Adipose-derived stromal cells in regulation of hematopoiesis.

Over the past decade, mesenchymal stromal cells (MSCs) found in the bone marrow microenvironment have been considered to be important candidates in cellular therapy. However, the application of MSCs in clinical settings is limited by the difficulty and low efficiency associated with the separation of MSCs from the bone marrow. Therefore, distinct sources of MSCs have been extensively explored. Adipose-derived stromal cells (ASCs), a cell line similar to MSCs, have been identified as a promising source. ASCs have become increasingly popular in many fields, as they can be conveniently extracted from fat tissue. This review focuses on the properties of ASCs in hematopoietic regulation and the underlying mechanisms, as well as the current applications and future perspectives in ASC-based therapy.

Platelets directly regulate DNA damage and division of Staphylococcus aureus.

Platelets (PLTs) are classically used in the clinical setting to maintain hemostasis. Recent evidence supports important roles for PLTs in host inflammatory and immune responses, and PLT-rich plasma has been demonstrated to inhibit the growth of bacteria in vitro and in vivo; however, few studies have examined whether PLTs can inhibit bacterial growth directly, and related mechanisms have not been elucidated further. Accordingly, in this study, we evaluated the effects of PLTs on bacterial growth. We washed and purified PLTs from peripheral blood, then confirmed that PLTs significantly inhibited the growth of Staphylococcus aureus when cocultured in vitro. Moreover, PLTs damaged DNA and blocked cell division in S. aureus. During coculture, PLT-derived TGF-ß1 was dramatically down-regulated compared with that in PLT culture alone, and the addition of TGF-ß1 to the coculture system promoted the inhibition of PLTs on S. aureus. Analysis of a murine S. aureus infection model demonstrated that the depletion of PLTs exacerbated the severity of infection, whereas the transfusion of PLTs alleviated this infection. Our observations demonstrate that PLTs could directly inhibit the growth of S. aureus by damaging DNA and blockage cell division, and that PLT-derived TGF-ß1 may play an important role in this machinery.-Xu, J., Yi, J., Zhang, H., Feng, F., Gu, S., Weng, L., Zhang, J., Chen, Y., An, N., Liu, Z., An, Q., Yin, W., Hu, X. Platelets directly regulate DNA damage and division of Staphylococcus aureus.

ROS signaling under metabolic stress: cross-talk between AMPK and AKT pathway.

Cancer cells are frequently confronted with metabolic stress in tumor microenvironments due to their rapid growth and limited nutrient supply. Metabolic stress induces cell death through ROS-induced apoptosis. However, cancer cells can adapt to it by altering the metabolic pathways. AMPK and AKT are two primary effectors in response to metabolic stress: AMPK acts as an energy-sensing factor which rewires metabolism and maintains redox balance. AKT broadly promotes energy production in the nutrient abundance milieu, but the role of AKT under metabolic stress is in dispute. Recent studies show that AMPK and AKT display antagonistic roles under metabolic stress. Metabolic stress-induced ROS signaling lies in the hub between metabolic reprogramming and redox homeostasis. Here, we highlight the cross-talk between AMPK and AKT and their regulation on ROS production and elimination, which summarizes the mechanism of cancer cell adaptability under ROS stress and suggests potential options for cancer therapeutics.

Sca-1(+) mesenchymal stromal cells inhibit splenic marginal zone B lymphocytes commitment through Caspase-3.

Mesenchymal stromal cells (MSCs) have been characterized as an important component of hematopoietic niche, which are capable of modulating the immune system through interaction with a wide range of immune cells. Marginal zone B cells, one main type of mature B lymphocytes, play a central role in eliciting antibody response against pathogens. However, how MSCs and its subpopulations regulate marginal zone B cells commitment is unknown yet. In this study, we assessed the contribution of Sca-1(+) MSCs on marginal zone B cells commitment. Our results showed that Sca-1(+) MSCs inhibit the commitment of marginal zone B lymphocytes. The inhibition was exerted through lowered Caspase-3 expression. Furthermore, we found marginal zone B lymphocytes in spleen of Caspase-3 knockout mice decreased and Caspase-3 knockout Sca-1(+) MSCs accounted for the MZB lymphocytes decrease. In conclusion, our investigation provided clues about Sca-1(+) MSCs regulation on the commitment of marginal zone B cells through Caspase-3 gene.

