Biology subjects

Zhang, L.

Publications and source records attributed to Zhang, L..

At least 1,441 records · Page 80Linked to original sources

bioRxiv2020

Infrared heater warming system markedly reduces dew formation: An overlooked factor in arid ecosystems

Dew plays a vital role in ecosystem processes in arid and semi-arid regions and is expected to be affected by climate warming. Infrared heater warming systems have been widely used to simulate climate warming effects on ecosystem. However, how this warming system affects dew formation has been long ignored and rarely addressed. In a typical alpine grassland ecosystem on the Northeast of the Tibetan Plateau, we measured dew amount and duration by artificial condensing surfaces, leaf wetness sensors and in situ dew formation on plants from 2012 to 2017. We also measured plant traits related to dew conditions. The results showed that (1) warming reduced the dew amount by 41.6%-91.1% depending on the measurement method, and reduced dew duration by 32.1 days compared to the ambient condition. (2) Different plant functional groups differed in dew formation. (3) Under the infrared warming treatment, the dew amount decreased with plant height, while under the ambient conditions, the dew amount showed the opposite trend. We concluded that warming with an infrared heater system greatly reduces dew formation, and if ignored, it may lead to overestimation of the effects of climate warming on ecosystem processes in climate change simulation studies.

ecology↗

bioRxiv2020

Single-cell ATAC-seq clustering and differential analysis by convolution-based approach

Technical improvement in ATAC-seq makes it possible to profile the chromatin states of single cells at high throughput, but currently no method is available to integrate datasets from multiple sources (different batches of same protocol or multiple experimental protocols). Here we present an algorithm to perform joint analyses on scATAC-seq datasets from multiple sources. In addition to batch correction, we also demonstrate that epiConv is capable of aligning co-assay data (simultaneous profiling of transcriptome and chromatin) onto high-quality ATAC-seq reference or integrating cells in different biological conditions (malignant vs. normal), which increases the statistical power of downstream analyses and reveals hidden hierarchy of malignant cells.

bioinformatics↗

bioRxiv2020

Reconstruction of cell spatial organization based on ligand-receptor mediated self-assembly

Single-cell RNA sequencing (scRNA-seq) has revolutionized transcriptomic studies by providing unprecedented cellular and molecular throughputs, but spatial information of individual cells is lost during tissue dissociation. While imaging-based technologies such as in situ sequencing show great promise, technical difficulties currently limit their wide usage. Since cellular spatial organization is inherently encoded by cell identity and can be reconstructed, at least in part, by ligand-receptor interactions, here we present CSOmap, a computational strategy to infer cellular interaction from scRNA-seq. We show that CSOmap can successfully recapitulate the spatial organization of tumor microenvironments for multiple cancers and reveal molecular determinants of cellular interactions. Further, CSOmap readily simulates perturbation of genes or cell types to gain novel biological insights, especially into how immune cells interact in the tumor microenvironment. CSOmap can be widely applicable to interrogate cellular organizations based on scRNA-seq data for various tissues in diverse systems.

bioinformatics↗

bioRxiv2020

Alpha-ketoamides as broad-spectrum inhibitors of coronavirus and enterovirus replication

The main protease of coronaviruses and the 3C protease of enteroviruses share a similar active-site architecture and a unique requirement for glutamine in the P1 position of the substrate. Because of their unique specificity and essential role in viral polyprotein processing, these proteases are suitable targets for the development of antiviral drugs. In order to obtain near-equipotent, broad-spectrum antivirals against alphacoronaviruses, betacoronaviruses, and enteroviruses, we pursued structure-based design of peptidomimetic -ketoamides as inhibitors of main and 3C proteases. Six crystal structures of protease:inhibitor complexes were determined as part of this study. Compounds synthesized were tested against the recombinant proteases as well as in viral replicons and virus-infected cell cultures; most of them were not cell-toxic. Optimization of the P2 substituent of the -ketoamides proved crucial for achieving near-equipotency against the three virus genera. The best near-equipotent inhibitors, 11u (P2 = cyclopentylmethyl) and 11r (P2 = cyclohexylmethyl), display low-micromolar EC50 values against enteroviruses, alphacoronaviruses, and betacoronaviruses in cell cultures. In Huh7 cells, 11r exhibits three-digit picomolar activity against Middle East Respiratory Syndrome coronavirus.

