Biology subjects

King, P. H.

Publications and source records attributed to King, P. H..

4 recordsLinked to original sources

bioRxiv2025

Sulfotransferase 4A1 (SULT4a1): A Novel Neuroprotective Protein in Stroke

SULT4a1, a member of the cytosolic sulfotransferase family, is predominantly expressed in neurons and plays potentially vital roles in regulating neural survival and function. SULT4a1 protects against mitochondrial dysfunction and oxidative stress. SULT4a1 levels decrease in experimental stroke models and may play a critical neuroprotective role in mitigating neuronal injury caused by oxygen-glucose deprivation (OGD) and ischemic stroke, as shown in a transient middle cerebral artery occlusion (tMCAO) mouse model. In this study, we investigated the neuroprotective role of SULT4a1 in OGD and tMCAO and highlighted its expression pattern and involvement in maintaining mitochondrial function and reducing oxidative stress, two early pathophysiological features in stroke and related neuronal injury. Our data show that decreased SULT4a1 expression in OGD conditions and in the tMCAO mouse brain leads to enhanced neuronal damage, emphasizing the importance of SULT4a1 in preserving neuronal integrity. Loss of SULT4a1 alone was sufficient to decrease mitochondrial function in mouse cortical neurons. Notably, overexpression of SULT4a1 preserved mitochondrial function, reduced the loss of mitochondrial membrane potential, and diminished oxidative stress, as evidenced by lower reactive oxygen species (ROS) production and reduced protein carbonylation. These results indicate that modulating SULT4a1 expression in stroke could offer a promising strategy for preventing neuronal damage. Indeed, overexpression of SULT4a1 via stereotaxic injection of AAV9 into the mouse brain mitigated tMCAO-related brain injury and functional deficits over time. The findings of this study indicate that SULT4a1 may protect neurons in stroke and related brain injury, possibly by maintaining mitochondrial function and redox homeostasis through mechanisms that are still unknown. It is likely that SULT4a1 regulates neuroprotective processes in both the mitochondria and the cytosol. However, further research is needed to clarify the specific molecular pathways involved in its neuroprotective function.

neuroscience↗

bioRxiv2024

Inhibition of the RNA Regulator HuR mitigates spinal cord injury by potently suppressing post-injury neuroinflammation

BackgroundNeuroinflammation plays a significant role in promoting secondary tissue injury after spinal cord trauma. Within minutes after spinal cord injury (SCI), microglia and astrocytes become activated and produce inflammatory mediators such as TNF-, IL-6, iNOS and COX-2 which induce tissue injury through cytotoxicity, vascular hyperpermeability, and secondary ischemia. The inflammatory cascade is amplified by chemokines such as CCL2 and CXCL1 that promote recruitment of peripheral inflammatory cells into the injured spinal cord. HuR is a key post-transcriptional RNA regulator that controls glial expression of many pro-inflammatory factors by binding to adenylate- and uridylate-rich elements in 3 untranslated regions of the mRNA. SRI-42127 is a small molecule inhibitor that blocks HuR nucleocytoplasmic translocation, a process critical for its regulatory function. The goal of this study was to assess the potential of SRI-42127 for suppressing neuroinflammation after SCI and improving functional outcome. MethodsAdult female mice underwent a contusion injury at the T10 level. SRI-42127 or vehicle was administered intraperitoneally starting 1 h after injury and up to 5 days. Locomotor function was assessed by open field testing, balance beam and rotarod. Immunohistochemistry was used to assess lesion size, neuronal loss, myelin sparing, microglial activation and HuR localization. Molecular analyses of spinal cord and peripheral tissues for expression of inflammatory mediators included qPCR, immunohistochemistry, ELISA, or western blot. Post-SCI pain was assessed by the mouse grimace scale. ResultsSRI-42127 significantly attenuated loss of locomotor function and post-SCI pain. Histologic correlates to these beneficial effects included reduced lesion size, neuronal loss, and an increase in myelin sparing. There was reduced microglial activation at the epicenter with concomitant attenuation of HuR nucleocytoplasmic translocation. Molecular analysis revealed a striking reduction of pro-inflammatory mediators at the epicenter including IL-6, MMP-12, IL-1{beta}, TNF-, iNOS, COX-2, and chemokines CCL2, CXCL1, and CXCL2. Suppression of inflammatory responses extended peripherally including serum, liver, and spleen. ConclusionTargeting HuR after SCI is a viable therapeutic approach for suppressing neuroinflammatory responses after tissue injury and improving functional outcome.

