection in the SD group. These altered dynamics suggest dysconnectivity between subsystems of the DMN during negative prospection in individuals with SD. In conclusion, we provide novel insights into the neural mechanisms of negative bias in depression. These alterations could serve as specific markers for depression and potential targets for future interventions.

Cordycepin delays postovulatory aging of oocytes through inhibition of maternal mRNAs degradation via DCP1A polyadenylation suppression.

Postovulatory aging leads to the decline in oocyte quality and subsequent impairment of embryonic development, thereby reducing the success rate of assisted reproductive technology (ART). Potential preventative strategies preventing oocytes from aging and the associated underlying mechanisms warrant investigation. In this study, we identified that cordycepin, a natural nucleoside analogue, promoted the quality of oocytes aging in vitro, as indicated by reduced oocyte fragmentation, improved spindle/chromosomes morphology and mitochondrial function, as well as increased embryonic developmental competence. Proteomic and RNA sequencing analyses revealed that cordycepin inhibited the degradation of several crucial maternal proteins and mRNAs caused by aging. Strikingly, cordycepin was found to suppress the elevation of DCP1A protein by inhibiting polyadenylation during postovulatory aging, consequently impeding the decapping of maternal mRNAs. In humans, the increased degradation of DCP1A and total mRNA during postovulatory aging was also inhibited by cordycepin. Collectively, our findings demonstrate that cordycepin prevents postovulatory aging of mammalian oocytes by inhibition of maternal mRNAs degradation via suppressing polyadenylation of DCP1A mRNA, thereby promoting oocyte developmental competence.

Intravesical IR-780 instillation prevents radiation cystitis by protecting urothelial integrity.

PURPOSE: To explore an efficient preventive strategy for radiation cystitis. METHODS: We instilled IR-780 into the bladders of rats 1 h before bladder irradiation, and its bio-distribution was observed at different times. Bladders were then examined for pathogenic alterations and inflammation levels by day 3 and week 12 postirradiation, and the functional characteristics of the bladder were tested via cystometry by week 12. Human uroepithelial sv-huc-1 cells were used to determine the effect of IR-780 on cell viability, regardless of irradiation. We measured the intracellular levels of oxidative stress, DNA damage, apoptosis proportion, and the expression of antioxidant proteases and apoptotic caspases in IR-780 pretreated cells after radiation. RESULTS: IR-780 is localized in the urothelium after intravesical instillation in vivo. Ionizing radiation could induce acute impairment of the bladder urothelium and inflammation in the bladder on day 3. Fibrosis of the irradiated bladder progressed and eventually affected voiding function at 12 weeks. Treatment with IR-780 before irradiation ameliorated these changes. In vitro, IR-780 protected against cell viability and apoptosis of sv-huc-1 cells after irradiation. Additionally, IR-780 may assist in eliminating reactive oxygen species and repairing irradiation-induced DNA damage. CONCLUSION: Our data indicate that IR-780 can be used before irradiation to prevent acute urinary mucosal injury and late bladder dysfunction. Moreover, early urothelial impairment plays a significant role in radiation cystitis development.

Molecular detection of spotted fever group rickettsiae in hedgehogs (Erinaceus amurensis) and hedgehog-attached ticks in Xuyi County, Southeast China.

Tick-borne diseases like Rickettsia, Anaplasma and Ehrlichia are widespread infectious zoonoses that threaten the health of both humans and animals worldwide. Ticks and their hosts, such as hedgehogs, can play a crucial role in transmitting tick-borne diseases and the cycle of Rickettsia. To investigate the presence and identity of Rickettsia in hedgehogs and hedgehog-attached ticks in Xuyi County, Southeast China, 114 ticks were collected from 45 hedgehogs captured totally. Via morphological and molecular methods, all these ticks were identified as two species: Haemaphysalis flava (110/114, 96.5%) and Haemaphysalis longicornis (4/114, 3.5%). Rickettsia spp. were genotypically characterized by PCR targeting rrs, gltA, ompA, ompB, and sca4 gene fragments. The prevalence of spotted fever group rickettsiae (SFGR) infection found in hedgehogs and ticks was 17.8% (8/45) and 78.1% (89/114), respectively. Phylogenetic analyses demonstrated that those Rickettsia spp. belong to two species: Rickettsia heilongjiangensis (R. heilongjiangensis XY-1) and a potential new species, Candidatus Rickettsia xuyiensis XY-2. The present study gave the first evidence of R. heilongjiangensis and Candidatus R. xuyiensis in ticks and hedgehogs of Southeast China. Our findings suggest that hedgehogs might be involved in the natural transmission cycle of Rickettsia species.

