Bone marrow adipocytes is a new player in supporting myeloma cells proliferation and survival in myeloma microenvironment.

Multiple myeloma (MM) is a lethal B cell neoplasm characterized by clonal expansion of malignant plasma cells in the bone marrow and remains incurable due to disease relapse and drug resistance. Bone marrow adipocytes (BMAs) are emerging as playing active functions that can support myeloma cell growth and survival. The aim of this study is to investigate myeloma-mesenchymal stem cells (MSCs) interaction and the impact of such interactions on the pathogenesis of MM using in vitro co-culture assay. Here we provide evidence that MM cell up-regulated MSCs to express PPAR-γ and pushes MSCs differentiation toward adipocytes at the expense of osteoblasts in co-culture manner. The increased BMAs can effectively enhance MM cell to proliferation, migration, and chemoresistance via cell-cell contact and/or cytokines release regulated by PPAR-γ signal pathway. This effect was partially reversed in medium containing PPAR-γ antagonist G3335 and indicated that G3335 distorts the maturation of MSC-derived adipocytes and cytokines release by adipocytes through inhibition of PPAR-γ, a key transcriptional factor for the activation of adipogenesis, or cell to cell contact, or both. In meantime, we observed higher expression of adipocyte differentiation associated genes DLK1, DGAT1, FABP4, and FASN both in MSCs and MSC derived adipocytes, but the osteoblast differentiation-associated gene ALP was down regulated in MSCs. These finding mean that direct consequence of MM/MSC interaction that play a role in MM pathogenesis. Consistent with those in vitro results, our primary clinical observation also showed that bone marrow samples from MM patients had significantly higher bone adiposity in comparison with controls and the number of adipocytes decreased in those who were response to anti-MM therapy. Our finding suggested that BMAs may have an important contribution to MM progression, particularly in drugs resistant of MM cells, and plays an important contribution in MM bone disease and treatment failure, but more clinical studies are needed to confirm its role.

LAIR1 drives glioma progression by nuclear focal adhesion kinase dependent expressions of cyclin D1 and immunosuppressive chemokines/cytokines.

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR1), an immune receptor containing immunoreceptor tyrosine-based inhibiory motifs (ITIMs), has emerged as an attractive target for cancer therapy. However, the intrinsic function of LAIR1 in gliomas remains unclear. In this study, the poor prognosis of glioma patients and the malignant proliferation of glioma cells in vitro and in vivo were found to be closely correlated with LAIR1. LAIR1 facilitates focal adhesion kinase (FAK) nuclear localization, resulting in increased transcription of cyclin D1 and chemokines/cytokines (CCL5, TGFß2, and IL33). LAIR1 specifically supports in the immunosuppressive glioma microenvironment via CCL5-mediated microglia/macrophage polarization. SHP2Q510E (PTP domain mutant) or FAKNLM (non-nuclear localizing mutant) significantly reversed the LAIR1-induced growth enhancement in glioma cells. In addition, LAIR1Y251/281F (ITIMs mutant) and SHP2Q510E mutants significantly reduced FAK nuclear localization, as well as CCL5 and cyclin D1 expression. Further experiments revealed that the ITIMs of LAIR1 recruited SH2-containing phosphatase 2 (SHP2), which then interacted with FAK and induced FAK nuclear localization. This study uncovered a critical role for intrinsic LAIR1 in facilitating glioma malignant progression and demonstrated a requirement for LAIR1 and SHP2 to enhance FAK nuclear localization.

[Bone Marrow Adipocytes Promote the Survival of Multiple Myeloma Cells and Up-Regulate Their Chemoresistance].

OBJECTIVE: To investigate the effect of adipocytes in the bone marrow microenvironment of patients with multiple myeloma (MM) on the pathogenesis of MM. METHODS: Bone marrow adipocytes (BMA) in bone marrow smears of health donors (HD) and newly diagnosed MM (ND-MM) patients were evaluated with oil red O staining. The mesenchymal stem cells (MSC) from HD and ND-MM patients were isolated, and in vitro co-culture assay was used to explore the effects of MM cells on the adipogenic differentiation of MSC and the role of BMA in the survival and drug resistance of MM cells. The expression of adipogenic/osteogenic differentiation-related genes PPAR-γ, DLK1, DGAT1, FABP4, FASN and ALP both in MSC and MSC-derived adipocytes was determined with real-time quantitative PCR. The Western blot was employed to detect the expression levels of IL-6, IL-10, SDF-1α, TNF-α and IGF-1 in the supernatant with or without PPAR-γ inhibitor. RESULTS: The results of oil red O staining of bone marrow smears showed that BMA increased significantly in patients of ND-MM compared with the normal control group, and the BMA content was related to the disease status. The content of BMA decreased in the patients with effective chemotherapy. MM cells up-regulated the expression of MSC adipogenic differentiation-related genes PPAR-γ, DLK1, DGAT1, FABP4 and FASN, but the expression of osteogenic differentiation-related gene ALP was significantly down-regulated. This means that the direct consequence of the interaction between MM cells and MSC in the bone marrow microenvironment is to promote the differentiation of MSC into adipocytes at the expense of osteoblasts, and the cytokines detected in supernatant changed. PPAR-γ inhibitor G3335 could partially reverse the release of cytokines by BMA. Those results confirmed that BMA regulated the release of cytokines via PPAR-γ signal, and PPAR-γ inhibitor G3335 could distort PPAR-γ mediated BMA maturation and cytokines release. The increased BMA and related cytokines effectively promoted the proliferation, migration and drug resistance of MM cells. CONCLUSION: The BMA and its associated cytokines are the promoting factors in the survival, proliferation and migration of MM cells. BMA can protect MM cells from drug-induced apoptosis and plays an important role in MM treatment failure and disease progression.

