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Cai, C.

Publications and source records attributed to Cai, C..

At least 37 records · Page 2Linked to original sources

Unlocking biological insight from single-cell data with an interpretable dual-stream foundation model

Deep learning foundation models are revolutionizing single-cell biology, yet learning holistic and discriminative representations from complex, high-dimensional data remains a central challenge. Although Transformer-based single-cell language models have shown significant progress, they typically rely on a single input-encoding scheme, a practice that results in the loss of critical gene expression information and hinders the effective learning of global cellular representations. To address these challenges, we introduce scDMC, an innovative single-cell Dual-stream Masked Contrastive pre-training framework designed to synergistically optimize information fidelity at both the gene and cellular levels. Pre-trained on only 2 million cells far fewer than the datasets used by mainstream models, scDMC sets a new state-of-the-art in multiple benchmark tasks, including cell annotation, clustering, and data integration. More importantly, we demonstrate that scDMC can uncover functional gene modules, infer cell-type-specific regulatory networks in a data-driven manner, and exhibits a high degree of biological interpretability.

bioinformatics↗

Serratia marcescens Outer Membrane Vesicles rapidly paralyze Drosophila melanogaster through triggering apoptosis in the nervous system

The pathogenicity of Gram-negative bacteria is mediated by multiple virulence factors that likely include secreted Outer Membrane Vesicles (OMVs) that can act as a cargo for delivery of enzymes or toxins to target tissues. Here, we have studied the effects on the host of OMVs prepared from one of the most potent pathogens of Drosophila melanogaster, Serratia marcescens. OMV injection leads to the apparent demise of flies within few hours. We identify a number of host defenses that somewhat protect it from the action of OMVs, namely the systemic humoral immunity pathway Immune deficiency, Prophenol Oxidases 1&2, and the redox active enzymes Dual oxidase, NADPH-oxidase, and Nitric Oxygen Synthase. In contrast, unidentified hemocyte function(s) and the circulating protease Hayan promote the pathogenicity of OMVs. Mechanistically, we find that OMVs promote the activation of the JNK pathway and the transient expression of the pro-apoptotic genes head-involution defective and reaper in at least neurons. Our data suggest that mitochondrially-derived reactive oxygen species promote neuronal cell death that leads to the paralysis of OMV-injected flies. We identify the metalloprotease PrtA as a major virulence factor of OMVs and show that the injection of purified PrtA mimics most of the effects of OMVs. Finally, our data further indicate that PrtA contributes to the pathogenicity of injected Serratia marcescens. This study underscores the potential for OMVs to act as virulence factors that efficiently target the nervous system in vivo despite the blood brain barrier.

immunology↗

Single-Cell and Population-Level Neuromodulation Dynamics in Dual-Electrode Intracortical Stimulation

In neuroprosthetics, intracortical microstimulation (ICMS) recruits cortical networks to evoke brain responses and sensory perceptions. However, multi-electrode ICMS often generates suboptimal percepts compared to single-electrode ICMS, suggesting nonlinear neuromodulation rather than simple summation by multi-electrode ICMS. Yet, the factors and mechanisms underlying this modulation remain poorly understood. To investigate multi-electrode ICMS, we combined two-photon calcium imaging with a well-controlled dual-electrode ICMS in the mouse visual cortex to investigate how neurons integrate converging ICMS inputs at varying intensities. We found that stimulation intensity significantly shapes neuromodulation at both single-cell and population levels. Specifically, low intensities (5-7 {micro}A) have a minimal effect on neural responses. At intermediate intensities (10-15 {micro}A), we observed diverse, nonlinear bipolar modulation--both enhancement and attenuation--at the single-cell level. However, we achieved net enhancement at the population level. At higher intensities (15-20 {micro}A), although the proportion of modulated neurons increased in both enhancement and attenuation directions, the net effect at the population level was neutral (zero modulation). Furthermore, neurons strongly responsive to single-electrode ICMS were more likely to be attenuated, while weaker responding cells exhibited enhanced modulation. The strongest neuromodulatory effects occur at intermediate spatial distances in between the two electrodes. Computational modeling based on spiking neural network composed of adaptive exponential integrate-and-field neurons implicated the importance of inhibitory network dynamics and network variability as key mechanisms. Our experimental data was used to train an advanced deep learning approach, which successfully predicted the neuromodulation patterns induced by dual-electrode ICMS. Our findings reveal intensity- and spatial-dependent rules of neuromodulation by ICMS, providing necessary insights to optimize multi-electrode ICMS for neuroprosthetic applications. Significance statementUnderstanding how cortical neurons integrate concurrent inputs from multi-electrode intracortical microstimulation (ICMS) is essential for advancing neuroprosthetic technologies. We show that dual-electrode ICMS evokes distinct, predictable neuromodulatory effects that depend on (i) stimulation intensity, (ii) a neurons baseline responsiveness to single electrode input, and (iii) its proximity to the electrodes. Low and intermediate intensity dual-electrode ICMS amplifies neural activity compared to single-electrode ICMS, whereas high-intensity stimulation leads to attenuation, limiting net activation.