Supernatant of platelet-Klebsiella pneumoniae coculture induces apoptosis-like death in Klebsiella pneumoniae.

Multidrug-resistant Klebsiella pneumoniae strains, especially carbapenem-resistant K. pneumoniae, have become a rapidly emerging crisis worldwide, greatly limiting current therapeutic options and posing new challenges to infection management. Therefore, it is imperative to develop novel and effective biological agents for the treatment of multidrug-resistant K. pneumoniae infections. Platelets play an important role in the development of inflammation and immune responses. The main component responsible for platelet antibacterial activity lies in the supernatant stimulated by gram-positive bacteria. However, little research has been conducted on the interaction of gram-negative bacteria with platelets. Therefore, we aimed to explore the bacteriostatic effect of the supernatant derived from platelet-K. pneumoniae coculture and the mechanism underlying this effect to further assess the potential of platelet-bacterial coculture supernatant. We conducted this study on the gram-negative bacteria K. pneumoniae and CRKP and detected turbidity changes in K. pneumoniae and CRKP cultures when grown with platelet-K. pneumoniae coculture supernatant added to the culture medium. We found that platelet-K. pneumoniae coculture supernatant significantly inhibited the growth of K. pneumoniae and CRKP in vitro. Furthermore, transfusion of platelet-K. pneumoniae coculture supernatant alleviated the symptoms of K. pneumoniae and CRKP infection in a murine model. Additionally, we observed apoptosis-like changes, such as phosphatidylserine exposure, chromosome condensation, DNA fragmentation, and overproduction of reactive oxygen species in K. pneumoniae following treatment with the supernatant. Our study demonstrates that the platelet-K. pneumoniae coculture supernatant can inhibit K. pneumoniae growth by inducing an apoptosis-like death, which is important for the antibacterial strategies development in the future.IMPORTANCEWith the widespread use of antibiotics, bacterial resistance is increasing, and a variety of multi-drug resistant Gram-negative bacteria have emerged, which brings great challenges to the treatment of infections caused by Gram-negative bacteria. Therefore, finding new strategies to inhibit Gram-negative bacteria and even multi-drug- resistant Gram-negative bacteria is crucial for treating infections caused by Gram-negative bacteria, improving the abuse of antibiotics, and maintaining the balance between bacteria and antibiotics. K. pneumoniae is a common clinical pathogen, and drug-resistant CRKP is increasingly difficult to cure, which brings great clinical challenges. In this study, we found that the platelet-K. pneumoniae coculture supernatant can inhibit K. pneumoniae growth by inducing an apoptosis-like death. This finding has inspired the development of future antimicrobial strategies, which are expected to improve the clinical treatment of Gram-negative bacteria and control the development of multidrug-resistant strains.

Mac1+/Gr1+ cells contribute to transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is a serious complication associated with blood transfusion and can cause transfusion associated fatalities. Both antibody dependent and non-dependent mechanisms are involved in TRALI, as proposed over the past years. Nonetheless, many details of the immune cells involved in TRALI, particularly the Mac1(+)/Gr1(+) cells from donors, are not fully understood yet. Here we used an in vitro transwell system and a mouse model to study the role of donor leukocytes, present in the donor material, in the occurrence of TRALI reactions. We found that there is a number of immature myeloid cells with Mac1(+)/Gr1(+) phenotype present in the red blood cell (RBC) products, when prepared by regular methods. We found that murine Mac1(+)/Gr1(+) cells from stored RBC products display an elevated MHC I and CD40 expression, as well as an enhanced tumor necrosis factor alpha(TNF-α), interlukin-6(IL-6) and macrophage inflammatory protein 2 (MIP-2) secretion. When tested in a transwell endothelial migration assay, Mac1(+)/Gr1(+) cells showed a significant capability to cross the endothelial barrier. In vivo investigation demonstrated that compared to the purified RBC transfusion, more murine Mac1(+)/Gr1(+) cells from the regular method produced RBC sequestered in the lung, which associated to shorter survival. Taken together, these data suggest that donor derived Mac1(+)/Gr1(+) cells can play a significant role in TRALI reactions, and that reduction of Mac1(+)/Gr1(+) cell number from RBC products is necessary to control the severity of TRALI reactions in clinic.