biochemistry↗

bioRxiv2020

Validity of Two-Dimensional Static Footprint in Medial Longitudinal Arch Evaluation and the Characteristics of Athletes' Footprints

BackgroundWe aimed to explore the validity of two-dimensional static footprint analysis in medial longitudinal arch evaluation as well as the characteristics of athletes footprints to provide a basis for the evaluation and selection of athletes. MethodsExperiment One: Twenty-nine high level athletes (runners and jumpers) and forty normal college students were selected. Based on the X-ray photos taken of the medial foot, we measured the calcaneal inclination angle, the calcaneal-first metatarsal angle and the ratio of height to length of the medial longitudinal arch. We collected indicators of two-dimensional static footprints. Experiment Two: 106 high level athletes (runners and jumpers) and 104 normal college students were selected. We also collected indicators of two-dimensional static footprints. ResultsThe average measuring the Interclass Correlation Efficient (ICC) of calcaneal inclination angle, calcaneal-first metatarsal angle, the ratio of height to length of the medial longitudinal arch, the width of ball, arch and heel, the length of footprint and each toe, Chippaux-Smirak Index (CSI) and Staheli Index (SAI) were higher than 0.800. Regardless of athletes or college students, male or female, the correlation between CSI, SAI and calcaneal inclination angle, calcaneal-first metatarsal angle, the ratio of height to length of the medial longitudinal arch was statistically significant (P<0.05). College students CSI of the right foot is significantly higher than that of the left foot regardless of gender (P<0.05). ConclusionsWe prove the qualification of CSI and SAI in medial longitudinal arch evaluation and explain that the relative height of medial longitudinal arch is an important indicator in track and field.

genetics↗

bioRxiv2020

Short chain fatty acid butyrate promotes virus infection by repressing interferon stimulated genes

Butyrate is an abundant metabolite produced by the gut microbiota and is known to modulate multiple immune system pathways and inflammatory diseases. However, studies of its effects on virus infection of cells are limited and enigmatic. We found that butyrate increases cellular infection and virus replication in influenza virus, reovirus, and human immunodeficiency virus infections. Further exploring this phenomenon, we found that addition of butyrate to cells deficient in type I interferon (IFN) signaling did not increase susceptibility to virus infection. Accordingly, we discovered that butyrate suppressed levels of specific IFN stimulated gene (ISG) products in human and mouse cells. Butyrate did not inhibit IFN-induced phosphorylation of transcription factors STAT1 and STAT2 or their translocation to the nucleus, indicating that IFN signaling was not disrupted. Rather, our data are suggestive of a role for inhibition of histone deacetylase activity by butyrate in limiting ISG induction. Global transcript analysis revealed that butyrate increases expression of more than 800 cellular genes, but represses IFN-induced expression of 60% of ISGs. Overall, we identify a new mechanism by which butyrate promotes virus infection via repression of ISGs. Our findings also add to the growing body of evidence showing that individual ISGs respond differently to type I IFN induction depending on the cellular environment, including the presence of butyrate. ImportanceButyrate is a lipid produced by intestinal bacteria that can regulate inflammation throughout the body. Here we show for the first time that butyrate influences the innate antiviral immune response mediated by type I IFNs. A majority of antiviral genes induced by type I IFNs were repressed in the presence of butyrate, resulting in increased virus infection and replication in cells. This suggests that butyrate could be broadly used as a tool to increase growth of virus stocks for research and for the generation of vaccines. Our research also indicates that metabolites produced by the gut microbiome can have complex effects on cellular physiology as demonstrated by the dampening of an inflammatory innate immune pathway by butyrate resulting in a pro-viral cellular environment.