Knockdown of PC4 increases chemosensitivity of Oxaliplatin in triple negative breast cancer by suppressing mTOR pathway.

As a multifunctional nuclear protein, the human positive cofactor 4 (PC4) is highly expressed in various tumors including breast cancer and has potential roles in cancer development and progression. However, the functional signatures and molecular mechanisms of PC4 in triple negative breast cancer (TNBC) progression and chemotherapeutic response are still unknown. In this study, we found that PC4 is significantly upregulated in TNBC cells compared with non-TNBC cells, implying its potential role in TNBC. Then, in vivo and in vitro studies revealed that knockdown of PC4 increased chemosensitivity of Oxaliplation (Oxa) in TNBC by suppressing mTOR pathway. Therefore, our findings demonstrated the signatures and molecular mechanisms of PC4 in TNBC chemotherapeutic response, and indicated that PC4 might be a promising therapeutic target for TNBC.

Rapamycin Induced Autophagy Inhibits Inflammation-Mediated Endplate Degeneration by Enhancing Nrf2/Keap1 Signaling of Cartilage Endplate Stem Cells.

Cartilage endplate (CEP) calcification inhibits the transport of metabolites and nutrients in the intervertebral disk and is an important initiating factor of intervertebral disk degeneration. However, the mechanisms governing CEP degeneration have not been thoroughly elucidated. In this study, we established a mouse CEP degeneration model and showed that autophagy insufficiency caused the degeneration of CEP. We found that the inflammatory cytokine tumor necrosis factor-α (TNF-α) increased the level of intracellular reactive oxygen species (ROS) and caused cell senescence and osteogenic differentiation of cartilage endplate stem cells (CESCs), whereas rapamycin-induced autophagy protected CESCs from TNF-α-induced oxidative stress and cell senescence. Furthermore, rapamycin-induced autophagy helped CESCs maintain the chondrogenic properties and inhibited extracellular matrix protease expression and osteogenic differentiation. Further study revealed that autophagy activated by rapamycin or inhibited by chloroquine influenced the expression and nuclear translocation of Nrf2, thereby controlling the expression of antioxidant proteins and the scavenging of ROS. Taken together, the results indicate that rapamycin-induced autophagy enhances Nrf2/Keap1 signaling and promotes the expression of antioxidant proteins, thereby eliminating ROS, alleviating cell senescence, reducing the osteogenic differentiation of CESCs, and ultimately protecting CEPs from chronic inflammation-induced degeneration. Stem Cells 2019;37:828-840.

Transcriptional positive cofactor 4 promotes breast cancer proliferation and metastasis through c-Myc mediated Warburg effect.

BACKGROUND: The human positive cofactor 4 (PC4) is initially identified as a transcriptional cofactor and has an important role in embryonic development and malignant transformation. However, the clinical significance and the molecular mechanisms of PC4 in breast cancer development and progression are still unknown. METHODS: We investigated PC4 expression in 114 cases of primary breast cancer and matched normal breast tissue specimens, and studied the impact of PC4 expression as well as the molecular mechanisms of this altered expression on breast cancer growth and metastasis both in vitro and in vivo. RESULTS: PC4 was significantly upregulated in breast cancer and high PC4 expression was positively correlated with metastasis and poor prognosis of patients. Gene set enrichment analysis (GSEA) demonstrated that the gene sets of cell proliferation and Epithelial-Mesenchymal Transition (EMT) were positively correlated with elevated PC4 expression. Consistently, loss of PC4 markedly inhibited the growth and metastasis of breast cancer both in vitro and in vivo. Mechanistically, PC4 exerted its oncogenic functions by directly binding to c-Myc promoters and inducing Warburg effect. CONCLUSIONS: Our study reveals for the first time that PC4 promotes breast cancer progression by directly regulating c-Myc transcription to promote Warburg effect, implying a novel therapeutic target for breast cancer.

Identification of a fluorescent small-molecule enhancer for therapeutic autophagy in colorectal cancer by targeting mitochondrial protein translocase TIM44.

