Search

To figure out the molecular mechanism of aloperine (ALO) on receptor activator of nuclear factor (NF)-kappa-B (κb) ligand (RANKL)-caused osteoclast differentiation. The histopathological analysis and tartrate-resistant acid phosphatase (TRAP) staining assays were applied to check the extent of bone loss of the femur. Then, the protein expressions of nitric oxide synthase 2, glutathione reductase, nuclear erythroid 2-related factor 2, heme oxygenase-1, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1, and catalase were checked in RAW264.7, a macrophage cell line, by enzyme-linked-immunosorbent serologic assay and Western blot analysis. Further, the TRAP staining and quantitative polymerase chain reaction assay were applied to characterize the level of RAW264.7 osteoclast differentiation. Besides, Western blot assay was used to check the protein expressions of extracellular regulated protein kinases (ERK), c-Jun N-terminal kinase (JNK), and P38 in RAW264.7. Finally, ERK activation blocker U0126 was used to inhibit mitogen-activated protein kinase (MAPK) signaling pathway to determine the effect of MAPK signaling pathway on RAW264.7 osteoclast differentiation. In this study, the results demonstrated that ALO could inhibit lipopolysaccharide-induced bone loss in vivo in a dose-dependent manner, with significant inhibitory effects at high doses. Further research indicated that ALO could inhibit RANKL-induced oxidative stress and osteoclast differentiation of RAW264.7. Then, ALO could inactivate MAPK signaling pathway. Finally, the results showed that inhibition of MAPK signaling pathway could increase ALO inhibition of RANKL-caused osteoclast differentiation. ALO inhibits RANKL-caused osteoclast differentiation by suppressing the MAPK signaling pathways.

The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria. As an excellent candidate to overcome antibiotic resistance, antimicrobial peptides (AMPs) that are produced from the synthetic and natural sources demonstrate a broad-spectrum antimicrobial activity with the high specificity and low toxicity. These peptides possess distinctive structures and functions by employing sophisticated mechanisms of action. This comprehensive review provides a broad overview of AMPs from the origin, structural characteristics, mechanisms of action, biological activities to clinical applications. We finally discuss the strategies to optimize and develop AMP-based treatment as the potential antimicrobial and anticancer therapeutics. Supplementary Information The online version contains supplementary material available at 10.1186/s40779-021-00343-2.

Hyperactivation of oncogenic pathways downstream of RAS and PI3K/AKT in normal cells induces a senescence-like phenotype that acts as a tumor-suppressive mechanism that must be overcome during transformation. We previously demonstrated that AKT-induced senescence (AIS) is associated with profound transcriptional and metabolic changes. Here, we demonstrate that human fibroblasts undergoing AIS display upregulated cystathionine-β-synthase (CBS) expression and enhanced uptake of exogenous cysteine, which lead to increased hydrogen sulfide (H2S) and glutathione (GSH) production, consequently protecting senescent cells from oxidative stress-induced cell death. CBS depletion allows AIS cells to escape senescence and re-enter the cell cycle, indicating the importance of CBS activity in maintaining AIS. Mechanistically, we show this restoration of proliferation is mediated through suppressing mitochondrial respiration and reactive oxygen species (ROS) production by reducing mitochondrial localized CBS while retaining antioxidant capacity of transsulfuration pathway. These findings implicate a potential tumor-suppressive role for CBS in cells with aberrant PI3K/AKT pathway activation. Consistent with this concept, in human gastric cancer cells with activated PI3K/AKT signaling, we demonstrate that CBS expression is suppressed due to promoter hypermethylation. CBS loss cooperates with activated PI3K/AKT signaling in promoting anchorage-independent growth of gastric epithelial cells, while CBS restoration suppresses the growth of gastric tumors in vivo. Taken together, we find that CBS is a novel regulator of AIS and a potential tumor suppressor in PI3K/AKT-driven gastric cancers, providing a new exploitable metabolic vulnerability in these cancers.