Association of PIK3CA mutation with outcomes in HER2-positive breast cancer treated with anti-HER2 therapy: A meta-analysis and bioinformatic analysis of TCGA­BRCA data.

BACKGROUND: This study aimed to comprehensively explore the clinical significance of PIK3CA mutation in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with anti-HER2 therapy. METHODS: We systematically searched PubMed, Embase, and the Cochrane databases for eligible studies assessing the association between PIK3CA mutation and outcomes in patients with HER2-positive breast cancer receiving anti-HER2 therapy. The main outcomes included: (1) pathological complete response (pCR) or disease-free survival (DFS) for the neoadjuvant setting; (2) DFS or invasive DFS for the adjuvant setting; (3) objective response rate (ORR), progression-free survival (PFS), time-to-progression (TTP), or overall survival (OS) for the metastatic setting. The mutational landscape of HER2-positive breast cancer according to PIK3CA mutation status was examined based on TCGA breast cancer dataset. RESULTS: Totally, 43 eligible studies, covering 11,099 patients with available data on PIK3CA mutation status, were identified. In the neoadjuvant setting, PIK3CA mutation was significantly associated with a lower pCR rate (OR=0.23, 95% CI 0.19-0.27, p<0.001). This association remained significant irrespective of the type of anti-HER2 therapy (single-agent or dual-agent) and hormone receptor status. There were no significant differences in DFS between PIK3CA mutated and wild-type patients in either the neoadjuvant or adjuvant settings. In the metastatic setting, PIK3CA mutation predicted worse ORR (OR=0.26, 95%CI 0.17-0.40, p<0.001), PFS (HR=1.28, 95%CI 1.03-1.59, p = 0.024) and TTP (HR=2.27, 95%CI 1.54-3.34, p<0.001). However, no significant association was observed between PIK3CA mutation status and OS. Distinct mutational landscapes were observed in HER2-positive breast cancer between individuals with PIK3CA mutations and those with wild-type PIK3CA. CONCLUSIONS: PIK3CA mutation was significantly associated with a lower pCR rate in HER2-positive breast cancer treated with neoadjuvant anti-HER2 therapy. In the metastatic setting, PIK3CA mutation was predictive of worse ORR, PFS and TTP. These results suggest the potential for developing PI3K inhibitors as a therapeutic option for these patients.

Platelet-Derived Mitochondria Attenuate 5-FU-Induced Injury to Bone-Associated Mesenchymal Stem Cells.