microbiology↗

bioRxiv2020

Dynamics of mcr-1 prevalence and mcr-1-positive Escherichia coli after the cessation of colistin use as a feed additive for animals in China: a prospective cross-sectional and whole genome sequencing based molecular epidemiological study

BackgroundThe global dissemination of colistin resistance encoded by mcr-1 has been attributed to extensive use of colistin in livestock, threatening colistin efficacy in medicine. The emergence of mcr-1 in common pathogens, such as Escherichia coli, is of particular concern. Therefore, China banned the use of colistin in animal feed from May 1ST 2017. We investigated subsequent changes in mcr-1 prevalence, and the genomic epidemiology of mcr-1-positive Escherichia coli (MCRPEC). MethodsSampling was conducted pre- (October-December 2016) and post-colistin ban (October-December, 2017 and 2018, respectively). 3675 non-duplicate pig fecal samples were collected from 14 provinces (66 farms) in China to determine intervention-related changes in mcr-1 prevalence. 15193 samples were collected from pigs, healthy human volunteers, colonized and infected hospital inpatients, food and the environment in Guangzhou, to characterize source-specific mcr-1 prevalence and the wider ecological impact of the ban. From these samples, 688 MCRPEC were analyzed with whole genome sequencing (WGS), plasmid conjugation and S1-PFGE/Southern blots to characterize associated genomic changes. FindingsAfter the ban, mcr-1 prevalence decreased significantly in national pig farms, from 45{middle dot}0% (308/684 samples) in 2016, to 19{middle dot}4% (274/1416) in 2018 (p<0{middle dot}0001). This trend was mirrored in samples from most sources in Guangzhou (overall 19{middle dot}2% [959/5003 samples] in 2016; 5{middle dot}3% [238/4489] in 2018; p<0{middle dot}0001). The population structure of MCRPEC was diverse (23 sequence clusters [SCs]); ST10 clonal complex isolates were predominant (247/688 [36%]). MCRPEC causing infection in hospitalized inpatients were genetically more distinct and appeared less affected by the ban. mcr-1 was predominantly found on plasmids (632/688 [92%]). Common mcr-1 plasmid types included IncX4, IncI2 and IncHI2 (502/656 [76.5%]); significant increases in IncI2-associated mcr-1 and a distinct lineage of mcr-1-associated IncHI2 were observed post-ban. Changes in the frequency of mcr-1-associated flanking sequences (ISApl1-negative MCRPEC), 63 core genome SNPs and 30 accessory genes were also significantly different after the ban, consistent with rapid genetic adaptation in response to changing selection pressures. InterpretationA rapid, ecosystem-wide, decline in mcr-1 was observed after banning the use of colistin in animal feed, with associated genetic changes in MCRPEC. Genomic surveillance is key to assessing and monitoring stewardship interventions. FundingNational Natural Science Foundation of China

microbiology↗

bioRxiv2020

The ECF sigma factor PvdS regulates the type I-F CRISPR-Cas system in Pseudomonas aeruginosa.

During infection, successful colonization of bacteria requires a fine-tuned supply of iron acquired via iron transport systems. However, the transport systems serve as phage attachment sites and entry portals for foreign nucleic acid. Most bacteria possess the CRISPR-Cas system, which targets and destroys foreign nucleic acids and prevents deleterious effects of horizontal gene transfer. To understand the regulation of the CRISPR-Cas system, we performed genome-wide random transposon mutagenesis which led to the identification of the Extracytoplasmic Function (ECF) Sigma factor, PvdS as a regulator of the Type I-F CRISPR-Cas system in P. aeruginosa. We show that under iron-depleted conditions PvdS induces the expression of the type I-F CRISPR-Cas system. This regulatory mechanism involves direct interaction of PvdS with specific binding sites in the promoter region of cas1. Furthermore, activation of the CRISPR-Cas system under iron-depleted conditions increases horizontal gene transfer (HGT) interference and adaptation. The PvdS activation of the CRISPR-Cas system under iron limitation highlights the versatility of the P. aeruginosa in multitasking its regulatory machinery to integrate multiple stress factors. ImportanceP. aeruginosa infects a wide range of host organisms and adapts to various environmental stress factors such as iron limitation due to its elaborate regulatory system. P aeruginosa possesses the type I-F CRISPR-Cas system as a defense mechanism against phages infection and HGT. This work highlights the ability of P. aeruginosa to multitask its iron regulatory system to control the CRISPR-Cas system under a physiologically relevant stress factor such as iron limitation where the bacteria are vulnerable to phage infection. It also adds to the knowledge of the regulation of the CRISPR-Cas system in bacteria and presents a possible target that could prevent the emergence of phage resistance via the CRISPR-Cas system during the development of phage therapy.