The outcome of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) have greatly improved in tyrosine kinase inhibitors (TKIs) era and is just moving to a chemo-free era using dasatinib and blinatumomab (Foà R, N Engl J Med. 2020; Ravandi F, Blood. 2019). However, the outcome of T315I/compound-mutated Ph+ ALL patients is dismal (Cortes JE, N Engl J Med. 2013), representing an unmet need. Recently, Scherr et al reported the curative potential of venetoclax-TKIs-dexamethasone in a BCR-ABL+ mouse model (Scherr M, Leukemia. 2019). Here, we firstly reported outcome of 19 T315I/compound-mutated relapsed/refractory （R/R）Ph+ ALL patients treated with venetoclax(100mg d1, 200mg d2, 400mg d3-28), ponatinib (45mg d1-28) and dexamethasone (0.15mg/kg d1-21,0.075mg/kg d22-28）(VPD regimen) (Figure 1A) between January 2020 and May 2021. They had already received a median of 3 lines of salvage therapy. After one cycle, 17 patients (89.5%) achieved CR/CRi [13 minimal residual disease (MRD)--negative by flow cytometry;11 major molecular remission (MMR);8 complete molecular remission (CMR)] (Figure 1B). Subsequently relapse occurred in 1/6 [allogeneic hematopoietic cell transplantation (allo-HSCT) group)] and 7/11 (VDP consolidation group). At a median follow-up of 259 days, the median EFS and OS of patients from the starting VPD treatment was 242 and 400 days. Adverse events of VPD regimen were listed in Figure 1C. Grade 3-4 neutropenia, anemia and thrombocytopenia occurred in 73.7%,36.8% and 52.6% patients. 5.3% and 16% patients have grade 3-4 rash and infection separately. No tumor lysis syndrome or death occurred. 7/19 patients were treated safety outpatient. Moreover, venetoclax had a strong synergistic effect with ponatinib and dexamethasone on inducing apoptosis of primary blast cells and BaF3 cells expressing p190 BCR/ABL with T315I-mutation in vitro, with a combination index of 0.019 when the suppressing rate is 0.05, while the effect was significant decreased when ponatinib was replaced by dasatinib (Figure 1D-F), a prominent change of mitochondrial membrane potential as well as the cleavage of PARP were also observed in triple-combination treatment group (Figure 1G-H). For T315I/compound-mutated Ph+ ALL, VPD regimen exhibited 89.5% CR/CRi rate, with deep molecular remission (57.9% MMR), while ponatinib alone showed 41% hematologic response (Cortes JE, N Engl J Med. 2013), which supported by the preclinical data suggesting TKIs and venetoclax are highly synergistic in BCR-ABL + cells in vitro (Scherr M, Leukemia. 2019). 7/11 and 1/6 patients subsequently relapsed in continuous VPD and allo-HSCT postremission treatment group separately, suggested bridging to allo-HSCT after remission is warranted. Moreover, novel compounds such as blinatumomab showed a preliminary efficacy (Couturier MA, Leuk Lymphoma. 2021). In summary, VPD regimen provides a novel treatment for T315I/compound-mutated R/R Ph+ALL under a complete oral and chemo-free model. A clinical trial also using similar VPD regimen for treatment of R/R Ph+ ALL is ongoing now (Short NJ, Am J Hematol. 2021). Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Purpose Acute myeloid leukemia (AML) is a complex malignancy characterized by the clonal expansion of immature myeloid precursors. The standard treatment for newly diagnosed AML is chemotherapy consisting of cytosine arabinoside (Ara-C) and anthracyclines with disappointing clinical outcomes and severe adverse effects, such as symptomatic bradycardia, neurotoxicity. Thus, it is promising to treat AML through combination drug therapy to reduce the adverse effects of chemotherapeutics. In our recent published PNAS paper, we reported that NK-1R antagonists, both Aprepitant and SR140333, induce apoptosis of myeloid leukemia cells by inducing oxidative stress through mitochondrial calcium overload. We, therefore, tested the hypothesis of the combination Ara-C with NK-1R antagonist could enhance the efficacy of Ara-C. Methods MTT assay was employed to detect the cell proliferation. Flow cytometry was applied to detect the cell cycle and necrosis. PI uptake and LDH release assay were used to detect the disintegration of the plasma membrane. Xenograft model was constructed to explore the effect of combination Ara-C with Aprepitant in vivo. Results Our results showed that Aprepitant sensitizes HL60 cells to the cytotoxic effects of Ara-C more than 5-fold by enhancing G0/G1 cell cycle arrest and necrosis in vitro. Furthermore, Nec-1, a specific inhibitor of necroptosis, could recover the cell proliferative viability significantly. Attractively, once every 2-days regimen of Ara-C (5 mg/kg) and Aprepitant (10 mg/kg) via in situ injection dramatically reduced the tumor volume from 2175.0 ± 341.9 mm3 in the vehicle group to 828.4 ± 232.4 mm3 in the combination group without obvious toxicity in human myeloid leukemia xenograft mice. Conclusion Taken together, reduced dose of Ara-C combination with moderate Aprepitant provides more effective therapeutical methods for AML treatment in vitro and in vivo with the elimination of the toxicity of Ara-C, which may pay new avenue for the usage of the routine chemotherapy drug Ara-C with low dose to enhance efficacy and reduce toxicity in clinical practice.