OBJECTIVE: As the modulation of autophagic processes can be therapeutically beneficial to cancer treatment, the identification of novel autophagic enhancers is highly anticipated. However, current autophagy-inducing anticancer agents exert undesired side effects owing to their non-specific biodistribution in off-target tissues. This study aims to develop a multifunctional agent to integrate cancer targeting, imaging and therapy and to investigate its mechanism. DESIGN: A series of mitochondria-targeting near-infrared (NIR) fluorophores were synthesised, screened and identified for their autophagy-enhancing activity. The optical properties and biological effects were tested both in vitro and in vivo. The underlying mechanism was investigated using inhibitors, small interfering RNA (siRNA), RNA sequencing, mass spectrometry and human samples. RESULTS: We have screened and identified a new NIR autophagy-enhancer, IR-58, which exhibits significant tumour-selective killing effects. IR-58 preferentially accumulates in the mitochondria of colorectal cancer (CRC) cells and xenografts, a process that is glycolysis-dependent and organic anion transporter polypeptide-dependent. IR-58 kills tumour cells and induces apoptosis via inducing excessive autophagy, which is mediated through the reactive oxygen species (ROS)-Akt-mammalian target of rapamycin (mTOR) pathway. RNA sequencing, mass spectrometry and siRNA interference studies demonstrate that translocase of inner mitochondrial membrane 44 (TIM44)-superoxide dismutase 2 (SOD2) pathway inhibition is responsible for the excessive ROS, autophagy and apoptosis induced by IR-58. TIM44 expression correlates positively with CRC development and poor prognosis in patients. CONCLUSIONS: A novel NIR small-molecule autophagy-enhancer, IR-58, with mitochondria-targeted imaging and therapy capabilities was developed for CRC treatment. Additionally, TIM44 was identified for the first time as a potential oncogene, which plays an important role in autophagy through the TIM44-SOD2-ROS-mTOR pathway.

The PPARγ agonist rosiglitazone sensitizes the BH3 mimetic (-)-gossypol to induce apoptosis in cancer cells with high level of Bcl-2.

The BH3 mimetic (-)-gossypol (-)-G has shown promising efficacy to kill several kinds of cancer cells or potentiate current chemotherapeutics. But it induces limited apoptosis in cancer cells with high level of Bcl-2. The nuclear receptor PPARγ and its agonist rosiglitazone can suppress various malignancies. More importantly, rosiglitazone is able to enhance the anti-tumor effects of chemotherapy drugs such as carboplatin and tyrosine kinase inhibitors. In this study, we for the first time demonstrated that rosiglitazone could sensitize (-)-G to induce apoptosis in cancer cells with high level of Bcl-2. Furthermore, we found that (-)-G increased the mRNA level and protein stability of Mcl-1, which weakened the pro-apoptotic effect of (-)-G. Rosiglitazone attenuated the (-)-G-induced Mcl-1 stability through decreasing JNK phosphorylation. Additionally, rosiglitazone upregulated dual-specificity phosphatase 16 (DUSP16), leading to a reduction of (-)-G-triggered JNK phosphorylation. Animal experiments showed that rosiglitazone could sensitize (-)-G to repress the growth of cancer cells with high level of Bcl-2 in vivo. Taken together, our results suggest that the PPARγ agonists may enhance the therapeutic effect of BH3 mimetics in cancers with high level of Bcl-2 through regulating the DUSP16/JNK/Mcl-1 singling pathway. This study may provide novel insights into the cancer therapeutics based on the combination of PPARγ agonists and BH3 mimetics.

Involvement of RNA helicase p68 in skin wound healing process in rats.

PURPOSE: RNA helicase p68 plays an important role in organ development and maturation through tuning cell proliferation. However, the character and role of p68 in the whole wound healing process need more study. METHODS: First, we characterize expression of p68 in normal rat skin development postnatal. Then, we assayed dynamic change of p68 in rat skin from different stage after injury, and explored the role of p68 in proliferation and migration of three types of wound healing related cells. RESULTS: p68 was down-regulated during skin developmental and maturation process, up-regulated after wound, peaked on day 14 and then significantly decreased. Wound fluid enhanced wound healing related cell proliferation and up-regulated expression of p68. Conversely, reducing p68 expression by RNA interference resulted in significantly slower proliferation and migration. CONCLUSION: Our results define an important role of RNA helicase p68 in skin wound healing process.

Near infrared in vivo flow cytometry for tracking fluorescent circulating cells.