neuroscience↗

Novel mouse model reveals neurodevelopmental origin of PMM2-CDG brain pathology

Congenital disorders of glycosylation (CDG) are a group of neurogenetic conditions resulting from disruptions in the cellular glycosylation machinery. The majority of CDG patients have compound heterozygous pathogenic variants in the phosphomannomutase 2 (PMM2) gene. Individuals with PMM2-CDG exhibit multi-systemic symptoms, prominently featuring neurological deficits with nearly all patients exhibiting cerebellar hypoplasia and ataxia. To overcome embryonic lethality caused by whole body knock-out of Pmm2 and mimic patient-related compound heterozygous pathogenic variants, we paired a Pmm2 flox allele (Pmm2fl) with a catalytically inactive knock-in allele (Pmm2R137H), commonly present in PMM2-CDG patients. Mice with post-mitotic loss of PMM2 from neurons or astrocytes are indistinguishable from unaffected littermates, including in a broad battery of neurological assessments. In contrast, removal of PMM2 from embryonic neural precursor cells leads to cerebellar hypoplasia, ataxia, seizures, and early lethality. Comprehensive multi-omics profiling, including metabolomics, glycomics, single-cell transcriptomics, proteomics, and glycoproteomics, reveal widespread molecular disturbances throughout the brain, with the cerebellum showing the most pronounced disruption. These findings highlight the heightened dependency of the developing cerebellum on intact N-glycosylation, aligning with clinical observations in PMM2-CDG patients. Importantly, glycoproteomic alterations identified in our mouse model are corroborated in PMM2-CDG patient post-mortem cerebellar tissue, underscoring the translational relevance of our findings and implicating impaired synaptic transmission as a key pathogenic mechanism.

neuroscience↗

Distinct Ca2+ signatures of leptomeningeal fibroblast subgroups in awake mouse brains in health and inflammation

The leptomeninges, composed of the arachnoid mater, and pia mater, contains distinct subgroups of fibroblasts that differ in location and transcriptomic profiles. These fibroblasts contribute to the blood-cerebrospinal fluid barrier under physiological conditions, participate in fibrosis, and support blood-brain barrier integrity during injury and disease. However, their Ca2+ signaling profiles and underlying mechanisms in health and disease remain poorly understood. In this study, we divided leptomeningeal fibroblasts into three subgroups based on their locations: arachnoid fibroblasts, pia mater fibroblasts and perivascular fibroblasts. We employed two-photon microscopy in awake transgenic mice expressing Ca{superscript 2} indicators in leptomeningeal fibroblasts to investigate spontaneous and behaviorally evoked Ca{superscript 2} transients across different fibroblast subgroups. We found that each subgroup exhibits a distinct Ca{superscript 2} activity profile, with pia mater fibroblasts showing the highest-amplitude Ca{superscript 2} transients. Moreover, these fibroblasts displayed unique responses to both whisker air-puff stimulation and locomotion. We further demonstrated, using a chronically implanted cannula beneath the cranial window, that locomotion-associated vasodilation is followed by TRPV4 channel-mediated fibroblast Ca{superscript 2} elevations. Finally, systemic inflammation induced by lipopolysaccharide (LPS) reduced spontaneous Ca{superscript 2} transients in pia mater fibroblasts, likely due to macrophage infiltration following the inflammatory response. For the first time, this study characterizes spontaneous and behaviorally evoked Ca{superscript 2} dynamics in distinct leptomeningeal fibroblast subgroups in awake animals, providing novel insights into the functional roles of leptomeningeal fibroblasts in the healthy and diseased brain.

