Biology subjects

Schwulst, S. J.

Publications and source records attributed to Schwulst, S. J..

3 recordsLinked to original sources

bioRxiv2024

antiCD49d Ab treatment ameliorates age-associated inflammatory response and mitigates CD8 T cell cytotoxicity after traumatic brain injury

Patients aged 65 years and older account for an increasing proportion of patients with traumatic brain injury (TBI). Older TBI patients experience increased morbidity and mortality compared to their younger counterparts. Our prior data demonstrated that by blocking 4 integrin, anti-CD49d antibody (aCD49d Ab) abrogates CD8+ T-cell infiltration into the injured brain, improves survival, and attenuates neurocognitive deficits. Here, we aimed to uncover how aCD49d Ab treatment alters local cellular responses in the aged mouse brain. Consequently, mice incur age-associated toxic cytokine and chemokine responses long-term post-TBI. aCD49d Ab attenuates this response along with a T helper (Th)1/Th17 immunological shift and remediation of overall CD8+ T cell cytotoxicity. Furthermore, aCD49d Ab reduces CD8+ T cells exhibiting higher effector status, leading to reduced clonal expansion in aged, but not young, mouse brains with chronic TBI. Together, aCD49d Ab is a promising therapeutic strategy for treating TBI in the older people. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/596673v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@97311aorg.highwire.dtl.DTLVardef@18a86borg.highwire.dtl.DTLVardef@d9162forg.highwire.dtl.DTLVardef@3f8d06_HPS_FORMAT_FIGEXP M_FIG C_FIG Aged brains after TBI comprise two pools of CD8+ T cells. The aged brain has long been resided by a population of CD8+ T cells thats exhaustive and dysfunctional. Post TBI, due to BBB impairment, functional CD8+ T cells primarily migrate into the brain parenchyma. Aged, injury-associated microglia with upregulated MHC class I molecules can present neoantigens such as neuronal and/or myelin debris in the injured brains to functional CD8+ T, resulting in downstream CD8+ T cell cytotoxicity. aCD49d Ab treatment exerts its function by blocking the migration of functional effector CD8+ T cell population, leading to less cytotoxicity and resulting in improved TBI outcomes in aged mice.

immunology↗

bioRxiv2018

Traumatic brain injury-associated microglia adopt longitudinal transcriptional changes consistent with long-term depression of synaptic strength

Traumatic brain injury (TBI) is an under-recognized public health threat. Even mild brain injury, or concussions, may lead to long-term neurologic impairment. Microglia play a fundamental role in the development and progression of this subsequent neurologic impairment. Despite this, a microglia-specific injury signature has yet to be identified. In the current study we hypothesized that TBI-associated microglia would adopt longitudinal changes in their transcriptional profile associated with pathways linked to the development of motor, cognitive, and behavioral disorders. C57BL/6 mice underwent TBI via a controlled cortical impact and were followed longitudinally. FACSorted microglia from TBI mice were subjected to RNA-sequencing at 7, 30, and 90 days post-injury. We identified 4 major patterns of gene expression corresponding to the host defense response, synaptic potentiation, lipid remodeling, and membrane polarization. In particular, significant upregulation of genes involved in long-term synaptic potentiation including Ptpn5, Shank3, and Sqstm1 were observed offering new insight into a previously unknown role of microglia in the weakening of synaptic efficacy between neurons after brain injury.

neuroscience↗

bioRxiv2018

Monocyte depletion attenuates the development of posttraumatic hydrocephalus and preserves white matter integrity after traumatic brain injury

Monocytes are amongst the first cells recruited into the brain after traumatic brain injury (TBI). We have shown monocyte depletion 24 hours prior to TBI reduces brain edema, decreases neutrophil infiltration and improves behavioral outcomes. Additionally, both lesion and ventricle size correlate with poor neurologic outcome after TBI. Therefore, we aimed to determine the association between monocyte infiltration, lesion size, and ventricle volume. We hypothesized that monocyte depletion would attenuate lesion size, decrease ventricle enlargement, and preserve white matter in mice after TBI. C57BL/6 mice underwent pan monocyte depletion via intravenous injection of liposome-encapsulated clodronate. Control mice were injected with liposome-encapsulated PBS. TBI was induced via an open-head, controlled cortical impact. Mice were imaged using magnetic resonance imaging (MRI) at 1, 7, and 14 days post-injury to evaluate progression of lesion and to detect morphological changes associated with injury (3D T1- weighted MRI) including regional alterations in white matter patterns (multi-direction diffusion MRI). Lesion size and ventricle volume were measured using semi-automatic segmentation and active contour methods with the software program ITK-SNAP. Data was analyzed with the statistical software program PRISM. No significant effect of monocyte depletion on lesion size was detected using MRI following TBI (p=0.4). However, progressive ventricle enlargement following TBI was observed to be attenuated in the monocyte-depleted cohort (5.3 {+/-} 0.9mm3) as compared to the sham-depleted cohort (13.2 {+/-} 3.1mm3; p=0.02). Global white matter integrity and regional patterns were evaluated and quantified for each mouse after extracting fractional anisotropy maps from the multi-direction diffusion-MRI data using Siemens Syngo DTI analysis package. Fractional anisotropy values were preserved in the monocyte-depleted cohort (123.0 {+/-} 4.4mm3) as compared to sham-depleted mice (94.9 {+/-} 4.6mm3; p=0.025) by 14 days post-TBI. The MRI derived data suggests that monocyte depletion at the time of injury may be a novel therapeutic strategy in the treatment of TBI. Furthermore, non-invasive longitudinal imaging allows for the evaluation of both TBI progression as well as therapeutic response over the course of injury.

neuroscience↗