The in vivo flow cytometry (IVFC) is now a powerful technique in biomedical research, especially for tracking specific cells in circulatory system. The current fluorescence-based IVFC is limited to visible spectrum, while near infrared (NIR) dyes have their advantages, such as deeper penetration, less absorption and less scattering for NIR fluorescence. Here, using an NIR in vivo flow cytometer with a 785 nm laser excitation, the measurement of fluorescent dye IR-780 labeled circulating cells is demonstrated. Representative peaks corresponding to NIR fluorescent circulating cells are detected and quantified. In addition, blood flow information, including the blood flow velocity and flow volume per unit time, is obtained. By simultaneous detection of IR-780 and enhanced green fluorescent protein (EGFP) signals from dual labeled cells, the IR-780 is shown to be a suitable fluorescent dye for multicolor detection by IVFC, including NIR. Thus, the IVFC is extended to the NIR range and shows potential application in biomedical research.

NEAR-INFRARED DYE IR-780 ALLEVIATES HEMATOPOIETIC SYSTEM DAMAGE BY PROMOTING HEMATOPOIETIC STEM CELLS INTO QUIESCENCE.

ABSTRACT: Potential radiation exposure is a general concern, but there still lacks radioprotective countermeasures. Here, we found a small molecular near-infrared dye IR-780, which promoted hematopoietic stem cells (HSCs) into quiescence to resist stress. When mice were treated with IR-780 before stress, increased HSC quiescence and better hematopoietic recovery were observed in mice in stress conditions. However, when given after radiation, IR-780 did not show obvious benefit. Transplantation assay and colony-forming assay were carried out to determine self-renewal ability and repopulation capacity of HSCs. Furthermore, IR-780 pretreatment reduced the generation of reactive oxygen species (ROS) and DNA damage in HSCs after radiation. In homeostasis, the percentage of Lineage - , Sca-1 + , and c-Kit + cells and long-term HSCs (LT-HSCs) were improved, and more HSCs were in G0 state after administration of IR-780. Further investigations showed that IR-780 selectively accumulated in mitochondria membrane potential high LT-HSCs (MMP-high LT-HSCs). Finally, IR-780 promoted human CD34 + HSC reconstruction ability in NOD-Prkdc scid Il2rg null mice after transplantation and improved repopulation capacity in vitro culture. Our research showed that IR-780 selectively entered MMP-high LT-HSCs and promoted them into dormancy, thus reducing hematopoietic injury and improving regeneration capacity. This novel approach might hold promise as a potential countermeasure for radiation injury.

PC4 promotes bladder cancer progression and stemness by directly interacting with Sp1 to transcriptionally activate the Wnt5a/ß-catenin pathway.

Bladder cancer is a common malignancy with a poor prognosis worldwide. Positive cofactor 4 (PC4) is widely reported to promote malignant phenotypes in various tumors. Nonetheless, the biological function and mechanism of PC4 in bladder cancer remain unclear. Here, for the first time, we report that PC4 is elevated in bladder cancer and is associated with patient survival. Moreover, PC4 deficiency obviously inhibited bladder cancer cell proliferation and metastasis by reducing the expression of genes related to cancer stemness (CD44, CD47, KLF4 and c-Myc). Through RNA-seq and experimental verification, we found that activation of the Wnt5a/ß-catenin pathway is involved in the malignant function of PC4. Mechanistically, PC4 directly interacts with Sp1 to promote Wnt5a transcription. Thus, our study furthers our understanding of the role of PC4 in cancer stemness regulation and provides a promising strategy for bladder cancer therapy.

Periodic changes of cyclin D1 mRNA stability are regulated by PC4 modifications in the cell cycle.

The cell cycle is a highly regulated process in which proteins involved in cell cycle progression exhibit periodic expression patterns, controlled by specific mechanisms such as transcription, translation, and degradation. However, the precise mechanisms underlying the oscillations of mRNA levels in cell cycle regulators are not fully understood. In this study, we observed that the stability of cyclin D1 (CCND1) mRNA fluctuates during the cell cycle, with increased stability during interphase and decreased stability during the M phase. Additionally, we identified a key RNA binding protein, positive coactivator 4 (PC4), which plays a crucial role in stabilizing CCND1 mRNA and regulating its periodic expression. Moreover, the binding affinity of PC4 to CCND1 mRNA is modulated by two cell cycle-specific posttranslational modifications: ubiquitination of K68 enhances binding and stabilizes the CCND1 transcript during interphase, while phosphorylation of S17 inhibits binding during the M phase, leading to degradation of CCND1 mRNA. Remarkably, PC4 promotes the transition from G1 to S phase in the cell cycle, and depletion of PC4 enhances the efficacy of CDK4/6 inhibitors in hepatocellular carcinoma, suggesting that PC4 could serve as a potential therapeutic target. These findings provide valuable insights into the intricate regulation of cell cycle dynamics.