The neurokinin‐1 receptor (NK‐1R) antagonists are approved as treatment for chemotherapy‐associated nausea and vomiting in cancer patients. The emerging role of the substance P‐NK‐1R system in oncogenesis raises the possibility of repurposing well‐tolerated NK‐1R antagonists for cancer treatment. This study reports that human colorectal cancer (CRC) patients with high NK‐1R expression have poor survival, and NK‐1R antagonists SR140333 and aprepitant induce apoptotic cell death in CRC cells and inhibit CRC xenograft growth. This cytotoxicity induced by treatment with NK‐1R antagonists is mediated by induction of endoplasmic reticulum (ER) stress. ER stress triggers calcium release, resulting in the suppression of prosurvival extracellular signal‐regulated kinase (ERK)‐c‐Myc signaling. Along with ER calcium release, one ER stress pathway mediated by protein kinase RNA‐like ER kinase (PERK) is specifically activated, leading to increased expression of proapoptotic C/EBP‐homologous protein (CHOP). Moreover, NK‐1R antagonists enhance the efficacy of chemotherapy by increasing the sensitivity and overcoming resistance to 5‐fluorouracil in CRC cells through the induction of sustained ER stress and the consequent suppression of ERK‐c‐Myc signaling both in vitro and in vivo. Collectively, the findings provide novel mechanistic insights into the efficacy of NK‐1R antagonists either as a single agent or in combination with chemotherapy for cancer treatment., The neurokinin‐1 receptor antagonists are repurposed as a new treatment option for patients with colorectal cancer via activation of endoplasmic reticulum stress to induce apoptosis.

Annexin A1 is a Ca2+-dependent phospholipid binding protein involved in a variety of pathophysiological processes. Accumulated evidence has indicated that Annexin A1 has important functions in cell proliferation, apoptosis, differentiation, metastasis, and inflammatory response. Moreover, the abnormal expression of Annexin A1 is closely related to the occurrence and development of tumors. In this review article, we focus on the structure and function of Annexin A1 protein, especially the recent evidence of Annexin A1 in the pathophysiological role of inflammatory and cancer. This summary will be very important for further investigation of the pathophysiological role of Annexin A1 and for the development of novel therapeutics of inflammatory and cancer based on targeting Annexin A1 protein.

Identification of the role of the MC1R gene has provided major insights into variation in skin pigmentation in several organisms, including humans, but the evolutionary genetics of this variation is less well established. Variation in this gene and its relationship with degree of melanism was analyzed in one of the world’s highest-elevation lizards, Phrynocephalus theobaldi from the Qinghai–Tibetan Plateau. Individuals from the low-elevation group were shown to have darker dorsal pigmentation than individuals from a high-elevation group. The existence of climatic variation across these elevations was quantified, with lower elevations exhibiting higher air pressure, temperatures, and humidity, but less wind and insolation. Analysis of the MC1R gene in 214 individuals revealed amino acid differences at five sites between intraspecific sister lineages from different elevations, with two sites showing distinct fixed residues at low elevations. Three of the four single-nucleotide polymorphisms that underpinned these amino acid differences were highly significant outliers, relative to the generalized MC1R population structuring, suggestive of selection. Transfection of cells with an MC1R allele from a lighter high-elevation population caused a 43% reduction in agonist-induced cyclic AMP accumulation, and hence lowered melanin synthesis, relative to transfection with an allele from a darker low-elevation population. The high-elevation allele led to less efficient integration of the MC1R protein into melanocyte membranes. Our study identifies variation in the degree of melanism that can be explained by four or fewer MC1R substitutions. We establish a functional link between these substitutions and melanin synthesis and demonstrate elevation-associated shifts in their frequencies.

Purpose Acute myeloid leukemia (AML) is a complex malignancy characterized by the clonal expansion of immature myeloid precursors. The standard treatment for newly diagnosed AML is chemotherapy consisting of cytosine arabinoside (Ara-C) and anthracyclines with disappointing clinical outcomes and severe adverse effects, such as symptomatic bradycardia, neurotoxicity. Thus, it is promising to treat AML through combination drug therapy to reduce the adverse effects of chemotherapeutics. In our recent published PNAS paper, we reported that NK-1R antagonists, both Aprepitant and SR140333, induce apoptosis of myeloid leukemia cells by inducing oxidative stress through mitochondrial calcium overload. We, therefore, tested the hypothesis of the combination Ara-C with NK-1R antagonist could enhance the efficacy of Ara-C. Methods MTT assay was employed to detect the cell proliferation. Flow cytometry was applied to detect the cell cycle and necrosis. PI uptake and LDH release assay were used to detect the disintegration of the plasma membrane. Xenograft model was constructed to explore the effect of combination Ara-C with Aprepitant in vivo. Results Our results showed that Aprepitant sensitizes HL60 cells to the cytotoxic effects of Ara-C more than 5-fold by enhancing G0/G1 cell cycle arrest and necrosis in vitro. Furthermore, Nec-1, a specific inhibitor of necroptosis, could recover the cell proliferative viability significantly. Attractively, once every 2-days regimen of Ara-C (5 mg/kg) and Aprepitant (10 mg/kg) via in situ injection dramatically reduced the tumor volume from 2175.0 ± 341.9 mm3 in the vehicle group to 828.4 ± 232.4 mm3 in the combination group without obvious toxicity in human myeloid leukemia xenograft mice. Conclusion Taken together, reduced dose of Ara-C combination with moderate Aprepitant provides more effective therapeutical methods for AML treatment in vitro and in vivo with the elimination of the toxicity of Ara-C, which may pay new avenue for the usage of the routine chemotherapy drug Ara-C with low dose to enhance efficacy and reduce toxicity in clinical practice.

