Biology subjects

Chen, C. C.

Publications and source records attributed to Chen, C. C..

At least 19 recordsLinked to original sources

bioRxiv2026

Efficacy of Tumor Treating Fields (TTFields) in triple negative breast cancer cells and synergy with PARP inhibitor talazoparib

Breast cancer is the most diagnosed cancer worldwide. Triple-negative breast cancer (TNBC) is a subtype with a poor prognosis because of its aggressiveness and high likelihood of relapse, making its treatment particularly challenging. We explored the effect of Tumor Treating Fields (TTFields) as a novel treatment option for breast cancer, which can be used together with other therapies, such as PARP inhibitors. TTFields use alternating electric fields to inhibit cell growth and induce cellular damage. Our findings indicate that TTFields increase expression of the universal cell cycle CDK inhibitory protein p21(WAF1)/CDKN1A independently of TP53 mutational status. Moreover, when used together with the PARP inhibitor talazoparib, the combination further upregulates p21 protein. Both TTFields alone and together with talazoparib induce cell death as documented by PARP cleavage while reducing markers of cell growth and anti-apoptotic proteins, including p-STAT3, STAT3, and MCL-1. Additionally, TTFields together with talazoparib induce DNA damage, as indicated by increased {gamma}H2AX expression. The combination of talazoparib plus TTFields treatment decrease PDL-1 levels and given its utility in predicting response to PD-1/PD-L1 by mediating immune evasion, this raises the possibility of future combination for immune modulation in cancer therapy. Our preclinical results suggest TTFields alone or together with PARP inhibitors such as talazoparib as a promising therapeutic approach for further development for the treatment of breast cancer.

cancer biology↗

bioRxiv2026

A miniature bioluminescent platform for imaging structured RNAs

A broader understanding of RNA biology requires methods for visualizing transcript dynamics in native environments. Common imaging approaches rely on fluorescent probes that require excitation light and often depend on large aptamer arrays, limiting sensitivity and compatibility with many non-coding RNAs, particularly highly structured folds. To address these challenges, we developed a miniaturized bioluminescent platform for RNA imaging. This system employs a compact RNA tag that assembles luciferase fragments upon binding of monomeric RNA-binding proteins (RNA lanterns). Systematic optimization of the RNA component yielded a structured 24-nucleotide tag, representing greater than 3-fold reduction in size relative to the original C-11-B RNA tag, placing it among the smallest RNA imaging tags reported to date. The optimized tag enabled RNA-dependent bioluminescence detection in live cells, notably as a small, single insert within highly structured non-coding RNAs, including the MALAT1 ENE domain and a small HDV-like ribozyme. Collectively, this work establishes a miniaturized bioluminescent platform for imaging a broad range of RNA targets in living systems.

molecular biology↗

bioRxiv2026

A SRC-Annexin A2 axis that couples membrane repair to microRNA export during radiation stress in glioblastoma

Repair of ionizing-radiation (IR)-induced membrane damage is essential for cell survival, and Annexin A2 (ANXA2) mediates this repair by promoting shedding of microvesicles containing both damaged lipid and ANXA2. Here, we show that coupling this process to microRNA export contributes to radiation resistance of glioblastoma, the most common adult brain cancer. Structural modeling and mutational analysis identify that ANXA2 tyrosine 23 (Y23) phosphorylation, required for its IR-induced localization to damaged membranes, is also essential for binding miR-603, a critical regulator of glioblastoma cell state. This binding is required for IR-induced miR-603 export, indicating that the repair program recruiting ANXA2 also positions it to load miR-603 into microvesicles. Mutations that abolish ROS-induced sulfenylation and activation of SRC (SRC-C185A/C245A) suppressed ANXA2-Y23 phosphorylation, microvesicle shedding, and miR-603 export. The epistatic interaction between ANXA2-Y23A, SRC-C185A/C245A, and miR-603 delineates a therapeutically targetable radiation-response network that couples membrane repair with miRNA export.