Background: Myelosuppression is a common condition during chemotherapy. Bone-associated mesenchymal stem cells (BA-MSCs) play an essential role in the composition of the hematopoietic microenvironment and support hematopoietic activity. However, chemotherapy-induced damage to BA-MSCs is rarely studied. Recent studies have shown that platelets promote the wound-healing capability of MSCs by mitochondrial transfer. Therefore, this study is aimed at investigating the chemotherapy-induced damage to BA-MSCs and the therapeutic effect of platelet-derived mitochondria. Material/Methods. We established in vivo and in vitro BA-MSC chemotherapy injury models using the chemotherapy agent 5-fluorouracil (5-FU). Changes in the mitochondrial dynamics were detected by transmission electron microscopy, and the expression of mitochondrial fusion and fission genes was analyzed by qRT-PCR. In addition, mitochondrial functions were also explored by flow cytometry and luminometer. Platelet-derived mitochondria were incubated with 5-FU-damaged BA-MSCs to repair the injury, and BA-MSC functional changes were examined to assess the therapy efficacy. The mechanism of treatment was explored by studying the expression of mitochondrial fission and fusion genes and hematopoietic regulatory factor genes in BA-MSCs. Results: Stimulation with 5-FU increased the apoptosis and suppressed cell cycle progression of BA-MSCs both in vivo and in vitro. In addition, 5-FU chemotherapy inhibited the hematopoietic regulatory ability and disrupted the mitochondrial dynamics and functions of BA-MSCs. The mitochondrial membrane potential and ATP content of 5-FU-injured BA-MSCs were decreased. Interestingly, when platelet-derived mitochondria were transferred to BA-MSCs, the 5-FU-induced apoptosis was alleviated, and the hematopoietic regulatory ability of 5-FU-injured BA-MSCs was effectively improved by upregulating the expression of mitochondrial fusion genes and hematopoietic regulatory factor genes. Conclusion: BA-MSCs were severely damaged by 5-FU chemotherapy both in vivo and in vitro. Meanwhile, platelet-derived mitochondria could attenuate the 5-FU-induced injury to BA-MSCs, which provides future research directions for exploring the treatment strategies for chemotherapy-injured BA-MSCs and establishes a research basis for related fields.

Analysis between ABO blood group and clinical outcomes in COVID-19 patients and the potential mediating role of ACE2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the most common coronavirus that causes large-scale infections worldwide. Currently, several studies have shown that the ABO blood group is associated with coronavirus disease 2019 (COVID-19) infection and some studies have also suggested that the infection of COVID-19 may be closely related to the interaction between angiotensin-converting enzyme 2 (ACE2) and blood group antigens. However, the relationship between blood type to clinical outcome in critically ill patients and the mechanism of action is still unclear. The current study aimed to examine the correlation between blood type distribution and SARS-CoV-2 infection, progression, and prognosis in patients with COVID-19 and the potential mediating role of ACE2. With 234 patients from 5 medical centers and two established cohorts, 137 for the mild cohort and 97 for the critically ill cohort, we found that the blood type A population was more sensitive to SARS-CoV-2, while the blood type distribution was not relevant to acute respiratory distress syndrome (ARDS), acute kidney injury (AKI), and mortality in COVID-19 patients. Further study showed that the serum ACE2 protein level of healthy people with type A was significantly higher than that of other blood groups, and type O was the lowest. The experimental results of spike protein binding to red blood cells also showed that the binding rate of people with type A was the highest, and that of people with type O was the lowest. Our finding indicated that blood type A may be the biological marker for susceptibility to SARS-CoV-2 infection and may be associated with potential mediating of ACE2, but irrelevant to the clinical outcomes including ARDS, AKI, and death. These findings can provide new ideas for clinical diagnosis, treatment, and prevention of COVID-19.

NLRP3 inflammasome inhibition of OP9 cells enhance therapy for inflammatory bowel disease.

Mesenchymal stem cells (MSCs) are becoming more popular in therapy. Therefore, in-depth studies on mesenchymal stem cells in therapy are urgently needed. However, the difficulty in culturing and propagating MSCs in vitro complicates potential studies on MSCs in a murine model. OP9 cells are a stromal cell line from mouse bone marrow, which have similar characteristics and functions to MSCs and can maintain their original characteristics. Because of these properties, OP9 cells have become a suitable substitute for research on MSCs. Previously, we have found that MSCs can cure inflammatory bowel disease in mice. In this study, we aimed to investigate whether OP9 cells can functionally regulate and alleviate inflammatory diseases. We evaluated the therapeutic effect of OP9 cells in the mouse model of inflammatory bowel disease and found OP9 cells were able to ameliorate inflammatory bowel disease. We explored the existence of NLRP3 inflammasome in OP9 cells, and showed better therapeutic effects when the NLRP3 inflammasome was suppressed. Thus, OP9 cell line is similar to MSCs in characteristic and function, and is an ideal substitute for MSCs research. The preliminary exploration of the inflammasome system in OP9 cells lays a theoretical and methodological foundation for further study of MSCs.

A reference interval study of ferritin and transferrin levels in donors from two blood centers.