microbiology↗

bioRxiv2020

IL4-driven microglia modulate stress resilience through BDNF-dependent neurogenesis

Adult neurogenesis in the dentate gyrus of the hippocampus is regulated by specific groups of microglia and is functionally implicated in behavioral responses to stress. However, the role of microglia in modulating hippocampal neurogenesis in stress responses remains poorly understood. Here we investigated the effects of IL4-driven Arg1+ microglia in the restoration of hippocampal neurogenesis and conferment of stress resilience. We found that low IL4 levels in the hippocampus of mice was associated with greater stress vulnerability and, conversely, overexpression of IL4 in the hippocampus induced a large number of Arg1+ microglia and ameliorated stress-induced depressive-like behaviors. Knockdown of microglial IL4 receptors in the hippocampus of mice exacerbated the stress-induced inflammatory response and abolished the antidepressant effects of IL4 overexpression. Enhancement or inhibition of IL4 signaling in hippocampal microglia modulated neurogenesis, and blockade of neurogenesis abolished the resilience to stress-induced depression. We further show that IL4-activated microglia is associated with upregulation of BDNF levels and neurogenesis. Taken together, our findings suggest that IL4-driven microglia in the hippocampus trigger BDNF-dependent neurogenesis in response to chronic stress, helping protect against depressive-like symptoms. These findings identify the modulation of a specific microglial phenotype as a treatment strategy for mood disorders. In BriefZhang et al. show that IL4-induced Arg1+ microglia restore hippocampal neurogenesis and promote resilience against stress in mice by increasing BDNF levels. Targeting microglia with immunomodulatory factors may be a strategy for treating mood disorders. HighlightsO_LIVulnerability to stress in mice is associated with reduced IL4 signaling in the hippocampus C_LIO_LIBrain-derived IL4 promotes adult hippocampal neurogenesis and stress resistance by driving Arg1+ microglia C_LIO_LIIL4-driven Arg1+ microglia enhance hippocampal neurogenesis via a BDNF-dependent pathway C_LI

neuroscience↗

bioRxiv2020

Modelling the epidemic trend of the 2019 novel coronavirus outbreak in China

We present a timely evaluation of the Chinese 2019-nCov epidemic in its initial phase, where 2019-nCov demonstrates comparable transmissibility but lower fatality rates than SARS and MERS. A quick diagnosis that leads to case isolation and integrated interventions will have a major impact on its future trend. Nevertheless, as China is facing its Spring Festival travel rush and the epidemic has spread beyond its borders, further investigation on its potential spatiotemporal transmission pattern and novel intervention strategies are warranted.

microbiology↗

bioRxiv2020

Alteration of fecal microbial compositions and bacterial taxa in female osteoporotic patients