cancer biology↗

bioRxiv2025

H3.3 De Novo Mutations Alter Lysine 36 Methylation via Distinct Mechanisms

Bryant-Li-Bhoj syndrome (BLBS) is caused by de novo mutations on histone H3.3 and is generally characterized by severe neurodevelopmental deficits. Oncogenic H3.3 amino acid substitutions were described over the past decade, but the molecular impact of BLBS mutations remained unstudied. The remarkable number and spread of the missense mutations led us to hypothesize that some converge on the same downstream effectors. We recently showed that H3.3G34R/V substitutions, seen in both cancer and BLBS, impair associations with the DNMT3A DNA methyltransferase. Our proteomic, enzymatic, and structural analyses now show that H3.3 BLBS mutations flanking glycine 34 have surprisingly stark effects on H3K36 methyltransferases, drastically altering H3K36 methyl states in cis and the binding of effector proteins with a PWWP domain, including DNMT3A/B. That confirms the existence of molecular commonalities amongst BLBS H3.3 point mutants while providing some of the first mechanistic insights into the syndrome.

molecular biology↗

bioRxiv2025

Enabling CAR-T Cell Immunotherapy in Glioblastoma by Modifying Tumor Microenvironment via Oncolytic Adenovirus Encoding Bispecific T Cell Engager

Recent clinical trials show that CAR-T cell therapies can initially blunt tumor growth in glioblastoma (GBM) patients. However, the tumor microenvironment activates mechanisms that inhibit tumor-killing potential of the CAR-T cells and limit their therapeutic efficacy. To counteract this, we have utilized oncolytic adenovirus (OV) Ad5-{Delta}24-RGD as a platform to overexpress a bispecific T cell engager (BiTE) targeting both T cell marker CD3 and GBM specific tumor associated antigen IL-13R2. We first demonstrated that OV-BiTE could enhance recruitment of T cells to GBM in vitro and in vivo. We then showed that intratumoral injection of OV-BiTE followed by infusion of combined EGFR- and EGFRvIII-CAR-T cells was more effective than OV-BiTE supplemented with either CAR-T therapy alone, and led to significant tumor eradication in a GBM xenograft mouse model. In conclusion, our multimodal OV-BiTE & CAR-T cell immunotherapy is capable of overcoming immunosuppressive tumor microenvironment and GBM resistance to treatment. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=160 SRC="FIGDIR/small/667708v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@c55b15org.highwire.dtl.DTLVardef@deffb2org.highwire.dtl.DTLVardef@64ff90org.highwire.dtl.DTLVardef@c65fc2_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIOncolytic adenovirus encoding bispecific T cell engager (OV-BiTE) combines two immunotherapeutic agents into one. C_LIO_LIOV-BiTE strategy modifies tumor microenvironment and enhances recruitment of T cells to glioblastoma (GBM) in vitro and in vivo. C_LIO_LIMultimodal OV-BiTE & CAR-T cell immunotherapy effectively reduced tumor mass in a GBM xenograft mouse model and is superior to either immunotherapy alone. C_LI

cancer biology↗

bioRxiv2025

Concerted actions of distinct serotonin neurons orchestrate female pup care behavior

In many mammalian species, female behavior towards infant conspecifics changes across reproductive stages. Sexually naive females interact minimally or aggressively with infants, whereas the same animals exhibit extensive care behavior, even towards unrelated infants, after parturition1-6. Here, we discovered that two distinct sets of serotonin neurons collectively mediate this dramatic transition in maternal behavior--serotonin neurons projecting to the medial preoptic area (mPOA) promote pup care in mothers, whereas those projecting to the bed nucleus of the stria terminalis (BNST) suppress pup interaction in virgin female mice. Disrupting serotonin synthesis in either of these subpopulations or stimulating either subpopulation is sufficient to toggle pup-directed behavior between that displayed by virgin females and that of lactating mothers. In virgin female mice, the first pup interaction triggers an increase in serotonin release in BNST but a decrease in mPOA. In mothers, serotonin activity becomes greatly elevated in mPOA during pup interactions. Acute interruption of serotonin signaling locally in either mPOA or BNST disrupts the stage-dependent switch in pup care. Together, these results highlight how functionally distinct serotonin subpopulations orchestrate social behaviors appropriate for a given reproductive state, and suggest a circuit logic for how a neuromodulator coordinates adaptive behavioral changes across life stages.