Acidic vesicles and organelles play fundamental roles in a broad range of cellular events such as endocytosis, lysosomal degradation, synaptic transmission, pathogen fate, and drug delivery. Fluorescent reporters will be invaluable for studying these complex and multifunctional systems with spatiotemporal resolution, yet common fluorescent proteins are generally nonfluorescent at acidic conditions due to the decrease of anionic chromophores upon protonation, but are fluorescent at physiological pH, creating interfering fluorescence from nonvesicle regions. Here we developed a novel acid-brightening fluorescent protein (abFP) that fluoresces strongly at acidic pH but is nonfluorescent at or above neutral pH, boasting a pH profile opposite to that of common fluorescent proteins. Through expansion of the genetic code, we incorporated a quinoline-containing amino acid Qui into the chromophore of EGFP to reverse the chromophore charge. Protonation of Qui rendered a cationic chromophore, which resulted in unique fluorescence increase only at acidic pH in vitro, in E. coli cells, and on the mammalian cell surface. We further demonstrated that abFP-tagged δ opioid receptors were fluorescently imaged in lysosome showing distinct features and without background fluorescence from other cellular regions, whereas EGFP-tagged receptors were invisible in lysosome. This Qui-rendered cationic chromophore strategy may be generally applied to other fluorescent proteins to generate a palette of colors for acidic imaging with minimal background, and these abFPs should facilitate the study of molecules in association with various acidic vesicles and organelles in different cells and model organisms.

Mouse animal models are the most commonly used experimental tools in scientific research, which have been widely favored by researchers. The animal model of mouse leukemia appeared in the 1930s. During the past 90 years, researchers have developed various types of mouse leukemia models to simulate the development and treatment of human leukemia in order to promote effectively the elucidation of the molecular mechanism of leukemia' development and progression, as well as the development of targeted drugs for the treatment of leukemia. Considering that to myeloid leukemia, especially acute myeloid leukemia, there currently is no good clinical treatment, it is urgent to clarify its new molecular mechanism and develop new therapeutic targets. This review focuses on the various types of mouse models about myeloid leukemia used commonly in recent years, including mouse strains, myeloid leukemia cell types, and modeling methods, which are expected to provide a reference for relevant researchers to select animal models during myeloid leukemia research.小鼠动物模型作为科学研究中最常用的实验工具，在两个世纪的发展中受到了研究人员的广泛青睐。小鼠白血病动物模型出现于 20 世纪 30 年代，在近 90 年的发展过程中，研究者们开发出了多种类型的小鼠白血病模型来模拟人类白血病的发生发展和药物治疗过程，这在一定程度上推动了白血病发生发展分子机制的阐明和靶向治疗白血病药物的研发进程。考虑到髓系白血病，特别是急性髓系白血病目前在临床上没有很好的治疗措施，急需阐明其新的分子机制和开发新的治疗靶点，本文重点综述了近几年最常用的髓系白血病小鼠模型，包括小鼠品系、髓系白血病细胞类型、成模方式等，以期为相关科研工作者在髓系白血病研究过程中选择动物模型时提供一定的参考。.

Significance Despite tremendous efforts in developing effective therapeutics for treating acute myeloid leukemia (AML), this hematological disease remains an incurable malignancy. Here, we show surprising findings that neurokinin-1 receptor (NK-1R) is highly expressed in AML patients and that targeting NK-1R produced potent proapoptotic and antinociceptive effects. Given the clinical availability of the NK-1R antagonists for treating chemotherapy-induced adverse effects, the therapeutic effect of the NK-1R antagonists could be readily tested in human patients with myeloid leukemia. If the therapeutic effect is successfully validated in human patients, our findings would bring hope and benefits for millions of patients. Our study provides another example of drug discovery by mechanistic efforts., Substance P (SP) regulates multiple biological processes through its high-affinity neurokinin-1 receptor (NK-1R). While the SP/NK-1R signaling axis is involved in the pathogenesis of solid cancer, the role of this signaling pathway in hematological malignancy remains unknown. Here, we demonstrate that NK-1R expression is markedly elevated in the white blood cells from acute myeloid leukemia patients and a panel of human leukemia cell lines. Blocking NK-1R induces apoptosis in vitro and in vivo via increase of mitochondrial reactive oxygen species. This oxidative stress was triggered by rapid calcium flux from the endoplasmic reticulum into mitochondria and, consequently, impairment of mitochondrial function, a mechanism underlying the cytotoxicity of NK-1R antagonists. Besides anticancer activity, blocking NK-1R produces a potent antinociceptive effect in myeloid leukemia-induced bone pain by alleviating inflammation and inducing apoptosis. These findings thus raise the exciting possibility that the NK-1R antagonists, drugs currently used in the clinic for preventing chemotherapy-induced nausea and vomiting, may provide a therapeutic option for treating human myeloid leukemia.

