Biology subjects

Williams, K. C.

Publications and source records attributed to Williams, K. C..

8 recordsLinked to original sources

bioRxiv2025

DMEM, or Opti-MEM, that is the Question: An Important Consideration for Extracellular Vesicle Isolation and their Downstream Applications.

Serum-free synthetic media are frequently used as an alternative to extracellular vesicle-depleted serum containing media (EV-DEP) for EV production. However, the impact of this medium on EV biogenesis, release, and composition remains poorly understood. Here, we comprehensively characterised EV release by MDA-MB-231 or HEK-293T cells cultured in EV-DEP DMEM versus a serum-free synthetic medium, Opti-MEM. In Opti-MEM culture, cells released significantly more CD9- and CD63-positive EVs compared to EV-DEP DMEM. Proteomic analysis revealed that EVs from EV-DEP DMEM contained more histones and bovine proteins. Cells cultured in Opti-MEM released a substantially higher proportion of small-EVs derived from the sphingomyelinase-MVB pathway (60%) compared to EV-DEP DMEM (30%). Conversely, cells cultured in EV-DEP DMEM were more reliant upon the ROCK kinase pathway to release ectosomes (45 %) compared to OptiMEM (15 %). Where cells cultured in EV-DEP DMEM employed RabGTPase-dependent mechanisms for MVB-derived EV release (Rab3d, Rab27a, and Rab27b), cells cultured in Opti-MEM did not. Given that cells cultured in Opti-MEM vs EV-DEP DMEM produce EVs with different protein signatures from distinct molecular pathways, the choice of medium should be carefully considered when designing EV studies - particularly if they are to be used in therapeutic or immunological experiments.

cell biology↗

bioRxiv2025

Invadopodia-Mediated Remodeling of the Lymphatic Endothelium Drives Cancer Cell Lymphatic Dissemination and is Regulated by a CCR7-Vav2-Rac3 Signaling axis.

Cancer cell invasion across a lymphatic endothelial barrier and subsequent colonization of regional lymph nodes often marks the first stage of metastatic dissemination. Lymphatic vessels facilitate the escape of cancer cells and can support further metastatic dissemination. Although the clinical and experimental evidence supports a role for lymph node metastases in promoting metastatic spread, the mechanism employed by cancer cells to navigate a lymphatic endothelium and enter lymphatic vessels is poorly characterized. To investigate this, we assessed the interactions between cancer cells and lymphatic endothelial cells and found that Tks5-positive structures, termed invadopodia, remodel lymphatic endothelial junctions. Loss of Tks5 impaired cancer cell invasion across a lymphatic endothelium and significantly reduced lymph node and lung metastasis in a mouse model of breast cancer progression. Surgical removal of the axillary and brachial lymph nodes prior to orthotopic cancer cell injection resulted in a significant reduction in lung tumor burden, further demonstrating the significance of lymph node metastases to metastatic tumor burden. Next, using breast cancer patient primary tumors we found that elevated expression of CCR7, a chemokine receptor, significantly associated with lymph node metastasis. CCR7 localized to invadopodia and promoted cancer cell invasion across lymphatic endothelium, both in the presence and absence of its canonical ligand CCL19. Tyrosine phosphorylation of CCR7 directed the recruitment of Vav2 and activation of Rac3. Our findings highlight a role for lymphatic metastases in promoting distant metastasis and establish a mechanism by which cancer cells breach a lymphatic endothelium.

cancer biology↗

bioRxiv2025

GABA-GABA_A Receptor Signaling Orchestrates Invasion and Metastasis in Triple Negative Breast Cancer