neuroscience↗

bioRxiv2025

Modulating populational variance of methyl-guanine methyl transferase expression through miR-181d degradation: a novel mechanism of temozolomide resistance

Intratumoral heterogeneity plays a pivotal role in cancer evolution, providing the substrate for adaptation to selective pressures, including treatment with chemotherapy. Here, we show that micro-RNA regulation of variance in the expression of the DNA repair protein methyl-guanine methyl transferase (MGMT) contributes to this heterogeneity and acquired therapeutic resistance. In cell lines derived from glioblastomas, the most common form of primary brain tumor, treatment with standard-of-care temozolomide chemotherapy triggers a feed-forward loop between polyribonucleotide nucleotidyltransferase 1 (PNPT1) and miR-181d, an MGMT regulating miRNA, expediting miR-181d degradation. This degradation requires the activation of Ataxia Telangiectasia and Rad3-related (ATR) kinase. The degradation of miR-181d in glioblastoma cells increased both the mean and the variance of MGMT expression in the cell population. Subclone reconstituted cell populations with similar populational mean MGMT levels but with differences in the variance of MGMT expression exhibited differential temozolomide sensitivity, with the higher MGMT variance population showing increased resistance. This resistance is suppressed by exogenously transfected miR-181d. These findings suggest a key role for miRNA in regulating intra-tumoral heterogeneity through modulation of key DNA repair enzymes and provide a compelling rationale for miRNA delivery as a platform for glioblastoma therapy. Significance StatementThis study demonstrates a mechanistic link between a feed-forward loop mediating microRNA degradation and cell-to-cell variance in gene expression, and the contribution of this mechanism to intratumoral heterogeneity and therapeutic resistance. We show that when glioblastoma, the most common form of adult primary brain tumor, is treated with standard-of-care chemotherapy, temozolomide, a feed-forward loop between miR-181d and PNPT1 is initiated, causing rapid degradation of miR-181d. This degradation increases the cell-to-cell variability in methyl-guanine methyl transferase (MGMT) expression, expanding intra-tumoral heterogeneity and contributing to acquired temozolomide resistance. This process can be suppressed by therapeutic delivery of microRNA, providing compelling considerations for clinical translation.

cancer biology↗

bioRxiv2025

UHRF1 is critical for tumor-promoting inflammation and tumorigenesis in retinoblastoma

Retinoblastoma, the most common pediatric intraocular malignancy, arises from RB1 inactivation, leading to uncontrolled proliferation of retinal progenitor cells. Epigenetic dysregulation a key driver of retinoblastoma progression, yet the underlying mechanisms are poorly understood. UHRF1, a regulator of DNA methylation and chromatin remodeling, has been implicated in oncogenesis but its role in retinoblastoma has not been fully characterized. To investigate Uhrf1s role in tumor initiation and progression, we generated a genetically engineered mouse model of retinoblastoma with conditional Uhrf1 knockout. Remarkably, Uhrf1 loss completely blocked tumor formation, despite persistent early oncogenic events. Transcriptomic and epigenomic profiling revealed that Uhrf1 is essential for tumor progression, facilitating oncogenic transcription, chromatin accessibility, and aberrant DNA methylation. Beyond its epigenetic role, we found Uhrf1 modulates the tumor immune microenvironment, promoting chemokine secretion and microglial infiltration, suggesting that Uhrf1 promotes immune cell recruitment. Mechanistically, Uhrf1 enhances chemokine expression through NF-{kappa}B signaling, establishing a novel connection between epigenetic regulation and tumor-associated immune responses. These findings establish Uhrf1 as a critical driver of retinoblastoma progression, essential for tumor maintenance but not initiation. By sustaining oncogenic transcriptional programs and shaping a pro-tumor immune microenvironment, Uhrf1 emerges as a promising therapeutic target for inhibiting tumor growth and immune evasion.

cancer biology↗

bioRxiv2025

USP7 inhibition perturbs proteostasis and tumorigenesis in triple negative breast cancer