Blood donors not only save the lives of patients but also play an important role in the development of medical and health services. Therefore, it is particularly important to pay attention to the blood health of blood donors who are at a high risk of iron deficiency. Detection of serum ferritin and transferrin is an important basis for the diagnosis of iron deficiency anemia. However, to the best of our knowledge, the levels of serum ferritin and transferrin, and the influencing factors, such as age and type of donation, in blood donors have not been clarified. In the present study, the serum ferritin and transferrin levels of donors from two blood centers were investigated. Demographic data were collected from the donors, and their serum ferritin and transferrin levels were tested. A total of 1,817 donors were enrolled and were eligible for evaluation. Reference intervals (RIs) for ferritin and transferrin were obtained from blood donors, and it was revealed that the ferritin and transferrin levels of blood donors were associated with age. Furthermore, serum transferrin levels were associated with the type of donation; the serum transferrin RI level was significantly higher in platelet-only donors compared with in whole blood donors. It was also demonstrated that ferritin levels were negatively associated with transferrin levels. The present study identified RIs for ferritin and transferrin levels in blood donors, and indicated that age and type of donation were important factors affecting ferritin and transferrin levels in blood donors. These findings may prove useful for blood donation recruitment and screening strategies in China, and could promote the health of blood donors.

A novel coumarin derivative DBH2 inhibits proliferation and induces apoptosis of chronic myeloid leukemia cells.

With the development of tyrosine kinase inhibitor (TKI) resistance, finding the novel effective chemotherapeutic agent is of seminal importance for chronic myelogenous leukemia (CML) treatment. This study aims to find the effective anti-leukemic candidates and investigate the possible underlying mechanism. We synthesized the novel coumarin derivatives and evaluated their anti-leukemic activity. Cell viability assay revealed that compound DBH2 exhibited the potent inhibitory activity on the proliferation of CML K562 cells and TKI resistant K562 cells. Morphological observation and flow cytometry confirmed that DBH2 could selectively induce cell apoptosis and cell cycle arrest at G2/M phase of the K562 cells, which was further confirmed on the bone marrow cells from CML transgenic model mice and CD34+ bone marrow leukemic cells from CML patients. Treatments of DBH2 in combination with imatinib could prolong the survival rate of SCL-tTA-BCR/ABL transgenic model mice significantly. Quantitative RT-PCR revealed that DBH2 inhibited the expression of STAT3 and STAT5 in K562 cells, and caspase-3 knockout alleviated the DBH2 induced apoptosis. Furthermore, DBH2 could induce the expression of PARP1 and ROCK1 in K562 cells, which may play the important role in caspase-dependent apoptosis. Our results concluded that coumarin derivative DBH2 serves as a promising candidate for the CML treatment, especially in the combination with imatinib for the TKI resistant CML, and STAT/caspase-3 pathway was involved in the molecular mechanism of anti-leukemic activity of DBH2.

Glutamine metabolic microenvironment drives M2 macrophage polarization to mediate trastuzumab resistance in HER2-positive gastric cancer.

