title: Postnatal expression of the homeobox gene Prrxl1 (Drg11) is increased in inflammatory but not neuropathic pain.
abstract: The paired-type homeodomain transcription factor Prrxl1 (also known as Drg11) is a key regulator of the differentiation and survival of dorsal root ganglia (DRG) and spinal nociceptive neurons in pre- and perinatal stages. Prrxl1(-/-) mice exhibit abnormalities in DRG-spinal projections, defects in superficial dorsal horn structure and neurochemistry, and reduced nociceptive behaviour in several pain tests. Although a low expression of Prrxl1 persists in dorsal root ganglia beyond embryonic development, no data exist on its role in adult life. In this paper we evaluate whether DRG expression of Prrxl1 is affected both in inflammatory and neuropathic models of pain in adult mice. Ipsilateral versus contralateral relative expression of Prrxl1 in the DRG was compared in control and pain animals. The expression of Prrxl1 mRNA in mice with zymosan-induced peripheral inflammation presented a 3.06 ± 0.71-fold-increase in ipsilateral ganglia, which was significantly different from the value observed in control animals. In contrast, a slight, non-statistically significant decrease was detected in the SNI model of neuropathy. Interestingly, the expression of the mRNA splice variant Prrxl1b was unchanged in both pain conditions. Immunohistochemical studies showed an increase in the number of Prrxl1-positive neurons in the inflammatory pain model, which belonged both in the peptidergic and non-peptidergic categories. Our present results point to a role for Prrxl1 in sensitization of nociceptive neurons upon inflammatory pain.
authors.affiliation: Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.
authors.forename: Clara
authors.initials: C
authors.lastname: Monteiro
authors.forename: Sandra
authors.initials: S
authors.lastname: Rebelo
authors.forename: Vasco
authors.initials: V
authors.lastname: Galhardo
authors.forename: Carlos
authors.initials: C
authors.lastname: Reguenga
authors.forename: Deolinda
authors.initials: D
authors.lastname: Lima
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005727:Ganglia, Spinal / Q000276:immunology / Q000502:physiology; D015870:Gene Expression / Q000276:immunology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009414:Nerve Growth Factors / Q000276:immunology / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D009437:Neuralgia / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology*; D009443:Neuritis / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology*; D009619:Nociceptors / Q000276:immunology / Q000502:physiology; D011984:Sensory Receptor Cells / Q000276:immunology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; C433766:Prrxl1 protein, mouse; D014157:Transcription Factors