The deubiquitinase USP7 is a critical regulator of tumorigenesis, known for stabilizing the MDM2-p53 pathway. Emerging evidence highlights USP7s p53-independent roles in proliferation and tumorigenesis. Triple negative breast cancers frequently inactivate p53 and this disease subtype remains difficult to treat and in need of new therapeutic options. Our study reveals that USP7 is upregulated in TNBC patient tumors. Importantly, genetic and pharmacologic USP7 inactivation impaired tumor progression in TNBC models. To explore USP7s role in p53-mutant TNBCs, we performed deep quantitative proteomics across TNBC cell lines, identifying shared USP7 targets involved in cell proliferation, genome stability, and proteostasis. Acute USP7 inactivation allowed us to infer proximally controlled proteins which are likely direct targets. Surprisingly, many of the proteins downregulated by USP7 inhibition are E3 ubiquitin ligases. Thus, a key USP7 function in TNBC is to antagonize the degradation of ubiquitinating enzymes, since these enzymes are often susceptible to auto-ubiquitination and degradation. Notably, we identified TOPORS, a dual ubiquitin- and SUMO-ligase, among novel USP7 substrates. TOPORS interacts with the BRCA1-A DNA damage repair complex suggesting a USP7-TOPORS-BRAC1-A axis that might further explain the continued proliferation of genomically unstable TNBCs. Collectively, these data nominate USP7 as a potential therapeutic in TNBC.

cancer biology↗

bioRxiv2024

A High-Throughput Platform for Assessing Single Fly Learning and Memory: Individual Drosophila Olfactory Conditioner (iDOC)

Olfactory conditioning in Drosophila melanogaster is a widely used behavioral paradigm for uncovering the neural basis of learning and memory. The traditional T-maze assay, however, relies on group-level assessments and cannot examine individual flies learning and memory abilities. To address this limitation, we developed the Individual Drosophila Olfactory Conditioner (iDOC), an apparatus for single-fly conditioning and memory assessment. Using iDOC, we demonstrated aversive olfactory learning, short-term memory (STM), anesthesia-resistant memory (ARM), and protein synthesis-dependent long-term memory (LTM) in individual flies, consistent with previous experiments conducted using the T-maze. As an individual memory assessment method, iDOC can be integrated with other behavioral assays at the single animal level, such as sleep monitoring. Notably, we found that spaced training, which induces LTM, also promotes post-learning sleep, while massed training, which induces ARM, did not. iDOC thus provides a powerful platform for investigating learning and memory and its interplay with other behavioral processes at the individual animal level. HighlightsO_LIDeveloped iDOC for high-throughput, single-fly aversive olfactory training and memory assessment C_LIO_LIDemonstrated aversive learning, STM, ARM, and LTM in individual flies using iDOC C_LIO_LISpaced conditioning, and not massed conditioning, promotes sleep C_LI

animal behavior and cognition↗

bioRxiv2024

Combination of Imipridone ONC201 or ONC206 with Temozolomide and Radiotherapy in triple ITR therapy reduces intracranial tumor burden and prolongs survival in an orthotopic wild-type IDH GBM mouse model

Glioblastoma remains the most lethal common primary brain tumor in adults with limited therapeutic options. TIC10/ONC201, a first-in-class imipridone we discovered, achieved meaningful therapeutic effects in phase I/II trials in patients with diffuse gliomas harboring H3K27M mutations, and currently the drug is in randomized phase III testing (ACTION trial; NCT05580562). ONC201 targets mitochondrial protease ClpP to disrupt oxidative phosphorylation and trigger the integrated stress response (ISR), TRAIL/DR5, and tumor cell death. We hypothesized that ONC201 and its analogue ONC206 synergize with temozolomide (TMZ) and ionizing radiation (IR), standard-of-care glioblastoma therapies. ONC201 enhances TMZ or IR-induced apoptosis, and cytotoxicity. ClpP-silencing suppresses ONC201-induced cytotoxicity but not TMZ or RT. Both ONC201 and ONC206 reduce expression of TMZ-resistance mediator MGMT. Suppression of MGMT protein was observed in H3K27M-mutated DIPG cell lines following treatment with ONC201 or ONC206 with or without TMZ. Cytokine profiling indicates distinct ONC201 alterations relative to TMZ suggesting distinct anti-tumor immune mechanisms. Triple IR+TMZ+ONC201 (ITR) therapy prolongs median survival to 123 days with a tail on survival curve (3-of-7 mice alive beyond 200-days) in an orthotopic U251 GBM model versus ONC201 (44-days; p=0.000197), IR (63-days; p=0.0012), TMZ (78-days; p=0.0354), ONC201+IR (55-days; p=0.0004), ONC201+TMZ (80-days; p=0.0041) and IR+TMZ (103-days; p>0.05). By 231-days, the only surviving mice were in IRT group. Our results support investigation of ONC201/ONC206 in combination with TMZ and IR (ITR) in GBM or H3K27M mutated diffuse glioma therapy.