Cancer is a leading cause of death globally, with the majority of cancer-related deaths resulting from cancer metastasis -the process by which cancer cells disseminate to distant sites. To metastasize, cancer cells acquire traits in support of diverse cellular processes that enable dissemination, survival, and colonization. Tumor cell dissemination requires invasion at local and distant sites and this process can be influenced by intrinsic and extrinsic factors. Here, we investigate the role of the neurotransmitter gamma-aminobutyric acid (GABA) in triple-negative breast cancer (TNBC) invasion and metastasis. TNBC cells increased invasion in response to GABA and this was found to be mediated through the GABAA receptor family. TNBC cell lines were found to be responsive to exogenous GABA and also produced endogenous GABA. Pharmacological inhibition of GABAA receptors reduced TNBC invasion and cancer cell dissemination and resulted in inhibition of GSK3 activity. TNBC cell lines were found to express the GABRE subunit and loss of GABRE impaired GABA-mediated invasion and tumor cell dissemination. These findings support a role for GABA signaling through GABAA receptors in mediating TNBC progression.

cancer biology↗

bioRxiv2023

Subcortical volumes, frontal cortical thickness, and pro-inflammatory cytokines in schizophrenia versus methamphetamine-induced psychosis

Background and HypothesisClinical features of schizophrenia and methamphetamine-induced psychosis (MAP) have significant overlap. Schizophrenia is associated with alterations in subcortical volumes and cortical thickness and pro-inflammatory cytokines, that may correlate with clinical features. However, analogous work on MAP is lacking. We hypothesise decreased frontal cortical thickness, amygdala and hippocampal volumes in schizophrenia and MAP compared to controls, with increased basal ganglia in schizophrenia compared to MAP. Study DesignParticipants included n=36 schizophrenia, n=27 MAP and 32 age- and sex-matched healthy controls. Diagnosis and symptom severity were determined with the Structured Clinical Interview for Axis I Disorders, and the Positive and Negative Syndrome Scale, respectively. Structural T1-weighted images were acquired using a 3-Tesla magnetic resonance imaging scanner. Serum peripheral cytokine concentrations were measured using a multiplex bead array. Study ResultsSchizophrenia and MAP participants showed decreased left amygdala volumes and frontal cortical thickness compared to controls. Schizophrenia participants had increased bilateral caudate, putamen, and nucleus accumbens (NAcc) volumes compared to controls, and greater right globus pallidus and NAcc volumes compared to MAP. Decreased left amygdala volumes and frontal cortical thickness were significantly associated with longer illness duration in schizophrenia and methamphetamine use in MAP. No significant differences were found in cytokine levels between groups or associations with neuroimaging measures. ConclusionsThis study highlights overlaps and differences in the psychobiology of schizophrenia and MAP.The novel discovery of increased globus pallidus and NAcc volumes in schizophrenia compared with MAP may show important distinctions in the neurobiology between these two conditions.

neuroscience↗

bioRxiv2021

Strategic Leadership Coaching supports Young Executives decision-making

Decision-making is central to daily function for executives in any organisation. Strategic leadership coaching (SLC) is an effective way to support complex decision-making, yet empirical neuroscientific data to support is lacking. The purpose of this study was to investigate the effects of SLC on young executives cortical arousal and their neural circuitry activation during the completion of computerized tasks which require activation of decision-making circuitry. We hypothesised SLC would improve cortical arousal when engaged with decision-making tasks, specifically increased electroencephalography (EEG) relative alpha band activity and improved neural circuitry engagement, measured as increased amplitude of event-related potential wave components. This study included thirty-one young male executives, of which eighteen underwent 8 sessions of SLC over two months. EEG records were collected thrice from those who underwent SLC (prior, post, and two months post), and twice from the control group (two months apart). The EEG recording session included completion of two decision-making tasks, an Iowa gambling task and Stroop colour-word conflict task. Finding, SLC increased alpha band activity over left frontal and central electrodes, and increased right parietal N170 amplitude and left parietal P300 amplitude. These findings support our hypothesis, as SLC improved cognitive cortical resources (enhanced alpha) which in turn permitted greater efficiency within decision-making circuitry (increased wave component amplitudes). This study provides the first and necessary neurobiological evidence to support and develop this line of research in SLC, and other forms of coaching, as it adds significant value.

neuroscience↗

bioRxiv2020

A Versatile Soluble Siglec Scaffold for Sensitive and Quantitative Detection of Glycan Ligands

