Molecular neurobiological insight into human nervous tissues is needed to generate next-generation therapeutics for neurological disorders such as chronic pain. We obtained human dorsal root ganglia (hDRG) samples from organ donors and performed RNA-sequencing (RNA-seq) to study the hDRG transcriptional landscape, systematically comparing it with publicly available data from a variety of human and orthologous mouse tissues, including mouse DRG (mDRG). We characterized the hDRG transcriptional profile in terms of tissue-restricted gene coexpression patterns and putative transcriptional regulators, and formulated an information-theoretic framework to quantify DRG enrichment. Relevant gene families and pathways were also analyzed, including transcription factors, G-protein-coupled receptors, and ion channels. Our analyses reveal an hDRG-enriched protein-coding gene set (∼140), some of which have not been described in the context of DRG or pain signaling. Most of these show conserved enrichment in mDRG and were mined for known drug-gene product interactions. Conserved enrichment of the vast majority of transcription factors suggests that the mDRG is a faithful model system for studying hDRG, because of evolutionarily conserved regulatory programs. Comparison of hDRG and tibial nerve transcriptomes suggests trafficking of neuronal mRNA to axons in adult hDRG, and are consistent with studies of axonal transport in rodent sensory neurons. We present our work as an online, searchable repository (https://www.utdallas.edu/bbs/painneurosciencelab/sensoryomics/drgtxome), creating a valuable resource for the community. Our analyses provide insight into DRG biology for guiding development of novel therapeutics and a blueprint for cross-species transcriptomic analyses.

SummaryWe generated RNA sequencing data from human DRG samples and comprehensively compared this transcriptome to other human tissues and a matching panel of mouse tissues. Our analysis uncovered functionally enriched genes in the human and mouse DRG with important implications for understanding sensory biology and pain drug discovery. AbstractMolecular neurobiological insight into human nervous tissues is needed to generate next generation therapeutics for neurological disorders like chronic pain. We obtained human Dorsal Root Ganglia (DRG) samples from organ donors and performed RNA-sequencing (RNA-seq) to study the human DRG (hDRG) transcriptional landscape, systematically comparing it with publicly available data from a variety of human and orthologous mouse tissues, including mouse DRG (mDRG). We characterized the hDRG transcriptional profile in terms of tissue-restricted gene co-expression patterns and putative transcriptional regulators, and formulated an information-theoretic framework to quantify DRG enrichment. Our analyses reveal an hDRG-enriched protein-coding gene set (~140), some of which have not been described in the context of DRG or pain signaling. A majority of these show conserved enrichment in mDRG, and were mined for known drug -gene product interactions. Comparison of hDRG and tibial nerve transcriptomes suggest pervasive mRNA transport of sensory neuronal genes to axons in adult hDRG, with potential implications for mechanistic insight into chronic pain in patients. Relevant gene families and pathways were also analyzed, including transcription factors (TFs), g-protein coupled receptors (GCPRs) and ion channels. We present our work as an online, searchable repository (http://www.utdallas.edu/bbs/painneurosciencelab/DRGtranscriptome), creating a valuable resource for the community. Our analyses provide insight into DRG biology for guiding development of novel therapeutics, and a blueprint for cross-species transcriptomic analyses. peer-reviewed)

COVID-19, caused by the novel coronavirus strain SARS-CoV-2 that emerged in late 2019, has resulted in a global pandemic. COVID-19 was initially believed to occur less frequently in children with relatively mild disease. However, severe disease and varied presentations have been reported in infected children, one of such being intussusception. There have only been three reported cases of intussusception in the pediatric population infected with COVID-19. In this paper, we will discuss the management and treatment of a novel fourth case of COVID-19-associated intussusception. This case is the first reported in the USA and suggests that COVID-19 may be implicated in the development of intussusception. Pediatricians should consider the possibility of intussusception when a child with COVID-19 presents with abdominal pain.