neuroscience↗

Chromatix: a differentiable, GPU-accelerated wave-optics library

Modern microscopy methods incorporate computational modeling as an integral part of the imaging process, either to solve inverse problems or optimize the optical system design itself. These methods often depend on differentiable optics simulations, yet no standardized framework exists--forcing computational optics researchers to repeatedly and independently implement simulations with limited reusability and performance. These common problems limit the potential impact of computational optics as a field. Here we present Chromatix: an open-source, GPU-accelerated, differentiable wave optics simulation library. Chromatix builds on JAX to democratize fast, parallelized simulation of diverse optical systems and expand the design space in computational optics. Chromatix standardizes a growing collection of optical elements and propagation methods allowing a broad range of applications, which we demonstrate here for snapshot microscopy, holography, and phase retrieval. We demonstrate speed improvements of 2-6x on a single GPU and up to 22x on 8 GPUs.

bioinformatics↗

Resolving the molecular niche of pulmonary fibrosis using cryopreserved human precision cut lung slices

Background and methodsPulmonary fibrosis (PF) manifests locally and heterogeneously in the diseased lung. To uncover mechanistic underpinnings, we have utilized cryopreserved fibrotic human precision-cut lung slices (PCLS), and using single-cell spatial transcriptomics, mapped and interpreted the transcriptomic regulation of effector cell types/states. ResultsCryopreserved-thawed fibrotic human PCLS retained canonical molecular and cellular PF hallmarks including fibroblast and myofibroblast accumulation, epithelial depletion, and vascular remodeling. Notably, these cellular changes were spatially co-incident with 1) collagen-rich regions enriched for extracellular matrix (ECM)-related genes (e.g., COL1A1, SPARC), 2) expanded fibroblast-endothelial crosstalk with enhanced chemokine signaling (CXCL12- CXCR4), 3) integrin-driven mesenchymal signaling targets (ANGPTL-integrin), 4) stress-adapted and immune-interacting Alveolar Type 2 cells with impaired surfactant gene expression, and 5) endothelial reprogramming toward a contractile and profibrotic phenotype. At the transcriptomic level, the spatially-defined fibrotic niche was characterized by increased gene expression related to immune responses (IGKC and IGHG1), fibrosis (collagen, fibronectin, and DCN), mechanotransduction (MYH11, TPM2, ACTG2, ACTA2), immune cell recruitment (CCL2, IL6, ICAM1), ECM remodeling (e.g. thrombospondin 1, THBS1), and decreased gene expression related to surfactant production (SFTPB, SFTPC). At the functional level, the fibrotic niches were defined by the activation of three fibroblast mediating signaling pathways: (1) the matricellular glycoprotein, SPARC, (2) Relaxin signaling, and (3) multiple immunoglobulin transcripts, including IGHA1, IGHG1, IGHG3, and IGKC. ConclusionsWe verify model fidelity, identify both known and unanticipated pro-fibrotic genes, and advocate for the expanded use of spatial transcriptomic measurements using cryopreserved human PCLS for disease modeling and drug discovery.

genomics↗

A prevalent Krt8-to-Krt5 cellular state transition in skin is co-opted by p63 for enamel organ development