Sialic acid-binding immunoglobulin-type lectins (Siglecs) are immunomodulatory receptors that are regulated by their glycan ligands. A growing connection between Siglecs and human disease motivates improved methods to detect Siglec ligands. Here, we describe a new versatile set of Siglec-Fc proteins for glycan ligand detection. Enhanced sensitivity and selectivity are enabled through multimerization and avoiding Fc receptors, respectively. Using these Siglec-Fc proteins, Siglec ligands were systemically profiled on healthy and cancerous cells and tissues, revealing many unique patterns. Additional features enable the production of small, homogenous Siglec fragments and development of a quantitative ligand-binding mass spectrometry assay. Using this assay, the ligand specificities of several Siglecs were clarified. For CD33, we demonstrate that it recognizes both 2-3 and 2-6 sialosides in solution and on cells, which has implications for its link to Alzheimers disease susceptibility. These soluble Siglecs reveal the abundance of their glycan ligands on host cells as self-associated molecular patterns.

biochemistry↗

bioRxiv2020

Brain tissue transcriptomic analysis of SIV-infected macaques identifies Poly (ADP-ribose) polymerases (PARPs) as potential biomarkers for neuropathogenesis.

BackgroundDespite improvements in antiretroviral therapy, human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) remain prevalent in subjects undergoing therapy. HAND significantly affects individuals quality of life, as well as adherence to therapy, and, despite the increasing understanding of neuropathogenesis, no definitive diagnostic or prognostic marker has been identified. ResultsWe investigated transcriptomic profiles in frontal cortex tissues of Simian immunodeficiency virus (SIV)-infected Rhesus macaques sacrificed at different stages of infection. Gene expression was compared among SIV-infected animals (n=11), with or without CD8+ lymphocyte depletion, based on detectable (n=6) or non-detectable (n=5) presence of the virus in frontal cortex tissues. Significant enrichment in activation of monocyte and macrophage cellular pathways was found in animals with detectable brain infection, independently from CD8+ lymphocyte depletion. In addition, transcripts of four poly (ADP-ribose) polymerases (PARPs) were up-regulated in the frontal cortex, which was confirmed by real-time polymerase chain reaction. ConclusionsOur results shed light on involvement of PARPs in SIV infection of the brain and their role in SIV-associated neurodegenerative processes. Inhibition of PARPs may provide an effective novel therapeutic target for HIV-related neuropathology.

pathology↗

bioRxiv2018

Monocyte Infection Dynamics Shape HIV-1 Phyloanatomy in the Peripheral Blood

Human immunodeficiency virus (HIV) RNA and DNA have been isolated from patient monocytes, an immune cell population that is quite different in several aspects from the canonical T-cell viral target. Because monocytes are migratory and resilient to both natural and synthetic antiviral defenses, knowledge of the contribution of monocyte infection to ongoing viral evolution and spread in vivo is of significant interest for drug development and treatment strategies. Using single viral genome sequencing from different peripheral blood compartments and phyloanatomic statistical inference, we demonstrate that productively infected monocytes follow an evolutionary trajectory that is distinct from peripheral T cells during multiple stages of disease progression. Gene flow and selection analysis reveal plasticity in the source of monocyte infection and in the region of the HIV envelope glycoprotein that experiences selection pressure across individuals. The findings, thus, point to a potential reservoir showing a range of infection and transmission dynamics, for which the current universal, T cell-targeted treatment strategies would be inadequate.\n\nAuthor summaryHuman immunodeficiency virus is a rapidly evolving virus, allowing its genetic material to act as a fingerprint for epidemiological processes among, as well as within, individual infected hosts. In this study, sampling of viral RNA from plasma and differing infected immune cell populations from the peripheral blood was undertaken for three separate individuals in order to infer such processes. The results revealed a productively infected monocyte cell population, for which distinct selection pressures were linked to differing spatiotemporal origins of infection. In light of previous evidence of the migratory nature of these cells and resilience to both natural and synthetic antiviral defenses, this study underscores the importance of further investigation into the role of monocytes, and monocyte-rich tissues, as viral reservoirs during treatment of HIV with antiretroviral therapy.

evolutionary biology↗