Stem cell therapy may replace lost photoreceptors and preserve residual photoreceptors during retinal degeneration (RD). Unfortunately, the degenerative microenvironment compromises the fate of grafted cells, demanding supplementary strategies for microenvironment regulation. Donor cells with both proper regeneration capability and intrinsic ability to improve microenvironment are highly desired. Here, we use cell surface markers (C-Kit+/SSEA4−) to effectively eliminate tumorigenic embryonic cells and enrich retinal progenitor cells (RPCs) from human embryonic stem cell (hESC)-derived retinal organoids, which, following subretinal transplantation into RD models of rats and mice, significantly improve vision and preserve the retinal structure. We characterize the pattern of integration and materials transfer following transplantation, which likely contribute to the rescued photoreceptors. Moreover, C-Kit+/SSEA4− cells suppress microglial activation, gliosis and the production of inflammatory mediators, thereby providing a healthier host microenvironment for the grafted cells and delaying RD. Therefore, C-Kit+/SSEA4− cells from hESC-derived retinal organoids are a promising therapeutic cell source., Stem cell transplantation to treat retinal degeneration could be limited by the degenerative microenvironment. Here, the authors show that C-Kit+/SSEA4– progenitor cells enriched from human embryonic stem cell derived retinal organoids protect retinal structure, suppress microglial activation, gliosis and inflammation.

Yu Zou,1,2 Chuan-Gen Guo,2 Zheng-Gang Yang,3 Jun-Hui Sun,4 Min-Ming Zhang,5 Cai-Yun Fu6,71Department of Radiology, Women’s Hospital, School of Medicine, Zhejiang University, 2Department of Radiology, First Affiliated Hospital, School of Medicine, Zhejiang University, 3Institute of Infectious Diseases, First Affiliated Hospital, School of Medicine, Zhejiang University, 4Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, 5Department of Radiology, Second Affiliated Hospital, School of Medicine, Zhejiang University, 6College of Life Sciences, Zhejiang Sci-Tech University, 7Key Laboratory of Cell-Based Drug and Applied Technology Development in Zhejiang Province, Hangzhou, People’s Republic of China Introduction: Hepatocellular carcinoma is currently the second leading cause of cancer-related deaths worldwide with an increasing incidence.Objective: The objective of this study is to investigate the effect of vascular endothelial growth factor small interfering RNA (VEGF-siRNA) on rabbit VX2 carcinoma cell viability in vitro and the effect of transarterial embolization (TAE)-mediated VEGF-siRNA delivery on the growth of rabbit VX2 liver-transplanted model in vivo.Methods: Quantitative reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot technologies were used to detect the expression level of VEGF. TAE and computed tomography scan were used to deliver the VEGF-siRNA and detect the tumor volume in vivo, respectively. Microvessel density was detected by immunohistochemistry with CD34 antibody. A biochemical autoanalyzer was used to evaluate the hepatic and renal toxicity.Results: The designed VEGF-siRNAs could effectively decrease the expression levels of VEGF mRNA and protein in vitro and in vivo. In vitro, the viability of rabbit VX2 carcinoma cells was reduced by 38.5%±7.3% (VEGF-siRNA no 1) and 30.0%±5.8% (VEGF-siRNA no 3) at 48hours after transfection. Moreover, in rabbit VX2 liver-transplanted model, the growth ratios of tumors at 28days after TAE-mediated siRNA delivery were 155.18%±19.42% in the control group, 79.67%±19.63% in the low-dose group, and 36.09%±15.73% in the high-dose group, with significant differences among these three groups. Microvessel density dropped to 34.22±4.01 and 22.63±4.07 in the low-dose group and high-dose group, respectively, compared with the control group (57.88±5.67), with significant differences among these three groups. Furthermore, inoculation of VX2 tumor into the liver itself at later stage induced significant increase in alanine aminotransferase and aspartate aminotransferase, indicating an obvious damage of liver functions, while treatment of VX2 tumor via TAE-mediated VEGF-siRNA had no toxicity to the livers and kidneys of rabbits, and VEGF-siRNA had the ability to protect liver damage induced by tumor growth.Conclusion: This is the first study to demonstrate that targeting VEGF via TAE-mediated siRNA delivery may become a powerful new option for effective treatment of hepatocellular carcinoma in the clinic.Keywords: hepatocellular carcinoma, VEGF-siRNAs, CT scan, microvessel density, toxicity to the livers and kidneys