neuroscience↗

bioRxiv2024

The myokine FGF21 associates with enhanced survival in ALS and mitigates stress-induced cytotoxicity

Amyotrophic lateral sclerosis (ALS) is an age-related and fatal neurodegenerative disease characterized by progressive muscle weakness. There is marked heterogeneity in clinical presentation, progression, and pathophysiology with only modest treatments to slow disease progression. Molecular markers that provide insight into this heterogeneity are crucial for clinical management and identification of new therapeutic targets. In a prior muscle miRNA sequencing investigation, we identified altered FGF pathways in ALS muscle, leading us to investigate FGF21. We analyzed human ALS muscle biopsy samples and found a large increase in FGF21 expression with localization to atrophic myofibers and surrounding endomysium. A concomitant increase in FGF21 was detected in ALS spinal cords which correlated with muscle levels. FGF21 was increased in the SOD1G93A mouse beginning in presymptomatic stages. In parallel, there was dysregulation of the co-receptor, {beta}-Klotho. Plasma FGF21 levels were increased and high levels correlated with slower disease progression, prolonged survival, and increased body mass index. In NSC-34 motor neurons and C2C12 muscle cells expressing SOD1G93A or exposed to oxidative stress, ectopic FGF21 mitigated loss of cell viability. In summary, FGF21 is a novel biomarker in ALS that correlates with slower disease progression and exerts trophic effects under conditions of cellular stress.

neuroscience↗

bioRxiv2024

Late-Stage Skeletal Muscle Transcriptome in Duchenne muscular dystrophy shows a BMP4-Induced Molecular Signature

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disease due to loss-of-function mutations in the DYSTROPHIN gene. DMD-related skeletal muscle wasting is typified by an aberrant immune response involving upregulation of TGF{beta} family of cytokines. We previously demonstrated that bone morphogenetic protein 4 (BMP4) is increased in DMD and BMP4 stimulation induces a 20-fold upregulation of Smad8 transcription. However, the role of BMP4 in severely affected DMD skeletal muscle is unknown. We hypothesized that transcriptomic signatures in severely affected human DMD skeletal muscle are driven by BMP4 signaling. Transcriptomes from skeletal muscle biopsies of late-stage DMD vs. non-DMD controls and C2C12 muscle cells with or without BMP4 stimulation were generated by RNA-Seq and analyzed for single transcript differential expression as well as by Ingenuity Pathway Analysis and weighted gene co-expression network analyses. A total of 2,328 and 5,291 transcripts in the human muscle and C2C12 muscle cells, respectively, were differentially expressed. We identified an overlapping molecular signature of 1,027 genes dysregulated in DMD muscle that were induced in BMP4-stimulated C2C12 muscle cells. Highly upregulated DMD transcripts that overlapped with BMP4-stimulated C2C12 muscle cells included ADAMTS3, HCAR2, SERPING1, SMAD8, and UNC13C. The DMD transcriptome was characterized by dysregulation of pathways involving immune function, extracellular matrix remodeling, and metabolic/mitochondrial function. In summary, we define a late-stage DMD skeletal muscle transcriptome that substantially overlaps with the BMP4-induced molecular signature in C2C12 muscle cells. This supports BMP4 as a disease-driving regulator of transcriptomic changes in late-stage DMD skeletal muscle and expands our understanding of the evolution of dystrophic signaling pathways and their associated gene networks that could be explored for therapeutic development.

bioinformatics↗