Tooth enamel, the hardest vertebrate tissue, is crucial for mastication and dental protection. Its formation depends on the enamel organ (EO), a specialized epithelial structure derived from oral epithelium. How uniform oral epithelium differentiates into diverse EO cell types remains unclear. While p63, an ectodermal development master regulator, is essential for dental placode formation, its specific roles in EO development have been obscured by early arrest in p63 knockout mice. Using single-cell RNA sequencing from mouse incisors, we show p63 expression across all EO cell types with both shared and distinct functions. Through trajectory reconstruction, we identify p63s role in regulating both amelogenic (AmG) and non-AmG lineage commitment during EO development. Comparative transcriptome analyses reveal that p63 regulates the Krt8-to-Krt5 transition during AmG cell differentiation, paralleling its function in skin development. This parallel is reinforced by comparative motif discovery showing shared transcription factor usage, particularly p63 and AP-2 family members. Chromatin accessibility analyses further illustrate that p63 mediates this transition through chromatin landscape remodeling. These findings demonstrate that p63 co-opts the Krt8-to-Krt5 transition mechanism from skin development for EO formation. Summary statementThis study reveals how p63 repurposes a skin keratinization mechanism for tooth enamel formation, providing novel insights into how specialized dental tissues develop and potential therapeutic targets for enamel disorders.

developmental biology↗

Circulating Exosomal PCNA: A Biomarker for Early and Pan-Cancer Detection

Detecting multiple cancers with a single, non-invasive liquid biopsy test remains a challenge, as no universally shared cancer biomarker with clinical significance has been identified in bodily fluids. In this study, we identified proliferating cell nuclear antigen (PCNA), a well-established pathological cancer biomarker in tissue biopsies, as being secreted into peripheral bodily fluids within exosomes. Our research demonstrated that cultured cancer cells continuously release large quantities of exosomal PCNA into their surrounding media. Furthermore, we confirmed its presence in human serum. Most importantly, cancer patients exhibited significantly higher levels of exosomal PCNA in their sera compared to healthy individuals. To assess its diagnostic potential, we evaluated the sensitivity and specificity of exosomal PCNA in a cohort of cancer patients and healthy controls. Receiver operating characteristic (ROC) analysis revealed a sensitivity of 77.2% and a specificity of 94.4%. These findings establish exosomal PCNA in peripheral bodily fluids as a promising universal biomarker for the early detection, diagnosis, and monitoring of multiple cancers through liquid biopsy.

cancer biology↗

Master control genes in the regeneration of rod photoreceptors from endogenous progenitor cells in zebrafish retina

Retinitis Pigmentosa is a chronic retinal degenerative disease characterized by the gradual loss of rod, and later, cone photoreceptors until the individual is completely blind. Regeneration of photoreceptors from endogenous progenitor cells is a possible therapeutic approach, but mammals do not do this naturally. Mammalian models can be induced to generate retinal progenitors from Muller glial cells, but there has been limited success in rod photoreceptor specific regeneration. Unlike mammals, zebrafish have the natural ability to regenerate neurons after injury or disease and can provide insight into the molecular mechanisms of regeneration. In this study, we used a zebrafish model of Retinitis Pigmentosa to investigate the class of progenitors responsible for rod photoreceptor regeneration in the context of chronic disease. Using bioinformatic analyses of single-cell RNA sequencing datasets, we identified master regulator genes responsible for proliferation of retinal progenitors, differentiation of progenitors into rod photoreceptors, and maturation of the new rod photoreceptors. Using transient knockdown of gene expression in adult regenerating retina we determined that e2f1, e2f2, e2f3 and aurkb are critical for proliferation of progenitors, and prdm1a is critical for differentiation of progenitors into rod photoreceptors. This study provides a list of master regulators responsible for the specific regeneration of rod photoreceptors during chronic retinal degeneration. Impact StatementIdentification of master regulating genes that drive the proliferation of progenitor cells and their differentiation specifically into rod photoreceptors provides insight that can be used to develop regenerative therapies for retinal degenerative diseases.