Cell death is an essential biological process for physiological growth and development. Three classical forms of cell death—apoptosis, autophagy, and necrosis—display distinct morphological features by activating specific signaling pathways. With recent research advances, we have started to appreciate that these cell death processes can cross-talk through interconnecting, even overlapping, signaling pathways, and the final cell fate is the result of the interplay of different cell death programs. This review provides an insight into the independence of and associations among these three types of cell death and explores the significance of cell death under the specific conditions of human diseases, particularly neurodegenerative diseases and cancer., Targeting the interconnections of cell death to treat disease New understandings of the interconnectivity of cell death pathways could provide novel therapeutic targets for cancer and neurodegenerative diseases like Alzheimer’s. Caiyun Fu of China’s Zhejiang Sci-Tech University and colleagues reviewed the latest research into the mechanisms and connections between the different types of cell death. Apoptosis, ‘programmed’ cell death; necrosis, ‘accidental’ cell death; and autophagy, the means by which cells destroy damaged internal organelles, each has independent molecular mechanisms that can also be simultaneously activated, operating in parallel in response to stress. Targeting these interconnected mechanisms with drugs could treat neurodegenerative diseases like Alzheimer’s and Parkinson’s, in which deregulated cell death plays a major role, and cancer, in which highly proliferating cells escape death pathways.

Introducing new chemical reactivity into proteins in living cells would endow innovative covalent bonding ability to proteins for research and engineering in vivo. Latent bioreactive unnatural amino acids (Uaas) can be incorporated into proteins to react with target natural amino acid residues via proximity-enabled reactivity. To expand the diversity of proteins amenable to such reactivity in vivo, a chemical functionality that is biocompatible and able to react with multiple natural residues under physiological conditions is highly desirable. Here we report the genetic encoding of fluorosulfate-l-tyrosine (FSY), the first latent bioreactive Uaa that undergoes sulfur-fluoride exchange (SuFEx) on proteins in vivo. FSY was found nontoxic to Escherichia coli and mammalian cells; after being incorporated into proteins, it selectively reacted with proximal lysine, histidine, and tyrosine via SuFEx, generating covalent intraprotein bridge and interprotein cross-link of interacting proteins directly in living cells. The proximity-activatable reactivity, multitargeting ability, and excellent biocompatibility of FSY will be invaluable for covalent manipulation of proteins in vivo. Moreover, genetically encoded FSY hereby empowers general proteins with the next generation of click chemistry, SuFEx, which will afford broad utilities in chemical biology, drug discovery, and biotherapeutics.

Background Despite diverse pathogenesis, the common pathological change observed in age-related macular degeneration and in most hereditary retinal degeneration (RD) diseases is photoreceptor loss. Photoreceptor replacement by cell transplantation may be a feasible treatment for RD. The major obstacles to clinical translation of stem cell-based cell therapy in RD remain the difficulty of obtaining sufficient quantities of appropriate and safe donor cells and the poor integration of grafted stem cell-derived photoreceptors into the remaining retinal circuitry. Methods Eye-wall c-kit+/stage-specific embryonic antigen 1 (SSEA1)− cells were isolated via fluorescence-activated cell sorting, and their self-renewal and differentiation potential were detected by immunochemistry and flow cytometry in vitro. After labeling with quantum nanocrystal dots and transplantation into the subretinal space of rd1 RD mice, differentiation and synapse formation by daughter cells of the eye-wall c-kit+/SSEA1− cells were evaluated by immunochemistry and western blotting. Morphological changes of the inner retina of rd1 mice after cell transplantation were demonstrated by immunochemistry. Retinal function of rd1 mice that received cell grafts was tested via flash electroretinograms and the light/dark transition test. Results Eye-wall c-kit+/SSEA1− cells were self-renewing and clonogenic, and they retained their proliferative potential through more than 20 passages. Additionally, eye-wall c-kit+/SSEA1− cells were capable of differentiating into multiple retinal cell types including photoreceptors, bipolar cells, horizontal cells, amacrine cells, Müller cells, and retinal pigment epithelium cells and of transdifferentiating into smooth muscle cells and endothelial cells in vitro. The levels of synaptophysin and postsynaptic density-95 in the retinas of eye-wall c-kit+/SSEA1− cell-transplanted rd1 mice were significantly increased at 4 weeks post transplantation. The c-kit+/SSEA1− cells were capable of differentiating into functional photoreceptors that formed new synaptic connections with recipient retinas in rd1 mice. Transplantation also partially corrected the abnormalities of inner retina of rd1 mice. At 4 and 8 weeks post transplantation, the rd1 mice that received c-kit+/SSEA1− cells showed significant increases in a-wave and b-wave amplitude and the percentage of time spent in the dark area. Conclusions Grafted c-kit+/SSEA1− cells restored the retinal function of rd1 mice via regulating neural plasticity and forming new graft-to-host synapses.