The dorsal root ganglion (DRG) contains sensory neurons that innervate the surface of the body and many visceral organs. Included amongst these neurons are nociceptors, specialized neurons that detect damaging or potentially damaging stimuli, which are required for the detection of acute pain and play a key role in the development and maintenance of chronic pain states. RNA‐seq has recently been used to elucidate the transcriptome of this tissue in mouse and rat but the transcriptome of human DRG has not been explored. We obtained fresh, lumbar DRG tissue from female human donors and performed 75bp paired‐end polyA+ RNA‐sequencing on the Illumina platform. The sequenced fragments were mapped to the Gencode v14 reference transcriptome / hg19 reference genome to yield 80M mapped fragments, and relative transcript abundance in FPKM (Fragments Per Kilobase per Million mapped fragments) was quantified using the Tophat‐Cufflinks toolkit. We compared our RNA‐seq dataset to publicly available mouse DRG RNA‐seq data and performed integrative analysis with RNA‐seq data from several tissues associated with drug side effects (e.g. heart, small intestine, whole brain) to perform an unbiased search for conserved gene expression in DRG across both species. We find that there is broad conservation of known DRG and/or nociceptor enriched genes (e.g. P2XR3, SCN10A, SCN11A, NTRK1, MRGPRD) across mouse and human DRGs. Information theory approaches were used to identify tissue‐specific genes in human and mouse DRG compared to tissues 13 other tissues in human and mouse. We find strong correlation of expression across tissues between species for a few hundred DRG‐enriched transcripts, including known genes enriched in the DRG and previously unidentified ones. A conspicuous DRG enriched gene is F2RL2 which encodes PAR3. PAR3 expression in DRG is amongst the highest for all G protein coupled receptors (GPCRs) in human and mouse and mapping to existing cellular expression databases suggests neuronal expression in a population of nociceptors. To test the potential role of PAR3 in pain, we developed a novel ligand for this receptor using our synthetic tethered ligand discovery platform for PARs and show that it robustly activates calcium signaling in trigeminal ganglion neurons and causes mechanical hypersensitivity after hindpaw injection in mice but is devoid of activity at PAR2. Ongoing experiments are further evaluating the specificity of this compound. Our unbiased, human transcriptome approach to target discovery reveals PAR3 as a novel pain target.Support or Funding InformationNIH grants NS073664 and NS065926

phenotype. We confirmed the over-expression of CD163 in M1 macrophages at 48 and 72 hours after transfection. Using an in vitro scratch assay we also observed that the addition of CD163-blocking antibody, but not isotype control, blocked the efficient and faster wound healing process induced by CD163-overexpressing macrophages. Moreover, the interaction among keratinocytes, fibroblasts and CD163-overexpressing macrophages resulted in an increased CD163 gene expression in these macrophages. CD163 seems to play a critical role in the induction of wound healing by promoting an anti-inflammatory phenotype in macrophages. We further postulate that this approach could promote a more efficient wound healing process following major surgeries, which would reduce the incidence of chronic postoperative pain.

phenotype. We confirmed the over-expression of CD163 in M1 macrophages at 48 and 72 hours after transfection. Using an in vitro scratch assay we also observed that the addition of CD163-blocking antibody, but not isotype control, blocked the efficient and faster wound healing process induced by CD163-overexpressing macrophages. Moreover, the interaction among keratinocytes, fibroblasts and CD163-overexpressing macrophages resulted in an increased CD163 gene expression in these macrophages. CD163 seems to play a critical role in the induction of wound healing by promoting an anti-inflammatory phenotype in macrophages. We further postulate that this approach could promote a more efficient wound healing process following major surgeries, which would reduce the incidence of chronic postoperative pain.

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receptor C3aR1. We have determined that C3aR1 appears to mediate the spinal effects of TLQP-21, as thermal hyperalgesia induced by intrathecally administered TLQP-21 (3 nmol) is inhibited dose-dependently by the C3aR1 antagonist SB290157 (0.1-1 nmol). In addition, we have found that the maintenance of spared nerve injury (SNI)-induced mechanical allodynia is attenuated by intrathecal administration of SB290157 (1 nmol) 28 days post-injury. These effects lasted for two hours postadministration. Quantification of C3aR1 mRNA via qPCR in SNI and Sham subjects is under way to determine if spinal expression of the receptor is altered after nerve injury. C3aR1 is expressed in neurons, microglia, and astrocytes, and we hypothesize that the effects of TLQP-21 are mediated by activation of spinal microglia. We found that stimulation with TLQP-21 (10 uM) elicits calcium transients in cultured primary microglia. Moreover, TLQP-21 appears to induce PGE2 release in a dose-dependent manner in these cells. These preliminary finding are consistent with our previous observations that TLQP-21-induced hyperalgesia is attenuated by administration of the COX-inhibitor indomethacin. Taken together, these results point to the involvement of COX/ PGE2 signaling in the spinal effects of TLQP-21, potentially via a C3aR1-mediated mechanism.