neuroscience↗

Spatially mismatched cerebral blood flow and neuronal activity by intracortical microstimulation

Intracortial microstimulation (ICMS) is widely used in brain-machine interface for neuroprosthetics, particularly with aims of restoring lost sensory and motor functions. However, it remains poorly understood whether neuronal and blood flow responses by ICMS are spatially and temporally matched, as well as their underlying mechanism. Neurovascular coupling (NVC) is the process by which neuronal activity regulates blood flow in the brain to meet local metabolic demands. A hypothetically suboptimal NVC by ICMS may exacerbate the neuronal survival near electrode, contributing to neurodegeneration. In this study, we used wide-field imaging, laser speckle imaging and two-photon imaging in transgenic mice expressing calcium fluorescent indicators in neurons or vascular mural cells to examine this hypothesis. Our results showed blood flow responses are delayed at peak time and prolonged in duration compared with neuronal responses. By varying the stimulation amplitudes, we found that low stimulation intensity lower than 50A preserved NVC. In contrast, high intensity stimulation caused spatially mismatched NVC, i.e. in the adjacent range within 200[~]400 m from electrode tip, elicited blood flow compromises but neuronal activities increase. Ca2+ is the key regulator of contractile tone of vascular mural cells. Our results showed that Ca2+ sensitivity at vascular mural cells, i.e. vessel diameter change per unit of Ca2+ change, was decreased in the adjacent region of electrode, which partially explained the compromised and mismatched NVC, and which likely further lead to ischemia and neurodegeneration. This study offers a new insight into ICMS-associated neuronal and vascular physiology, and provides an important implication towards optimal design of ICMS: low intensities is more neuroprotective than high intensities by preserving NVC and preventing ischemia. Our discoveries pave the way for new research consideration and contribute to the development of more advanced brain-machine interface.

neuroscience↗

Newly discovered and conserved role of IgM against viral infection in an early vertebrate

IgM emerged in jawed vertebrates 500 Mya and remains the most evolutionarily conserved antibody class. However, despite extensive studies on IgM as an ancient antiviral weapon in warm-blooded vertebrates, its role and mechanisms in combating viral infections in early vertebrates remain poorly understood. Here, we found that significant virus-specific sIgM titers were generated in serum and gut mucus of teleost fish that survived infection, and fish lacking sIgM were more susceptible to viral infection. These results challenge the paradigm that IgM and IgT are specialized to systemic and mucosal immunity, respectively. More crucially, our study provides further insight into the role of sIgM in viral neutralization and firstly clarified the mechanism through which teleost sIgM blocks viral infection by directly targeting viral particles. From an evolutionary perspective, our findings indicate that sIgM in both primitive and modern vertebrates follow conserved principles in the development of specialized antiviral immunity.

immunology↗

Voluntary Exercise Attenuates Tumor Growth in a Preclinical Model of Castration-Resistant Prostate Cancer

PurposeTo examine the effects of voluntary exercise training on tumor growth and explore the underlying intratumoral molecular pathways and processes responsible for the beneficial effects of VWR on tumor initiation and progression in a mouse model of Castration-Resistant Prostate Cancer (CRPC). MethodsMale immunodeficient mice (SCID) were castrated and subcutaneously inoculated with human CWR-22RV1 cancer cells to construct CRPC xenograft model before randomly assigned to either voluntary wheel running (VWR) or sedentary (SED) group (n=6/group). After three weeks, tumor tissues were collected. Tumor size was measured and calculated. mRNA expression of markers of DNA replication, Androgen Receptor (AR) signaling, and mitochondrial dynamics was determined by RT-PCR. Protein expression of mitochondrial content and dynamics was determined by western blotting. Finally, RNA-sequencing analysis was performed in the tumor tissues. ResultsVoluntary wheel running resulted in smaller tumor volume at the initial stage and attenuated tumor progression throughout the time course (P < 0.05). The reduction of tumor volume in VWR group was coincided with lower mRNA expression of DNA replication markers (MCM2, MCM6, and MCM7), AR signaling (ELOVL5 and FKBP5) and regulatory proteins of mitochondrial fission (Drp1 and Fis1) and fusion (MFN1 and OPA1) when compared to the SED group (P<0.05). More importantly, RNA sequencing data further revealed that pathways related to pathways related to angiogenesis, extracellular matrix formation and endothelial cell proliferation were downregulated. ConclusionsThree weeks of VWR was effective in delaying tumor initiation and progression, which coincided with reduced transcription of DNA replication, AR signaling targets and mitochondrial dynamics. We further identified reduced molecular pathways/processes related to angiogenesis that may be responsible for the delayed tumor initiation and progression by VWR.