Paclitaxel, one of the broadest-spectrum anticancer agents, is currently being used in the treatment of patients with solid tumors. In the present study, we compared the effect of paclitaxel on two types of leukemia cells. Our results showed that paclitaxel could inhibit the proliferation of MEL and K562 cells in a dose- and time-dependent manner. The mechanism of proliferative inhibition in K562 cells treated by paclitaxel was related to the cell cycle arrest in the G2/M phase, as well as the induction of apoptosis. By contrast, MEL cells treated by paclitaxel showed significant characteristics of necrosis, which indicated that the mode of cell death induced by paclitaxel in these two types of leukemia cells differed. Advances in research of the cell cycle, apoptosis and necrosis will extend our understanding of the mechanisms of paclitaxel-induced cell death, particularly in leukemia cells. Further elucidation of the mechanisms of necrosis in MEL cells may expedite the development of improved paclitaxel-based regimens for cancer therapy.

Hemokinin-1 is a peptide encoded by Pptc, which belongs to the family of mammalian tachykinins. Our previous results showed that rat/mouse hemokinin-1 (r/m HK-1) produced striking analgesia after intracerebroventricular (i.c.v.) injection in mice, and the analgesia could be blocked by the NK1 receptor antagonist and the opioid receptor antagonist, respectively. However, the precise distribution sites and the molecular mechanism involved in the analgesic effect after i.c.v. administration of r/m HK-1 are needed to be further investigated deeply. Using the fluorescence labeling method, our present results directly showed that r/m HK-1 peptides were mainly distributed at the ventricular walls and several juxta-ventricular structures for the first time. Our results showed that the mRNA expressions of NK1 receptor, PPT-A, PPT-C, KOR, PDYN, DOR and PENK were not changed markedly, as well as the protein expression of NK1 receptor was hardly changed. However, both the transcripts and proteins of MOR and POMC were up-regulated significantly, indicating that the analgesic effect induced by i.c.v. administration of r/m HK-1 is related to the activation of NK1 receptor first, then it is related to the release of endogenous proopiomelanocortin, as well as the increased expression level of μ opioid receptor. These results should facilitate further the analysis of the analgesia of r/m HK-1 in the central nerval system in acute pain and may open novel pharmacological interventions.

The vertebrate retina is a highly multilayered nervous tissue with a large diversity of cellular components. With the development of stem cell technologies, human retinas can be generated in three-dimensional (3-D) culture in vitro. However, understanding the factors modulating key productive processes and the way that they influence development are far from clear. Oxygen, as the most essential element participating in metabolism, is a critical factor regulating organic development. In this study, using 3-D culture of human stem cells, we examined the effect of intermittent high oxygen treatment (40% O2) on the formation and cellular behavior of neural retinas (NR) in the embryonic body (EB). The volume of EB and number of proliferating cells increased significantly under 40% O2 on day 38, 50 and 62. Additionally, the ratio of PAX6+ cells within NR was significantly increased. The neural rosettes could only develop with correct apical-basal polarity under 40% O2. In addition, the generation, migration and maturation of retinal ganglion cells were enhanced under 40% O2. All of these results illustrated that 40% O2 strengthened the formation of NR in EB with characteristics similar to the in vivo state, suggesting that the hyperoxic state facilitated the retinal development in vitro.

LF11-322 (PFWRIRIRR-NH2) (PFR peptide), a nine amino acid-residue peptide fragment derived from human lactoferricin, possesses potent cytotoxicity against bacteria. We report here the discovery and characterization of its antitumor activity in leukemia cells. PFR peptide inhibited the proliferation of MEL and HL-60 leukemia cells by inducing cell death in the absence of the classical features of apoptosis, including chromatin condensation, Annexin V staining, Caspase activation and increase of abundance of pro-apoptotic proteins. Instead, necrotic cell death as evidenced by increasing intracellular PI staining and LDH release, inducing membrane disruption and up-regulating intracellular calcium level, was observed following PFR peptide treatment. In addition to necrotic cell death, PFR peptide also induced G0/G1 cell cycle arrest. Moreover, PFR peptide exhibited favorable antitumor activity and tolerability in vivo. These findings thus provide a new clue of antimicrobial peptides as a potential novel therapy for leukemia.