BackgroundGut microbiota, mainly characterized by fecal bacterial compositions, affects human immune system and pathophysiological development. Our aim was to measure the quantitative differences of fecal bacterial compositions between osteoporotic patients and healthy subjects, and to identify novel bacterial taxa that speculate the incidence of osteoporosis in female. MethodWe recruited 104 female subjects, including 45 osteoporotic individuals and 59 healthy control. Fecal samples were collected for further analysis by 16S rRNA quantitative arrays and bioinformatics analysis. ResultsAnalyses of - and {beta}-diversity demonstrated that the diversity and composition of fecal bacterial compositions were both significant different in osteoporosis group, as compared with healthy group. Multiple bacterial genera were significantly increased (e.g., Roseburia and Bacteroides) or decreased (e.g., Streptococcus and Dorea) in the osteoporotic cases. Furthermore, the osteoporosiscould be efficiently determined by the random forest model based on differential taxa (area under ROC curve = 0.93). ConclusionThere were obvious different fecal microbial characteristics between female osteoporosis and healthy subjects. These findings provided evidence for understanding the host-gut microbiota interplay in female osteoporosis, and supported clinical applications of gut microbiota analysis for female osteoporosis diagnosis

microbiology↗

bioRxiv2020

Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential bat origin

Since the SARS outbreak 18 years ago, a large number of severe acute respiratory syndrome related coronaviruses (SARSr-CoV) have been discovered in their natural reservoir host, bats1-4. Previous studies indicated that some of those bat SARSr-CoVs have the potential to infect humans5-7. Here we report the identification and characterization of a novel coronavirus (nCoV-2019) which caused an epidemic of acute respiratory syndrome in humans, in Wuhan, China. The epidemic, started from December 12th, 2019, has caused 198 laboratory confirmed infections with three fatal cases by January 20th, 2020. Full-length genome sequences were obtained from five patients at the early stage of the outbreak. They are almost identical to each other and share 79.5% sequence identify to SARS-CoV. Furthermore, it was found that nCoV-2019 is 96% identical at the whole genome level to a bat coronavirus. The pairwise protein sequence analysis of seven conserved non-structural proteins show that this virus belongs to the species of SARSr-CoV. The nCoV-2019 virus was then isolated from the bronchoalveolar lavage fluid of a critically ill patient, which can be neutralized by sera from several patients. Importantly, we have confirmed that this novel CoV uses the same cell entry receptor, ACE2, as SARS-CoV.

microbiology↗

bioRxiv2020

Crystal structure of the giant panda MHC class I complex: first insights into the viral peptide presentation profile in the bear family

The viral cytotoxic T lymphocyte (CTL) epitope peptides presented by classical MHC-I molecules require the assembly of a peptide-MHC-I-{beta}2m (aka pMHC-I) trimolecular complex for TCR recognition, which is the critical activation link for triggering antiviral T cell immunity. Ursidae includes 5 genera and 8 species; however, research on T cell immunology in this family, especially structural immunology, is lacking. In this study, the structure of the key trimolecular complex pMHC-1 (aka pAime-128), which binds a peptide from canine distemper virus, was solved for the first time using giant panda as a representative species of Ursidae. The structural characteristics of the giant panda pMHC-I complex, including the unique pockets in the peptide-binding groove (PBG), were analyzed in detail. Comparing the panda pMHC-I to others in the bear family and extending the comparison to other mammals revealed distinct features. The interaction between MHC-I and {beta}2m, the features of pAime-128 involved in TCR docking and CD8 binding, the anchor sites in the PBG, and the CTL epitopes of potential viruses that infect pandas were concretely clarified. Unique features of pMHC-I viral antigen presentation in the panda were revealed by solving the three-dimensional structure of pAime-128. The distinct characteristics of pAime-128 indicate an unusual event that emerged during the evolution of the MHC system in the bear family. These results provide a new platform for research on panda CTL immunity and the design of vaccines for application in the bear family. IMPORTANCEUrsidae includes 5 genera and 8 species; however, the study of its immunology, especially structural immunology, is extremely rare to date. In this paper, we first crystallized the key complex pMHC-I, taking the giant panda as its representative species. Structural characteristics of the giant panda pMHC-I complexes, contains the unique pockets of PBG were analyzed in detail. Comparison of the panda pMHC-I in the bear family and other mammals, almost definite features was displayed. Meanwhile, the interaction between HC and LV, the unique features of pMHC-I in the CD8 binding and TCR docking, validation of anchor site in the PBG, and epitopes of potential viruses infected with the pandas, were concretely clarified. These unique characteristics of pMHC-I clearly indicate an unusual situation during the evolution of MHC molecules in the endangered pandas. These results also provide a novel platform for further study of panda T cell immunology and vaccines.