cancer biology↗

Change in brain molecular landscapes following electrical stimulation of the nucleus accumbens

Deep brain stimulation (DBS) targeting the nucleus accumbens (NAc) is a promising therapeutic intervention for treatment-resistant neuropsychiatric disorders such as depression, anxiety, and addiction. However, the molecular mechanisms underlying the clinical efficacy of NAc DBS remain largely unknown. One approach to address this question is by performing spatial gene expression analysis on cells located in different regions of the same circuit following NAc DBS. In this study, we utilized high-resolution spatial transcriptomics (Stereo-seq) to investigate gene expression changes induced by NAc DBS in the mouse brain. Mice were randomly allocated to received continuous electrical stimulation (0.1 mA, 130 Hz) or sham treatment (electrode implanted, no electrical stimulation given) for one week, and subsequent Stereo-seq analysis identified differentially expressed genes (DEGs) across various brain regions. Our findings reveal widespread alterations in synaptic function and neuronal connectivity, particularly in glutamate receptor-expressing neurons in the NAc, which play a key role in the reward circuitry. Functional enrichment analysis highlighted changes in transporter activity and glutamate receptor binding in brain regions such as the anterior cingulate cortex and lateral septal nucleus. Single-cell resolution mapping further identified key molecular players, including Nlgn1, Snca, PDE10a, and Syt1, which are critical for synaptic plasticity and neurotransmitter release, and have been implicated in various psychiatric disorders. These findings shed light on the molecular underpinnings of NAc DBS and provide insights into its therapeutic potential in modulating neural circuits associated with neuropsychiatric disorders.

molecular biology↗

A near-complete genome assembly of the bearded dragon Pogona vitticeps provides insights into the origin of Pogona sex chromosomes

BackgroundThe agamid dragon lizard Pogona vitticeps is one of the most popular domesticated reptiles to be kept as pets worldwide. The capacity of breeding in captivity also makes it emerging as a model species for a range of scientific research, especially for the studies of sex chromosome origin and sex determination mechanisms. ResultsBy leveraging the CycloneSEQ and DNBSEQ sequencing technologies, we conducted whole genome and long-range sequencing for a captive-bred ZZ male to construct a chromosome-scale reference genome for P. vitticeps. The new reference genome is [~]1.8 Gb in length, with a contig N50 of 202.5 Mb and all contigs anchored onto 16 chromosomes. Genome annotation assisted by long-read RNA sequencing greatly expanded the P. vitticeps lncRNA catalog. With the chromosome-scale genome, we were able to characterize the whole Z sex chromosome for the first time. We found that over 80% of the Z chromosome remains as pseudo-autosomal region (PAR) where recombination is not suppressed. The sexually differentiated region (SDR) is small and occupied mostly by transposons, yet it aggregates genes involved in male development, such as AMH, AMHR2 and BMPR1A. Finally, by tracking the evolutionary origin and developmental expression of the SDR genes, we proposed a model for the origin of P. vitticeps sex chromosomes which considered the Z-linked AMH as the master sex-determining gene. ConclusionsOur study provides novel insights into the sex chromosome origin and sex determination of this model lizard. The near-complete P. vitticeps reference genome will also benefit future study of amniote evolution and may facilitate genome-assisted breeding.