BACKGROUND: Trastuzumab is a first-line targeted therapy for human epidermal growth factor receptor-2 (HER2)-positive gastric cancer. However, the inevitable occurrence of acquired trastuzumab resistance limits the drug benefit, and there is currently no effective reversal measure. Existing researches on the mechanism of trastuzumab resistance mainly focused on tumor cells themselves, while the understanding of the mechanisms of environment-mediated drug resistance is relatively lacking. This study aimed to further explore the mechanisms of trastuzumab resistance to identify strategies to promote survival in these patients. METHODS: Trastuzumab-sensitive and trastuzumab-resistant HER2-positive tumor tissues and cells were collected for transcriptome sequencing. Bioinformatics were used to analyze cell subtypes, metabolic pathways, and molecular signaling pathways. Changes in microenvironmental indicators (such as macrophage, angiogenesis, and metabolism) were verified by immunofluorescence (IF) and immunohistochemical (IHC) analyses. Finally, a multi-scale agent-based model (ABM) was constructed. The effects of combination treatment were further validated in nude mice to verify these effects predicted by the ABM. RESULTS: Based on transcriptome sequencing, molecular biology, and in vivo experiments, we found that the level of glutamine metabolism in trastuzumab-resistant HER2-positive cells was increased, and glutaminase 1 (GLS1) was significantly overexpressed. Meanwhile, tumor-derived GLS1 microvesicles drove M2 macrophage polarization. Furthermore, angiogenesis promoted trastuzumab resistance. IHC showed high glutamine metabolism, M2 macrophage polarization, and angiogenesis in trastuzumab-resistant HER2-positive tumor tissues from patients and nude mice. Mechanistically, the cell division cycle 42 (CDC42) promoted GLS1 expression in tumor cells by activating nuclear factor kappa-B (NF-κB) p65 and drove GLS1 microvesicle secretion through IQ motif-containing GTPase-activating protein 1 (IQGAP1). Based on the ABM and in vivo experiments, we confirmed that the combination of anti-glutamine metabolism, anti-angiogenesis, and pro-M1 polarization therapy had the best effect in reversing trastuzumab resistance in HER2-positive gastric cancer. CONCLUSIONS: This study revealed that tumor cells secrete GLS1 microvesicles via CDC42 to promote glutamine metabolism, M2 macrophage polarization, and pro-angiogenic function of macrophages, leading to acquired trastuzumab resistance in HER2-positive gastric cancer. A combination of anti-glutamine metabolism, anti-angiogenesis, and pro-M1 polarization therapy may provide a new insight into reversing trastuzumab resistance.

Cognitive impairment in psychiatric diseases: Biomarkers of diagnosis, treatment, and prevention.

Psychiatric diseases, such as schizophrenia, bipolar disorder, autism spectrum disorder, and major depressive disorder, place a huge health burden on society. Cognitive impairment is one of the core characteristics of psychiatric disorders and a vital determinant of social function and disease recurrence in patients. This review thus aims to explore the underlying molecular mechanisms of cognitive impairment in major psychiatric disorders and identify valuable biomarkers for diagnosis, treatment and prevention of patients.

[High expression of P-selectin (CD62P) after platelet activation in vitro inhibits bacterial proliferation and induces apoptosis-like changes].

Objective To compare the expression level of P-selectin (CD62P) on platelets surface under the stimulation of Staphylococcus aureus (SA) and Escherichia coli (E.coli), explore the inhibitory effects of platelets on the their proliferation, and further investigate the molecular mechanism by which platelets inhibit the proliferation of bacteria. Methods 106 CFU/mL SA and E.coli were co-cultured with 2×1011/L purified platelets, and the A600 values of the two groups were detected; The CD62P of platelets was detected by flow cytometry after platelets co-cultured with SA and E.coli for 2 hours and 4 hours. The platelet factor 4 (PF4) released by platelets was detected by ELISA; After co-cultured with SA and E.coli for 12 hours, the proliferation, phosphatidylserine (PS) eversion and cell membrane potential of SA and E.coli were analyzed by flow cytometry. Results After platelets co-cultured with SA and E.coli for 6 hours, the turbidity of SA decreased significantly and the turbidity of E.coli showed a slight decrease. Compared with the control group, the counts of bacterial plates decreased after two kinds of bacteria co-cultured with platelets. After co-cultured with SA and E.coli for 2 hours and 4 hours, the CD62P levels of platelets increased. In particular, the CD62P level of platelets co-cultured with SA was significantly higher than that of platelets co-cultured with E.coli. The release of intracellular protein PF4 of platelet increased significantly after bacteria stimulation. The proliferation rate of SA and E.coli decreased after co-cultured with platelets, and SA and E.coli exhibited PS eversion and depolarization of cell membrane potential. Conclusion High expression of CD62P inhibits the proliferation and induces apoptotic changes of SA and E.coli after platelets activation in vitro, and the inhibitory effect of platelets on SA was better than that of E.coli.