immunology↗

bioRxiv2020

Predicting transcription factor binding in single cells through deep learning

Characterizing genome-wide binding profiles of transcription factor (TF) is essential for understanding many biological processes. Although techniques have been developed to assess binding profiles within a population of cells, determining binding profiles at a single cell level remains elusive. Here we report scFAN (Single Cell Factor Analysis Network), a deep learning model that predicts genome-wide TF binding profiles in individual cells. scFAN is pre-trained on genome-wide bulk ATAC-seq, DNA sequence and ChIP-seq data, and utilizes single-cell ATAC-seq to predict TF binding in individual cells. We demonstrate the efficacy of scFAN by studying sequence motifs enriched within predicted binding peaks and investigating the effectiveness of predicted TF peaks for discovering cell types. We develop a new metric "TF activity score" to characterize each cell, and show that the activity scores can reliably capture cell identities. The method allows us to discover and study cellular identities and heterogeneity based on chromatin accessibility profiles.

bioinformatics↗

bioRxiv2020

The Nonequilibrium Mechanism of Noise Enhancer synergizing with Activator in HIV Latency Reactivation

Reactivating HIV latency and then simultaneously eliminating it by antiretroviral therapy has become a leading strategy in curing HIV. Recently, single-cell screening experiments have shown the drug synergy between two categories of biomolecules, Activators (AC) and Noise Enhancers (NE): NE can amplify the reactivation of latent HIV induced by AC, although NE itself cannot reactivate HIV latency. Based on an established LTR-two-state effective model, we uncover two necessary conditions for this type of drug synergy: The decreasing of the turning-on rate of LTR induced by NE is highly inhibited when presented with AC; The timescale of LTR turning off without AC/NE presented should be no slower than the timescale of Tat transactivation. Then we propose a detailed LTR-four-state mechanistic model with both AC/NE regulation kinetics and Tat transactivation circuit. We show that, in order to achieve drug synergy, the system of HIV gene state transition must operate out of thermodynamic equilibrium, which is caused by energy input. The direction of energy input determines whether the inhibition of NE upon the reactivation rate of LTR-off states (unbinding of RNAP) can be successfully prevented in the presence of AC. The drug synergy can also be significantly enhanced if the energy input is appropriately distributed to more than one reaction. Our model reveals a generic nonequilibrium mechanism underpinning the noise enhanced drug synergy, which may apply to identify the same drug synergy on reactivating a diverse class of lentivirus latency. Significance StatementThe "kick and kill" strategy has become a promising way to cure HIV by eliminating latent HIV reservoirs, the main barrier to a clinical cure. Two categories of biomolecules, Activators (AC) and Noise Enhancers (NE), have been found to have synergy on reactivating latent HIV (kick strategy). We uncover the underlying non-equilibrium mechanism of such drug synergy by developing mathematical models based on genetic regulatory kinetics. We find that controlling the magnitude and direction of energy input into genetic regulatory kinetics can prevent NE from reducing the turn-on rate of the inactivated gene state in the presence of AC, which produces the synergy. This general nonequilibrium mechanism can be useful for identifying other drug synergies on lentivirus latency reactivation.

systems biology↗

bioRxiv2020

Domain segregated 3D chromatin structure and segmented DNA methylation in carcinogenesis