genomics↗

Telomere-to-telomere African wild rice (Oryza longistaminata) reference genome reveals segmental and structural variation

Rice (Oryza sativa) is one of the most important staple food crops worldwide, and its wild relatives serve as an important gene pool in its breeding. Compared with cultivated rice species, African wild rice (Oryza longistaminata) has several advantageous traits, such as resistance to increased biomass production, clonal propagation via rhizomes, and biotic stresses. However, previous O. longistaminata genome assemblies have been hampered by gaps and incompleteness, restricting detailed investigations into their genomes. To streamline breeding endeavors and facilitate functional genomics studies, we generated a 343-Mb telomere-to-telomere (T2T) genome assembly for this species, covering all telomeres and centromeres across the 12 chromosomes. This newly assembled genome has markedly improved over previous versions. Comparative analysis revealed a high degree of synteny with previously published genomes. A large number of structural variations were identified between the O. longistaminata and O. sativa. A total of 2,466 segmentally duplicated genes were identified and enriched in cellular amino acid metabolic processes. We detected a slight expansion of some subfamilies of resistance genes and transcription factors. This newly assembled T2T genome of O. longistaminata provides a valuable resource for the exploration and exploitation of beneficial alleles present in wild relative species of cultivated rice.

genomics↗

Androgen deprivation-mediated activation of AKT is enhanced in prostate cancer with TMPRSS2:ERG fusion

TMPRSS2:ERG gene fusion (T:E fusion) in prostate adenocarcinoma (PCa) puts ERG under androgen receptor (AR) regulated TMPRSS2 expression. T:E fusion is associated with PTEN loss, and is highly associated with decreased INPP4B expression, which together may compensate for ERG-mediated suppression of AKT signaling. We confirmed in PCa cells and a mouse PCa model that ERG suppresses IRS2 and AKT activation. In contrast, ERG downregulation did not increase INPP4B, suggesting its decrease is indirect and reflects selective pressure to suppress INPP4B function. Notably, INPP4B expression is decreased in PTEN-intact and PTEN-deficient T:E fusion tumors, suggesting selection for a nonredundant function. As ERG in T:E fusion tumors is AR regulated, we further assessed whether AR inhibition increases AKT activity in T:E fusion tumors. A T:E fusion positive PDX had increased AKT activity in vivo and response to AKT inhibition in vitro after androgen deprivation. Moreover, two clinical trials of neoadjuvant AR inhibition prior to radical prostatectomy showed greater increases in AKT activation in the T:E fusion positive versus negative tumors. These findings indicate that AKT activation may mitigate the efficacy of AR targeted therapy in T:E fusion PCa, and that these patients may most benefit from combination therapy targeting AR and AKT.

cancer biology↗

The neurovascular coupling response of the aged brain is brain-state dependent.

Brain aging lead to reduced cerebral blood flow and cognitive decline, but how normal aging affects neurovascular coupling (NVC) in the awake brain is unclear. Here, we investigated NVC in relation to calcium changes in vascular mural cells (VMCs) in awake adult and aged mice. We show that NVC responses are reduced and prolonged in the aged brain and that this is more pronounced at the capillary level than in arterioles. However, the overall NVC response, measured as the time integral of vasodilation, is the same in two age groups. In adult, but not in aged mice, the NVC response correlated with Ca2+ signaling in VMCs, while the overall Ca2+ kinetics were slower in aged than in adult mice. In particular, the rate of Ca2+ transport, and the Ca2+ sensitivity of VMCs were reduced in aged mice, explaining the reduced and prolonged vasodilation. Spontaneous locomotion was less frequent and reduced in aged mice as compared to young adult mice, and this was reflected in the slow but prolonged NVC and vascular Ca2+ responses. Taken together, our data characterize the NVC in the aged awake brain as slow but prolonged, and underscoring the importance of brain state in understanding age-related mechanisms.

neuroscience↗