Tuning iron spin states in single-atom nanozymes enables efficient peroxidase mimicking.

The large-scale application of nanozymes remains a significant challenge owing to their unsatisfactory catalytic performances. Featuring a unique electronic structure and coordination environment, single-atom nanozymes provide great opportunities to vividly mimic the specific metal catalytic center of natural enzymes and achieve superior enzyme-like activity. In this study, the spin state engineering of Fe single-atom nanozymes (FeNC) is employed to enhance their peroxidase-like activity. Pd nanoclusters (PdNC) are introduced into FeNC, whose electron-withdrawing properties rearrange the spin electron occupation in Fe(ii) of FeNC-PdNC from low spin to medium spin, facilitating the heterolysis of H2O2 and timely desorption of H2O. The spin-rearranged FeNC-PdNC exhibits greater H2O2 activation activity and rapid reaction kinetics compared to those of FeNC. As a proof of concept, FeNC-PdNC is used in the immunosorbent assay for the colorimetric detection of prostate-specific antigen and achieves an ultralow detection limit of 0.38 pg mL-1. Our spin-state engineering strategy provides a fundamental understanding of the catalytic mechanism of nanozymes and facilitates the design of advanced enzyme mimics.

Single-Atom Iron Enables Strong Low-Triggering-Potential Luminol Cathodic Electrochemiluminescence.

The conventional cathodic electrochemiluminescence (ECL) always requires a more negative potential to trigger strong emission, which inevitably damages the bioactivity of targets and decreases the sensitivity and specificity. In this work, iron single-atom catalysts (Fe-N-C SACs) were employed as an efficient co-reaction accelerator for the first time to achieve the impressively cathodic emission of a luminol-H2O2 ECL system at an ultralow potential. Benefiting from the distinct electronic structure, Fe-N-C SACs exhibit remarkable properties for the activation of H2O2 to produce massive reactive oxygen species (ROS) under a negative scanning potential from 0 to -0.2 V. The ROS can oxidize the luminol anions into luminol anion radicals, avoiding the tedious electrochemical oxidation process of luminol. Then, the in situ-formed luminol anion radicals will directly react with ROS for the strong ECL emission. As a proof of concept, sensitive detection of the carcinoembryonic antigen was realized by glucose oxidase-mediated ECL immunoassay, shedding light on the superiority of SACs to construct efficient cathodic ECL systems with low triggering potential.

Targeting NQO1/GPX4-mediated ferroptosis by plumbagin suppresses in vitro and in vivo glioma growth.

BACKGROUND: Ferroptosis has attracted increasing interest in cancer therapy. Emerging evidences suggest that naturally occurring naphthoquinones exhibit potent anti-glioma effects via various mechanisms. METHODS: The anti-glioma effects of plumbagin were evaluated by in vitro and in vivo experiments. Anti-glioma mechanism of plumbagin was studied by proteomics, flow cytometry, MDA assay, western blot, and RT-PCR. Gene knockdown/overexpression, molecular docking, PharmMappper database, and coimmunoprecipitation were used to study the targets of plumbagin. RESULTS: Plumbagin showed higher blood-brain barrier penetration ability than that of lapachol and shikonin and elicited significant growth inhibitory effects in vitro and in vivo. Ferroptosis was the main mechanism of plumbagin-induced cell death. Mechanistically, plumbagin significantly downregulated the protein and mRNA levels of xCT and decreased GPX4 protein levels. NAD(P)H quinone dehydrogenase 1 (NQO1) was revealed as a plumbagin predictive target using PharmMappper database and molecular docking. Plumbagin enhanced NQO1 activity and decreased xCT expression, resulting in NQO1-dependent cell death. It also induced GPX4 degradation via the lysosome pathway and caused GPX4-dependent cell death. CONCLUSIONS: Plumbagin inhibited in vitro and in vivo glioma growth via targeting NQO1/GPX4-mediated ferroptosis, which might be developed as a novel ferroptosis inducer or anti-glioma candidate.

