A synthetic peptide disturbing GluN2A/SHP1 interaction in dorsal root ganglion attenuated pathological pain.

Src Homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1) interacts specifically with GluN2A subunit of N-methyl-D-aspartate (NMDA) subtype of glutamate receptors in spinal cord dorsal horn. This molecular interaction is involved in the development of GluN2A-dependent spinal sensitization of nociceptive behaviors. Intrathecal application of a GluN2A-derived polypeptide (short for pep-GluN2A) has been shown to disturb spinal GluN2A/SHP1 interaction and inhibit inflammatory pain. Here we found that SHP1 was also located at dorsal root ganglion (DRG) neurons and formed complexes with GluN2A subunit. Peripheral inflammation activated SHP1 in DRG neurons, which promoted GluN2A tyrosine phosphorylation. The SHP1 binding to GluN2A facilitated the glutamate release from primary afferent fibers and exaggerated nociceptive synaptic transmission onto postsynaptic spinal cord neurons. Our data showed that intradermal application of pep-GluN2A disrupted GluN2A/SHP1 interaction in DRG neurons, attenuated the ability of GluN2A subunit-containing NMDA receptors to regulate the presynaptic glutamate release and more importantly, alleviated the pain hypersensitivity caused by carrageenan, complete Freund's adjuvant and formalin. The neuropathic pain induced by spared nerve injury was also ameliorated by intradermal pep-GluN2A application. These data suggested that disruption of GluN2A/SHP1 interaction in DRG neurons generated an effective analgesic action against pathological pain.

Ubiquitination and inhibition of glycine receptor by HUWE1 in spinal cord dorsal horn.

Glycine receptors (GlyRs) are pentameric proteins that consist of α (α1-α4) subunits and/or ß subunit. In the spinal cord of adult animals, the majority of inhibitory glycinergic neurotransmission is mediated by α1 subunit-containing GlyRs. The reduced glycinergic inhibition (disinhibition) is proposed to increase the excitabilities and spontaneous activities of spinal nociceptive neurons during pathological pain. However, the molecular mechanisms by which peripheral lesions impair GlyRs-α1-mediated synaptic inhibition remain largely unknown. Here we found that activity-dependent ubiquitination of GlyRs-α1 subunit might contribute to glycinergic disinhibition after peripheral inflammation. Our data showed that HUWE1 (HECT, UBA, WWE domain containing 1), an E3 ubiquitin ligase, located at spinal synapses and specifically interacted with GlyRs-α1 subunit. By ubiquitinating GlyRs-α1, HUWE1 reduced the surface expression of GlyRs-α1 through endocytic pathway. In the dorsal horn of Complete Freund's Adjuvant-injected mice, shRNA-mediated knockdown of HUWE1 blunted GlyRs-α1 ubiquitination, potentiated glycinergic synaptic transmission and attenuated inflammatory pain. These data implicated that ubiquitin modification of GlyRs-α1 represented an important way for peripheral inflammation to reduce spinal glycinergic inhibition and that interference with HUWE1 activity generated analgesic action by resuming GlyRs-α1-mediated synaptic transmission.

Fever as a first manifestation of advanced gastric adenosquamous carcinoma: a case report.

Gastric adenosquamous carcinoma (ASC) is a rare type of gastric cancer. It is a mixed neoplasm, consisting of glandular cells and squamous cells. It is often diagnosed at an advanced stage, thus carrying a poor prognosis. We describe a case of a 73-year-old male, who presented with refractory fever and an intra-abdominal mass on imaging. He underwent a laparoscopic exploration followed by a successful totally laparoscopic total gastrectomy with D2 lymphadenectomy for gastric cancer. Postoperative pathology revealed primary gastric ASC (T4aN0M0). The patient received adjuvant radiotherapy and chemotherapy with S1 and is alive 20 mo after surgery without recurrence. This is the first case of advanced gastric ASC with fever as the initial presentation treated with totally laparoscopic total gastrectomy reported in the English literature.

Primary adenosquamous carcinoma of the jejunum.

Adenosquamous carcinomas of the small intestine are extremely rare, with only three documented jejunal and three ileal cases being reported in the English-language medical literature. Presented herein is a case of primary jejunal adenosquamous carcinoma in an 80-year-old woman. The jejunal carcinoma consisted predominantly of a squamous component throughout the tumor but peritoneal nodules carrying metastases from the adenocarcinoma element were noted, making it the first case of jejunal adenosquamous carcinoma with metastases from the adenocarcinoma component. The finding that metastases could arise from the minor component of a jejunal adenosquamous carcinoma indicates that an accurate diagnosis must be based upon thorough examination of both the primary and the metastases, not just mesenteric nodule biopsy alone. Histological foci of closely intermingled squamous and glandular components with apparent morphological transition were noted, indicating the pathogenetic possibility that the squamous component might arise by transformation from the glandular element. The squamous component was strongly positive with immunostaining for p63 (nuclear staining) and for cytokeratin 10/13 (cytoplasmic staining), while the adenocarcinoma element was negative. The immunohistochemical results suggest that p63 and cytokeratin 10/13 might be useful in identifying squamous differentiation in jejunal carcinoma.