Disrupting Circadian Rhythm via the PER1-HK2 Axis Reverses Trastuzumab Resistance in Gastric Cancer.

Trastuzumab is the only approved targeted drug for first-line treatment of HER2-positive advanced gastric cancer, but the high rate of primary resistance and rapid emergence of secondary resistance limit its clinical benefits. We found that trastuzumab-resistant (TR) gastric cancer cells exhibited high glycolytic activity, which was controlled by hexokinase 2 (HK2)-dependent glycolysis with a circadian pattern [higher at zeitgeber time (ZT) 6, lower at ZT18]. Mechanistically, HK2 circadian oscillation was regulated by a transcriptional complex composed of PPARγ and the core clock gene PER1. In vivo and in vitro experiments demonstrated that silencing PER1 disrupted the circadian rhythm of PER1-HK2 and reversed trastuzumab resistance. Moreover, metformin, which inhibits glycolysis and PER1, combined with trastuzumab at ZT6, significantly improved trastuzumab efficacy in gastric cancer. Collectively, these data introduce the circadian clock into trastuzumab therapy and propose a potentially effective chronotherapy strategy to reverse trastuzumab resistance in gastric cancer. SIGNIFICANCE: In trastuzumab-resistant HER2-positive gastric cancer, glycolysis fluctuates with a circadian oscillation regulated by the BMAL1-CLOCK-PER1-HK2 axis, which can be disrupted with a metformin-based chronotherapy to overcome trastuzumab resistance.

Remodeling Chondroitin-6-Sulfate-Mediated Immune Exclusion Enhances Anti-PD-1 Response in Colorectal Cancer with Microsatellite Stability.

Metastatic microsatellite-stable (MSS) colorectal cancer rarely responds to immune checkpoint inhibitors (ICI). Metabolism heterogeneity in the tumor microenvironment (TME) presents obstacles to antitumor immune response. Combining transcriptome (The Cancer Genome Atlas MSS colorectal cancer, n = 383) and digital pathology (n = 96) analysis, we demonstrated a stroma metabolism-immune excluded subtype with poor prognosis in MSS colorectal cancer, which could be attributed to interaction between chondroitin-6-sulfate (C-6-S) metabolites and M2 macrophages, forming the "exclusion barrier" in the invasive margin. Furthermore, C-6-S derived from cancer-associated fibroblasts promoted co-nuclear translocation of pSTAT3 and GLI1, activating the JAK/STAT3 and Hedgehog pathways. In vivo experiments with C-6-S-targeted strategies decreased M2 macrophages and reprogrammed the immunosuppressive TME, leading to enhanced response to anti-PD-1 in MSS colorectal cancer. Therefore, C-6-S-induced immune exclusion represents an "immunometabolic checkpoint" that can be exploited for the application of combination strategies in MSS colorectal cancer ICI treatment.

MET transcriptional regulator/serine peptidase inhibitor kunitz type 1 panel operating through HGF/c-MET axis as a prognostic signature in pan-cancer.

Dysregulations in transcription factors (TFs) and their genetic products play important roles in tumorigenesis, tumor progression and metastasis. However, prognostic value of the transcriptional regulatory networks in different cancers has not been investigated in depth. The purpose of our study was to identify and validate a potential predictive signature that combines TFs and their regulatory products in eight solid tumors. We used bioinformatics analysis to identify MET Transcriptional Regulator (MACC1) and Serine Peptidase Inhibitor Kunitz Type 1 (SPINT1) as candidate TFs with the respective downstream regulatory proteins for patient prognosis in pan-cancer. Subsequent molecular analysis of clinical gastric cancer tissue samples further verified the negative correlation between MACC1 and SPINT1. Further, we showed that mechanistically, MACC1/SPINT1 mediated the pro-HGF proteolysis and c-Met phosphorylation in HGF/c-MET signaling pathway. Kaplan-Meier plots and receiver operating characteristics analysis revealed that the two-gene signature combining MACC1 with SPINT1 was effective in predicting survival in all eight cancer cohorts tested. In conclusion, our study clarified the regulatory relationship between MACC1 and SPINT1 in the context of the HGF/c-MET signaling pathway and determined MACC1/SPINT1 panel as a valuable signature for the prediction of prognosis in patients for multiple solid cancer types.