cancer biology↗

bioRxiv2024

The inactive X chromosome drives sex differences in microglial inflammatory activity in human glioblastoma

Whether an individual is a biological female or male affects cancer risk, but the responsible mechanisms and cell types remain obscure. Glioblastoma multiforme (GBM) is a male-biased cancer that is highly aggressive, and resistant to treatment, with poor patient survival. Dismal prognoses in GBM are due in part to the specialized immune system of the brain, consisting largely of microglia, which regulate GBM development and progression. We hypothesized that microglia function differently in females and males and thereby contribute to the observed male bias in GBM. We sorted TAM-MGs (tumor-associated macrophages - microglia) from human GBMs and low-grade gliomas and performed bulk transcriptomic and epigenomic assays to identify sex-biased gene expression. We used published single-cell transcriptomic data from human GBMs to predict sex-biased TAM-MG interactions with other cell types. We found that female and male TAM-MGs mount different inflammatory responses, with female TAM-MGs displaying stronger interferon signaling and cytotoxic T-cell interactions that should enhance anti-tumor immunity in GBM. We validated these sex-differential inflammatory responses experimentally, and determined that genes on the sex chromosomes, specifically those expressed by Xi (the "inactive" X chromosome), drive these differences. Together, our results suggest that sex-differential TAM-MG inflammatory responses contribute to the higher incidence and mortality of GBM in males.

genomics↗

bioRxiv2024

Droplet Hi-C for Fast and Scalable Profiling of Chromatin Architecture in Single Cells

Comprehensive analysis of chromatin architecture is crucial for understanding the gene regulatory programs during development and in disease pathogenesis, yet current methods often inadequately address the unique challenges presented by analysis of heterogeneous tissue samples. Here, we introduce Droplet Hi-C, which employs a commercial microfluidic device for high-throughput, single-cell chromatin conformation profiling in droplets. Using Droplet Hi-C, we mapped the chromatin architecture at single-cell resolution from the mouse cortex and analyzed gene regulatory programs in major cortical cell types. Additionally, we used this technique to detect copy number variation (CNV), structural variations (SVs) and extrachromosomal DNA (ecDNA) in cancer cells, revealing clonal dynamics and other oncogenic events during treatment. We further refined this technique to allow for joint profiling of chromatin architecture and transcriptome in single cells, facilitating a more comprehensive exploration of the links between chromatin architecture and gene expression in both normal tissues and tumors. Thus, Droplet Hi-C not only addresses critical gaps in chromatin analysis of heterogeneous tissues but also emerges as a versatile tool enhancing our understanding of gene regulation in health and disease.

genomics↗

bioRxiv2023

Inhibition of CPEB3 ribozyme elevates CPEB3 protein expression and polyadenylation of its target mRNAs, and enhances object location memory