IR-780 Dye-based Targeting of Cancer-associated Fibroblasts Improves Cancer Immunotherapy by Increasing Intra-tumoral T Lymphocytes Infiltration.

BACKGROUND: Immune-checkpoint inhibitors (ICIs) against programmed death (PD)-1/PD-L1 pathway immunotherapy have been demonstrated to be effective in only a subset of patients with cancer, while the rest may exhibit low response or may develop drug resistance after initially responding. Previous studies have indicated that extensive collagen-rich stroma secreted by cancer-associated fibroblasts (CAFs) within the tumor microenvironment is one of the key obstructions of the immunotherapy for some tumors by decreasing the infiltrating cytotoxic T cells. However, there is still a lack of effective therapeutic strategies to control the extracellular matrix by targeting CAFs. METHODS: The enhanced uptake of IR-780 by CAFs was assessed by using in vivo or ex vivo nearinfrared fluorescence imaging, confocal NIR fluorescent imaging, and CAFs isolation testing. The fibrotic phenotype down-regulation effects and in vitro CAFs killing effect of IR-780 were tested by qPCR, western blot, and flow cytometry. The in vivo therapeutic enhancement of anti-PD-L1 by IR-780 was evaluated on EMT6 and MC38 subcutaneous xenograft mice models. RESULTS: IR-780 has been demonstrated to be preferentially taken up by CAFs and accumulate in the mitochondria. Further results identified low-dose IR-780 to downregulate the fibrotic phenotype, while high-dose IR-780 could directly kill both CAFs and EMT6 cells in vitro. Moreover, IR-780 significantly inhibited extracellular matrix (ECM) protein deposition in the peri-tumoral stroma on subcutaneous EMT6 and MC38 xenografts, which increased the proportion of tumor-infiltrating lymphocytes (TILs) in the deep tumor and further promoted anti-PD-L1 therapeutic efficacy. CONCLUSION: This work provides a unique strategy for the inhibition of ECM protein deposition in the tumor microenvironment by targeted regulating of CAFs, which destroys the T cell barrier and further promotes tumor response to PD-L1 monoclonal antibody. IR-780 has been proposed as a potential therapeutic small-molecule adjuvant to promote the effect of immunotherapy.

Nocardia rubra cell-wall skeleton mitigates whole abdominal irradiation-induced intestinal injury via regulating macrophage function.

Background: Ionizing radiation (IR)-induced intestinal injury is a major side effect and dose-limiting toxicity in patients receiving radiotherapy. There is an urgent need to identify an effective and safe radioprotectant to reduce radiation-induced intestinal injury. Immunoregulation is considered an effective strategy against IR-induced injury. The purpose of this article was to investigate the protective effect of Nocardia rubra cell wall skeleton (Nr-CWS), an immunomodulator, on radiation-induced intestinal damage and to explore its potential mechanism. Methods: C57BL/6 J male mice exposed to 12 Gy whole abdominal irradiation (WAI) were examined for survival rate, morphology and function of the intestine and spleen, as well as the gut microbiota, to comprehensively evaluate the therapeutic effects of Nr-CWS on radiation-induced intestinal and splenetic injury. To further elucidate the underlying mechanisms of Nr-CWS-mediated intestinal protection, macrophages were depleted by clodronate liposomes to determine whether Nr-CWS-induced radioprotection is macrophage dependent, and the function of peritoneal macrophages stimulated by Nr-CWS was detected in vitro. Results: Our data showed that Nr-CWS promoted the recovery of intestinal barrier function, enhanced leucine-rich repeat-containing G protein-coupled receptor 5+ intestinal stem cell survival and the regeneration of intestinal epithelial cells, maintained intestinal flora homeostasis, protected spleen morphology and function, and improved the outcome of mice exposed to 12 Gy WAI. Mechanistic studies indicated that Nr-CWS recruited macrophages to reduce WAI-induced intestinal damage. Moreover, macrophage depletion by clodronate liposomes blocked Nr-CWS-induced radioprotection. In vitro, we found that Nr-CWS activated the nuclear factor kappa-B signaling pathway and promoted the phagocytosis and migration ability of peritoneal macrophages. Conclusions: Our study suggests the therapeutic effect of Nr-CWS on radiation-induced intestinal injury, and provides possible therapeutic strategy and potential preventive and therapeutic drugs to alleviate it.