Caspase-3/NLRP3 signaling in the mesenchymal stromal niche regulates myeloid-biased hematopoiesis.

BACKGROUND: The fate of hematopoietic stem cells (HSCs) is determined by a complex regulatory network that includes both intrinsic and extrinsic signals. In the past decades, many intrinsic key molecules of HSCs have been shown to control hematopoiesis homeostasis. Non-hematopoietic niche cells also contribute to the self-renewal, quiescence, and differentiation of HSCs. Mesenchymal stromal cells (MSCs) have been identified as important components of the niche. However, the regulatory role of MSCs in hematopoiesis has not been fully understood. METHODS: Caspase-3 and NLRP3 gene knockout mice were generated respectively, and hematopoietic development was evaluated in the peripheral circulation and bone marrow by flow cytometry, colony formation assay, and bone marrow transplantation. Bone-associated MSCs (BA-MSCs) were then isolated from gene knockout mice, and the effect of Caspase-3/NLRP3 deficient BA-MSCs on hematopoiesis regulation was explored in vivo and ex vivo. RESULTS: We report that Caspase-3 deficient mice exhibit increased myelopoiesis and an aberrant HSC pool. Ablation of Caspase-3 in BA-MSCs regulates myeloid lineage expansion by altering the expression of hematopoietic retention cytokines, including SCF and CXCL12. Interestingly, NLRP3 gene knockout mice share phenotypic similarities with Caspase-3 deficient mice. Additionally, we found that NLRP3 may play a role in myeloid development by affecting the cell cycle and apoptosis of hematopoietic progenitors. CONCLUSIONS: Our data demonstrate that the Caspase-3/NLRP3 signaling functions as an important regulator in physiological hematopoiesis, which provides new insights regarding niche signals that influence hematopoiesis regulation in the bone marrow.

NLRP3 inflammasome of renal tubular epithelial cells induces kidney injury in acute hemolytic transfusion reactions.

BACKGROUND: Blood transfusion, a common basic supporting therapy, can lead to acute hemolytic transfusion reaction (AHTR). AHTR poses a great risk to patients through kidney function damage in a short time. Previous reports found that heme from destroyed red blood cells impaired kidney function, and NLR family pyrin domain containing 3 (NLRP3) inflammasome was augmented in case of kidney injury. However, the detailed mechanism regarding whether NLRP3 inflammasome is involved in kidney function injury in AHTR is not fully understood yet. METHODS: Hemolysis models were established by vein injection with human blood plasma or mouse heme from destroyed red blood cells. The injured renal tubular epithelial cells (RTECs) were evaluated by tubular damage markers staining in hemolysis models and in primary RTECs in vitro. The activation of NLRP3 inflammasome in RTECs by hemes was investigated by Western blot, ELISA, scanning electron microscopy, immunofluorescent staining, flow cytometry, and hemolysis models. NLRP3 gene knockout mice were employed to confirm these observations in vitro and in vivo. The binding between a novel inhibitor (66PR) and NLRP3 was affirmed by molecule docking and co-immunoprecipitation. The rescue of 66PR on kidney function impairment was explored in murine hemolysis models. RESULTS: We found that heme could activate NLRP3 inflammasome in RTECs to induce kidney function injury. NLRP3 gene knockout could prevent the damage of RTECs caused by hemes and recover kidney function in AHTR. Moreover, NLRP3 inflammasome chemical inhibitor, 66PR, could bind to NLRP3 protein and inhibit inflammasome activation in RTECs, which consequently relieved the injury of RTECs caused by hemes, and alleviated kidney function damage in the AHTR model. CONCLUSIONS: Hemes could activate NLRP3 inflammasome in RTECs, and a novel NLRP3 inflammasome inhibitor named 66PR relieved kidney function damage in AHTR. Our findings provided a new possible strategy to treat kidney function failure in AHTR.