A self-cleaving ribozyme that maps to an intron of the cytoplasmic polyadenylation element binding protein 3 (CPEB3) gene is thought to play a role in human episodic memory, but the underlying mechanisms mediating this effect are not known. We tested the activity of the murine sequence and found that the ribozymes self-scission half-life matches the time it takes an RNA polymerase to reach the immediate downstream exon, suggesting that the ribozyme-dependent intron cleavage is tuned to co-transcriptional splicing of the CPEB3 mRNA. Our studies also reveal that the murine ribozyme modulates maturation of its harboring mRNA in both cultured cortical neurons and the hippocampus: inhibition of the ribozyme using an antisense oligonucleotide leads to increased CPEB3 protein expression, which enhances polyadenylation and translation of localized plasticity-related target mRNAs, and subsequently strengthens hippocampal-dependent long-term memory. These findings reveal a previously unknown role for self-cleaving ribozyme activity in regulating experience-induced co-transcriptional and local translational processes required for learning and memory. Significance StatementCytoplasmic polyadenylation-induced translation is one of the key steps for regulating protein synthesis and neuroplasticity in the hippocampus. The CPEB3 ribozyme is a highly conserved mammalian self-cleaving catalytic RNA with unknown biological roles. In this study, we investigated how the intronic ribozyme affects the CPEB3 mRNA maturation and translation, and its subsequent effect on memory formation. Our findings show that the ribozyme activity is anti-correlated with CPEB3 mRNA splicing: inhibition of the ribozyme results in higher mRNA and protein levels, which contribute to long-term memory. Our studies offer new insights into the role of the CPEB3 ribozyme in neuronal translational control for the activity-dependent synaptic functions that underlie long-term memory and demonstrate a novel biological role for self-cleaving ribozymes.

neuroscience↗

bioRxiv2023

Cooperativity between H3.3K27M and PDGFRA poses multiple therapeutic vulnerabilities in human iPSC-derived diffuse midline glioma avatars

Diffuse midline glioma (DMG) is a leading cause of brain tumor death in children. In addition to hallmark H3.3K27M mutations, significant subsets also harbor alterations of other genes, such as TP53 and PDGFRA. Despite the prevalence of H3.3K27M, the results of clinical trials in DMG have been mixed, possibly due to the lack of models recapitulating its genetic heterogeneity. To address this gap, we developed human iPSC-derived tumor models harboring TP53R248Q with or without heterozygous H3.3K27M and/or PDGFRAD842V overexpression. The combination of H3.3K27M and PDGFRAD842V resulted in more proliferative tumors when gene-edited neural progenitor (NP) cells were implanted into mouse brains compared to NP with either mutation alone. Transcriptomic comparison of tumors and their NP cells of origin identified conserved JAK/STAT pathway activation across genotypes as characteristic of malignant transformation. Conversely, integrated genome-wide epigenomic and transcriptomic analyses, as well as rational pharmacologic inhibition, revealed targetable vulnerabilities unique to the TP53R248Q; H3.3K27M; PDGFRAD842V tumors and related to their aggressive growth phenotype. These include AREG-mediated cell cycle control, altered metabolism, and vulnerability to combination ONC201/trametinib treatment. Taken together, these data suggest that cooperation between H3.3K27M and PDGFRA influences tumor biology, underscoring the need for better molecular stratification in DMG clinical trials.

genomics↗

bioRxiv2023

Cell migration simulator-based biomarkers for glioblastoma

Glioblastoma is the most aggressive malignant brain tumor with poor survival due to its invasive nature driven by cell migration, with unclear linkage to transcriptomic information. Here, we applied a physics-based motor-clutch model, a cell migration simulator (CMS), to parameterize the migration of glioblastoma cells and define physical biomarkers on a patient-by-patient basis. We reduced the 11-dimensional parameter space of the CMS into 3D to identify three principal physical parameters that govern cell migration: motor number - describing myosin II activity, clutch number - describing adhesion level, and F-actin polymerization rate. Experimentally, we found that glioblastoma patient-derived (xenograft) (PD(X)) cell lines across mesenchymal (MES), proneural (PN), classical (CL) subtypes and two institutions (N=13 patients) had optimal motility and traction force on stiffnesses around 9.3kPa, with otherwise heterogeneous and uncorrelated motility, traction, and F-actin flow. By contrast, with the CMS parameterization, we found glioblastoma cells consistently had balanced motor/clutch ratios to enable effective migration, and that MES cells had higher actin polymerization rates resulting in higher motility. The CMS also predicted differential sensitivity to cytoskeletal drugs between patients. Finally, we identified 11 genes that correlated with the physical parameters, suggesting that transcriptomic data alone could potentially predict the mechanics and speed of glioblastoma cell migration. Overall, we describe a general physics-based framework for parameterizing individual glioblastoma patients and connecting to clinical transcriptomic data, that can potentially be used to develop patient-specific anti-migratory therapeutic strategies generally. Significance StatementSuccessful precision medicine requires biomarkers to define patient states and identify personalized treatments. While biomarkers are generally based on expression levels of protein and/or RNA, we ultimately seek to alter fundamental cell behaviors such as cell migration, which drives tumor invasion and metastasis. Our study defines a new approach for using biophysics-based models to define mechanical biomarkers that can be used to identify patient-specific anti-migratory therapeutic strategies.