The three-dimensional (3D) chromatin structure, together with DNA methylation and other epigenetic marks, profoundly affects gene expression and displays abnormal behaviors in cancer cells. We elucidated the chromatin architecture remodeling in carcinogenesis from the perspective of spatial interactions between CGI forest and prairie domains, which are two types of megabase-sized domains defined by different sequence features but show distinct epigenetic and transcriptional patterns. DNA sequence strongly affects chromosome spatial interaction, DNA methylation and gene expression. Globally, forests and prairies show enhanced spatial segregation in cancer cells and such structural changes are accordant with the alteration of CGI interactions and domain boundary insulation, which could affect vital cancer-related properties. As the cancer progresses, a gradual increase of the DNA methylation difference between the two types of DNA domains is also observed for many different types of cancers. These observations are consistent with the change of transcriptional level differences of genes in these two domains, suggesting a highly-connected global structural, epigenetic and transcriptional activity changes in carcinogenesis.

cancer biology↗

bioRxiv2020

mTORC2 mediate FLCN-induced HIF2α nuclear import and proliferation of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC), as the most important type of renal carcinoma, has a high incidence and easy metastasis. Folliculin (FLCN) was identified as a tumor suppressor gene. Its deletions and mutations are associated with a potential risk of kidney cancer. At present, the specific molecular mechanism of FLCN-induced proliferation, invasion and migration in clear cell renal cell carcinoma remains elusive. In this study, we demonstrated that FLCN controled cell proliferation, invasion and migration through PI3K/mTORC2 pathway. FLCN combined with HIF2 in various normal and cancerous renal cells, and mTORC2 mediate FLCN effectively alleviated the deterioration of renal cancer cells by degrading HIF2. Silencing of FLCN showed promotion of HIF2 protein expression, which in turn led to an increase in downstream target genes Cyclin D1 and MMP9. Moreover, when interfering with siFLCN, HIF2 degradation rate was delayed, and the time of entry into the nucleus was advanced. Taken together, our study illustrated that mTORC2 promoted the specific molecular mechanism of HIF2 by down-regulated FLCN, and might be a new therapeutic target against renal cancer progression.

cell biology↗

bioRxiv2020

1--4-phenylpiperazine Treatment After Brain Irradiation Preserves Cognitive Function in Mice

BackgroundNormal tissue toxicity to the CNS is an inevitable consequence of a successful radiotherapy of brain tumors or cancer metastases to the CNS. Cranial irradiation commonly leads to neurocognitive deficits that manifest months or years after treatment. Mechanistically, radiation-induced loss of neural stem/progenitor cells, neuro-inflammation and de-myelinization are contributing factors that lead to progressive cognitive decline. MethodsThe effects of Compound #5 on irradiated murine neurospheres, microglia cells and patients-derived gliomaspheres were assessed in sphere-formation assays, flow cytometry and IL-6 ELISAs, Activation of the Hedgehog pathway was studied by qRT-PCR. The in vivo effects of Compound #5 were analyzed using flow cytometry, sphere-formation assays, immune-histochemistry, behavioral testing and an intracranial mouse model of glioblastoma. ResultsWe report that 1-[(4-Nitrophenyl)sulfonyl]-4-phenylpiperazine (Compound #5) mitigates radiation-induced normal tissue toxicity in the brains of mice. Compound #5 treatment significantly increased the number of neural stem/progenitor cells after brain irradiation in female animals, inhibited radiation-induced microglia activation and expression of the pro-inflammatory cytokine interleukin-6. Behavioral testing revealed that treatment with Compound #5 after radiotherapy successfully mitigates radiation-induced decline in motor, sensory and memory function of the brain. In mouse models of glioblastoma, Compound #5 showed no toxicity and did not interfere with the growth-delaying effects of radiation. ConclusionsWe conclude that Compound #5 has the potential to mitigate cognitive decline in patients undergoing partial or whole brain irradiation without promoting tumor growth and that the use of this compound as a radiation mitigator of radiation late effects on the CNS warrants further investigation. Importance of the StudySuccessful radiotherapy of CNS malignancies inevitably lead to cognitive decline in cancer survivors and treatment options to mitigate this side effect are limited. We present evidence that a piperazine compound can prevent cognitive decline in mice after total brain irradiation without compromising the antitumor effect of radiation, suggesting that this compound could be used to mitigate radiation side effects in brain tumor patients undergoing radiotherapy.

neuroscience↗