Iron Single-Atom Catalysts Boost Photoelectrochemical Detection by Integrating Interfacial Oxygen Reduction and Enzyme-Mimicking Activity.

The investigations on the generation, separation, and interfacial-redox-reaction processes of the photoinduced carriers are of paramount importance for realizing efficient photoelectrochemical (PEC) detection. However, the sluggish interfacial reactions of the photogenerated carriers, combined with the need for appropriate photoactive layers for sensing, remain challenges for the construction of advanced PEC platforms. Here, as a proof of concept, well-defined Fe single-atom catalysts (Fe SACs) were integrated on the surface of semiconductors, which amplified the PEC signals via boosting oxygen reduction reaction. Besides, Fe SACs were evidenced with efficient peroxidase-like activity, which depresses the PEC signals through the Fe SACs-mediated enzymatic precipitation reaction. Harnessing the oxygen reduction property and peroxidase-like activity of Fe SACs, a robust PEC sensing platform was successfully constructed for the sensitive detection of acetylcholinesterase activity and organophosphorus pesticides, providing guidelines for the employment of SACs for sensitive PEC analysis.

Iridium Single-Atomic Site Catalysts with Superior Oxygen Reduction Reaction Activity for Sensitive Monitoring of Organophosphorus Pesticides.

Tremendous efforts have been made in developing single-atomic site catalysts (SASCs) for oxygen reduction reaction (ORR), which is regarded as a pivotal cornerstone in electrochemical energy conversion. However, SASCs for ORR have not been explored for electrochemical sensing. Herein, a template-sacrificed strategy is reported for the synthesis of atomically dispersed Ir SASCs, serving as a sensing platform to detect organophosphorus pesticides (OPs) with high sensitivity and selectivity. Owing to abundant Ir single-atom active sites, Ir SASCs show excellent ORR activity and stability in a neutral medium. It is found that the ORR activity of Ir SASCs can be inhibited by thiocholine, which is the hydrolysate of acetylthiocholine. After being integrated with acetylcholinesterase (AChE), the AChE-Ir SASC-based electrochemical sensor is established and shows a superior sensitivity, which shows a wide detection range of 0.5-500 ng mL-1 with a low detection limit of 0.17 ng mL-1 for OPs. This work exhibits a broad application prospect of ORR for sensitive detection of biomolecules.

Modulating Oxygen Reduction Behaviors on Nickel Single-Atom Catalysts to Probe the Electrochemiluminescence Mechanism at the Atomic Level.

Luminol-dissolved O2 electrochemiluminescence (ECL)-sensing platforms have been widely developed for sensitive and reliable detection, while their actual ECL mechanisms are still in controversy due to the involved multiple reactive oxygen species (ROS). Different from the structural complexity of nanomaterials, well-defined single-atom catalysts (SACs) as coreaction accelerators will provide great prospects for investigating the ECL mechanism at the atomic level. Herein, two carbon-supported nickel SACs with the active centers of Ni-N4 (Ni-N4/C) and Ni-N2O2 (Ni-N2O2/C) were synthesized as efficient coreaction accelerators to enhance the ECL signals of a luminol-dissolved O2 system. By modulating the surrounding environment of the center metal atoms, their corresponding oxygen reduction behaviors can be well controlled to selectively produce intermediate ROS, giving a great chance to study the following ECL process. According to the experimental and calculated results, the superoxide radical (O2•-) acts as the main radical for the ECL reaction and the Ni-N4/C catalyst with the four-electron pathway to activate dissolved O2 is preferential to enhance ECL emission.

Panax notoginseng saponins promotes stroke recovery by influencing expression of Nogo-A, NgR and p75NGF, in vitro and in vivo.

The spontaneous recovery of function after injury in the adult central nervous system is limited due to the several proteins, such as Nogo-A that have repulsive or inhibitory effects on growing neuritis. The Chinese herbal medicine extraction Panax notoginseng saponins (PNS) injection has been widely used and effective in repairing the function of impaired nerves, but the mechanism of this herbal medicine is still poorly understood. This project evaluated the effect of Panax notoginseng saponins on neurological functional recovery and on the expression of Nogo-A, NgR and p75 at 7, 14 and 28 d after middle cerebral artery occlusion (MCAO) in rats and also oxygen-glucose deprivation/reperfusion (OGD/R) model on SH-SY5Y cells. We found that the expression of Nogo-A, NgR and p75 of rats receiving MCAO surgery increased on the 7th day, reached a peak on the 14th or 28th day and maintained high levels and Panax notoginseng saponins significantly decreased these expressions. This may be the mechanism of Panax notoginseng saponins that contributes to the recovery of nerve function, which plays an important role in brain protection after cerebral infarction.