bioengineering↗

bioRxiv2022

Wide-field Calcium Imaging Reveals Widespread Changes in Cortical Connectivity Following Repetitive, Mild Traumatic Brain Injury in the Mouse

The physiologic basis underlying the long-term consequences of repetitive, mild traumatic brain injury (mTBI) remains poorly understood. Mild traumatic brain injury often results in brief loss of consciousness, impaired attention and concentration, memory problems, impulsivity, and headache, without objective findings on clinical imaging or examination. The effects of mTBI can persist and become cumulative with repetitive injury, suggesting global alterations in cortical networks. Using transparent polymer skulls, we performed mesoscopic Ca2+ imaging in mice to evaluate how repetitive mTBI alters patterns of neuronal interactions across the dorsal cerebral cortex. Spatial Independent Component Analysis (sICA) and Localized semi-Nonnegative Matrix Factorization (LocaNMF) were used to quantify changes in cerebral functional connectivity (FC). Repetitive, mild, controlled cortical impacts induce temporary neuroinflammatory responses, characterized by increased density of microglia exhibiting de-ramified morphology. These temporary neuro-inflammatory changes were not associated with compromised cognitive performance in the Barnes maze or motor function as assessed by rotarod. However, long-term alterations in functional connectivity were observed. Widespread, bilateral changes in FC occurred immediately following impact and persisted for up to 7 weeks, the duration of the experiment. Network alterations include decreases in global efficiency, clustering coefficient, and nodal strength, thereby disrupting functional interactions and information flow throughout the dorsal cerebral cortex. A subnetwork analysis shows the largest disruptions in FC were concentrated near the impact site. Therefore, repetitive mTBI induces a transient neuroinflammation, without alterations in cognitive or motor behavior, and a reorganized cortical network evidenced by the widespread, chronic alterations in cortical FC. Significance StatementMore than 2.5 million individuals in the United States suffer minor traumatic brain injuries annually. Because these injuries are typically not associated with visible anatomic injuries or objective clinical findings, they were thought benign and fully recoverable. However, there is increasing awareness of the long-term deleterious consequences, particularly in patients who suffer repeated mTBI. Using long-term, mesoscopic neuronal Ca2+ imaging to characterize the dorsal cerebral cortical connectome following repetitive mTBI, we show extensive, persistent changes in functional connectivity, not only at the site of injury but throughout the cortex. These findings provide new insights into the pathophysiology of mTBI.

neuroscience↗

bioRxiv2021

Therapeutic activation of virus-specific resident memory T cells within the glioblastoma microenvironment

Glioblastoma multiforme (GBM) is among the most aggressive, treatment resistant cancers, and despite standard of care surgery, radiation and chemotherapy, is invariably fatal. GBM is marked by local and systemic immunosuppression, contributing to resistance to existing immunotherapies that have had success in other tumor types. Memory T cells specific for previous infections reside in tissues throughout the host and these tissue resident memory T cells (TRM) are capable of rapid and potent immune activation. Here, we show that virus-specific memory CD8+ T cells expressing tissue resident markers populate the mouse and human glioblastoma microenvironment. Reactivating virus-specific TRM through intra-tumoral delivery of adjuvant-free virus-derived peptide triggered local immune activation. This delivery translated to anti-neoplastic effects, which improved survival in a murine glioblastoma model. Our results indicate that virus-specific TRM are a significant part of the glioblastoma immune microenvironment and can be leveraged to promote anti-tumoral immunity.

immunology↗