With the technological advances in cancer diagnosis and treatment, the survival rates for patients with cancer are prolonged. The issue of figuring out how to improve the life quality of patients with cancer has become increasingly prominent. Pain, especially bone pain, is the most common symptom in malignancy patients, which seriously affects the life quality of patients with cancer. The research of cancer pain has a breakthrough due to the development of the animal models of cancer pain in recent years, such as the animal models of mouse femur, humerus, calcaneus, and rat tibia. The establishment of several kinds of animal models related to cancer pain provides a new platform in vivo to investigate the molecular mechanisms of cancer pain. In this review, we focus on the advances of cancer pain from bone metastasis, the mechanisms involved in cancer pain, and the drug treatment of cancer pain in the animal models.

Bone pain is a common and severe symptom in cancer patients. The present study employed a mouse model of leukemia bone pain by injection K562 cells into tibia of mouse to evaluate the analgesic effects of lappacontine. Our results showed that the lappaconitine treatment at day 15, 17 and 19 could effectively reduce the spontaneous pain scoring values, restore reduced degree in the inclined-plate test induced by injection of K562 cells, as well as restore paw mechanical withdrawal threshold and paw withdrawal thermal latency induced by injection of K562 cells to the normal levels. Additionally, the molecular mechanisms of lappaconitine’s analgesic effects may be related to affect the expression levels of endogenous opioid system genes (POMC, PENK and MOR), as well as apoptosis-related genes (Xiap, Smac, Bim, NF-κB and p53). Our present results indicated that lappaconitine may become a new analgesic agent for leukemia bone pain management.

Electric field stimulation (EFS) causes excitatory non adrenergic-non cholinergic (eNANC) and cholinergic constrictions in the guinea pig isolated bronchus, the activation of eNANC and cholinergic nerves respectively. We investigated the effects of [Nphe1]nociceptin(1-13)NH2 ([Nphe1]NC(1-13)NH2), [Phe1(CH2-NH)Gly2]nociceptin(1- 13)NH2 ([F/G] NC(1-13)NH2), and nocistatin (NST) on nociceptin (NC) inhibited constrictions in isolated bronchus of guinea pig. The results show that NC (1 micromol/L) inhibited EFS-induced eNANC and cholinergic constrictions compared with the control, in which nociceptin was not applied. After pretreatment with [Nphe1]NC(1-13)NH2, [F/G]NC(1-13)NH2, or NST, the inhibitions of NC were antagonized by [Nphe1]NC(1-13)NH2 and [F/G]NC(1-13)NH2 but not NST. However, [Nphe1]NC(1-13)NH2, [F/G]NC(1-13)NH2, and NST did not affect the inhibitions induced by morphine. Furthermore, [Nphe1]NC(1-13)NH2, [F/G]NC(1-13)NH2 and NST did not cause any appreciable effects on EFS-induced eNANC and cholinergic constrictions in guinea pig bronchi. The results demonstrate that [Nphe1]NC(1-13)NH2 and [F/G]NC(1- 13)NH2 but not NST act as selective antagonists of the NC receptor and the effects of NC on EFS-induced constrictions of guinea pig isolated bronchus.

Recent phylogenetic researches discovered no reciprocal monophyly between morphological species of Phrynocephalus putjatia and P. guinanensis, P. guinanensis exhibits extensive sexual color dimorphism, whereas P. putjatia does not have. The complete mitochondrial genome of the putative taxa, Phrynocephalus guinanensis, was determined in order to compare the mitogenomes of both ecological forms. The mitogenome sequence was 16,279 bp in size. It consists of 13 protein-coding, 22 tRNA, 2 rRNA genes and 3 control region, and its gene order and gene content were identical with the mitogenome of P. putjatia.

Our previous studies have shown that an active fragment of human tachykinins (hHK-1(4-11)) produced an opioid-independent analgesia after intracerebroventricular (i.c.v.) injection in mice, which has been markedly enhanced by a δ OR antagonist, naltrindole hydrochloride (NTI). In this study, we have further characterized the in vivo analgesia after i.c.v. injection of hHK-1(4-11) in mouse model. Our qRT-PCR results showed that the mRNA levels of several ligands and receptors (e.g. PPT-A, PPT-C, KOR, PDYN and PENK) have not changed significantly. Furthermore, neither transcription nor expression of NK1 receptor, MOR and POMC have changed noticeably. In contrast, both mRNA and protein levels of DOR have been up-regulated significantly, indicating that the enhanced expression of δ opioid receptor negatively modulates the analgesia induced by i.c.v. injection of hHK-1(4-11). Additionally, the combinatorial data from our previous and present experiments strongly suggest that the discriminable distribution sites in the central nervous system between hHK-1(4-11) and r/mHK-1 may be attributed to their discriminable analgesic effects. Altogether, our findings will not only contribute to the understanding of the complicated mechanisms regarding the nociceptive modulation of hemokinin-1 as well as its active fragments at supraspinal level, but may also lead to novel pharmacological interventions.