Inhibitory kinetics of betaine on beta-N-acetyl-D-glucosaminidase from prawn (Litopenaeus vannamei).

The effects of betaine on prawn beta-N-acetyl-D-glucosaminidase (NAGase) activity for the hydrolysis of p-nitrophenyl-N-acetyl- beta-D-glucosaminide (pNP-NAG) have been studied. The results showed that appropriate concentrations of betaine could lead to reversible inhibition against NAGase, and the IC(50) value was estimated to be 15.00 +/- 0.30 mM. The inhibitory kinetics assay showed that betaine was a mixed type inhibitor with a K(I) value of 9.17 +/- 0.85 mM and a K(IS) value of 45.58 +/- 2.52 mM. The inhibitory model was set, and the microscopic rate constants were determined using the kinetic method of the substrate reaction. The time course of the hydrolysis of pNP-NAG catalyzed by NAGase in the presence of different betaine concentrations showed that at each betaine concentration, the rate decreased with an increase in time until a straight line was approached, indicating that the inhibition of NAGase by betaine is a slow, reversible reaction with fractional residual activity. The fact that k(+0) is much larger than k(+0)(') indicated that the free enzyme molecule is more fragile than the enzyme-substrate complex against betaine. It is suggested that the presence of the substrate offers marked protection of NAGase against inhibition by betaine.

[Gene and haplotype frequencies for the loci HLA-A, B and DRB1 in 11755 north Chinese Han bone marrow registry donors].

The study was aimed to investigate the human leukocyte antigen (HLA)-A, B, DRB1 alleles and haplotype frequencies and the characteristics of linkage disequilibrium in north Chinese Han bone marrow donors. HLA phenotype data of 11 755 north Chinese Han bone marrow donors were identified by PCR-SSP and PCR-SSO. HLA-A, B, DRB1 allele and haplotype frequencies were calculated by computer software named Arleguin which was based on Expectation-Maximization (EM) algorithms. The results showed that the population of 11755 unrelated-donors was tested by Hardy-Weinberg equilibrium, and 18,42 and 15 specificities of HLA alleles were identified on the HLA-A, B, DRB1 locus respectively, including HLA-A25, B42, B53, B73 and DR3 which were rarely reported in Han population. HLA-A36, A43, A80, B78, B82 and DR18 were not detected in this study. The most frequent alleles with a frequency of over 0.05 were HLA-A*02, A*11, A*24, A*33, A*30, A*01, A*03, A*13, B62, B*51, B*46, B60, B61, B*35, B*44, DRB1*15, DRB1*09, DRB1*04, DRB1*07, DRB1*12, DRB1*11, DRB1*14, DRB1*08, DRB1*13. There were a total of 2 026 kinds of HLA-A-B-DR haplotypes (with a frequency of over 10(-6)) to be obtained. The each frequency of 26 kinds of three-locus haplotypes including HLA-A30-B13-DR7, A2-B46-DR9, A33-B58-DR17 etc was higher than 0.005. A30-B13-DR7 was the most frequent haplotype in north Chinese Han population. There were a total of 538 kinds of haplotypes for HLA-A-B, 227 kinds for A-DR and 522 kinds for B-DR to be obtained, and there were 409, 195, 423 kinds of haplotypes respectively with a frequency higher than 10 - 6. There were 28 kinds of HLA-A-B haplotypes including A30-B13, A2-B46, A33-B58 etc, 26 kinds of HLA-A-DR haplotypes including A2-DR9, A2-DR15, A30-DR7 etc, and 24 kinds of HLA-B-DR haplotypes including B13-DR7, B46-DR9, B13-DR12 etc with a frequency higher than 0.01. 296 (72%) kinds of HLA-A-B, 130 (67%) kinds of A-DR and 308 (73%) kinds of B-DR haplotypes were statistical linkage disequilibrium. HLA-A30-B13, A33-B58, A1-B37, A30-DR7, A33-DR13, A1-DR10, B37-DR10, B8-DR17, B13-DR7, B58-DR17 were significant positive linkage disequilibrium. It is concluded that this HLA-A, B, DRB1 gene and haplotype frequencies and linkage disequilibrium data with the largest sample size up to now is unique in north Chinese Han population. The study will be helpful to find matched donors for patients and establish the important foundation for further studying of transplantation immunity, HLA-related diseases and population genetics of this area.