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Suppression of NF-κB and Wnt signaling by Myd88 disruption in BMDCs.

Expression levels of MYD88 and IRF5 in human and mouse gastric cancer.

Expression levels of MyD88-dependent unregulated genes in the gp130F/F mice.

Supplementary Materials and Methods.

Induction of Tlr2 and Cd14 in regenerating gastric mucosa.

It has been established that COX-2 and downstream signaling by prostaglandin E2 (PGE2) play a key role in tumorigenesis through generation of inflammatory microenvironment. Toll-like receptor (TLR) signaling through myeloid differentiation factor 88 (MyD88) also regulates inflammatory responses in tumors. However, the relationship between these distinct pathways in tumorigenesis is not yet fully understood. We herein investigated the role of MyD88 in gastric tumorigenesis using Gan mice, which develop inflammation-associated gastric tumors due to the simultaneous activation of the COX-2/PGE2 pathway and Wnt signaling. Notably, the disruption of Myd88 in Gan mice resulted in the significant suppression of gastric tumorigenesis with the inhibition of inflammatory responses, even though COX-2/PGE2 pathway is constitutively activated. Moreover, Myd88 disruption in bone marrow–derived cells (BMDCs) in Gan mice also suppressed inflammation and tumorigenesis, indicating that MyD88 signaling in BMDCs regulates the inflammatory microenvironment. We also found that expression of Tlr2 and its coreceptor Cd14 was induced in tumor epithelial cells in Gan mice, which was suppressed by the disruption of Myd88. It has already been shown that TLR2/CD14 signaling is important for stemness of intestinal epithelial cells. These results indicate that MyD88 in BMDCs, together with COX-2/PGE2 pathway, plays an essential role in the generation of the inflammatory microenvironment, which may promote tumorigenesis through induction of TLR2/CD14 pathway in tumor epithelial cells. These results suggest that inhibition of TLR/MyD88 signaling together with COX-2/PGE2 pathway will be an effective preventive strategy for gastric cancer. Cancer Prev Res; 9(3); 253–63. ©2016 AACR.

Supplementary Figure Legends.

Expression levels of TLR2 and CD14 in human and mouse gastric tumors.

IPA analysis of human gastric cancer subtypes.

The ulnar artery usually arises from the brachial artery at the cubital fossa. It descends beneath the flexor carpi ulnaris in the forearm and then terminates at the wrist joint by forming the superficial palmar arch with the contributory radial artery. In the present study, we report a more proximal origin of ulnar artery presenting a superficial course in the lower portion of the upper extremity, termed superficial ulnar artery. Interestingly, this artery lies superficially to a bitendinous palmaris longus, a variant muscle in the forearm. The relation between arterial and muscular variations may be useful during clinical procedures such as angiography, forearm flap and tendon grafting as well as avoiding accidental intra-arterial injection.

In this study, we aimed to evaluate association of ARID1A (AT-rich interacting domain-containing protein 1A) mutation and protein expression with clinicopathology and prognosis of renal cell carcinoma (RCC). Genomic Data Commons (GDC) showed ARID1A was one of the top-ten mutated genes found in kidney cancers and its mutations were found along its sequence. Interestingly, patients with ARID1A mutations had significantly lower survival rate (38%; n=68) comparing to the non-mutated cases (58%; n=192). The results from OSkirc web tool revealed that patients with low expression of ARID1A had significantly shorter overall survival and disease specific survival than those with high ARID1A expression. Immunohistochemistry revealed markedly decreased ARID1A expression in the RCC tissues (n=26), particularly in clear cell RCC (ccRCC) and chromophobe RCC (chRCC). Negative to weak ARID1A expression was significantly associated with ccRCC (grade II) and chRCC subtypes, presence of comorbidity, and low eGFR levels. Finally, ARID1A protein was undetectable in 3/11 cases with ccRCC (grade II) and 2/6 chRCC cases, all of which had metastasis 1−50 months after surgical removal. In conclusion, decreased ARID1A expression is associated with the poor prognosis and metastasis of RCC and thus may serve as the prognostic marker of RCC, particularly ccRCC and chRCC subtypes.

The engagement of the receptor for advanced glycation end-products (receptor for AGEs, RAGE) with diverse ligands could elicit chronic vascular inflammation, such as atherosclerosis. Binding of cytoplasmic tail RAGE (ctRAGE) to diaphanous-related formin 1 (Diaph1) is known to yield RAGE intracellular signal transduction and subsequent cellular responses. However, the effectiveness of an inhibitor of the ctRAGE/Diaph1 interaction in attenuating the development of atherosclerosis is unclear. In this study, using macrophages from Ager+/+ and Ager-/- mice, we validated the effects of an inhibitor on AGEs-RAGE-induced foam cell formation. The inhibitor significantly suppressed AGEs-RAGE-evoked Rac1 activity, cell invasion, and uptake of oxidized low-density lipoprotein, as well as AGEs-induced NF-κB activation and upregulation of proinflammatory gene expression. Moreover, expression of Il-10, an anti-inflammatory gene, was restored by this antagonist. These findings suggest that the RAGE-Diaph1 inhibitor could be a potential therapeutic drug against RAGE-related diseases, such as chronic inflammation and atherosclerosis.

Cadmium (Cd), a toxic heavy metal, produces various forms of environmental contaminations and health problems in human. In this study, we aimed to examine the localization of several apoptotic markers in human placentas from pregnant women who were environmentally exposed to Cd. Twelve pregnant women participated in this analysis and they were divided into 2 groups according to their living areas: high-Cd (H-Cd) and low-Cd (L-Cd) groups. After delivery, the placentas were immediately harvested, and the placental width, length, and weight were measured. The placental Cd concentration was determined by using ICP-MS. The expression of three apoptotic markers, cleaved caspase-3, cleaved lamin A/C, and TUNEL, was examined in immunohistochemistry. In results, the placental Cd concentration in the H-Cd group was higher than that in the L-Cd group. In contrast, a significant decrease in the BW (birth weight):PW (placenta weight) ratio representing the placental nutrient transport function was found in the H-Cd group, and an inverse correlation between placental Cd concentration and BW:PW ratio was demonstrated. Additionally, significant elevations in the expression of cleaved caspase-3, cleaved lamin A/C proteins, and TUNEL were shown in the H-Cd placenta. Moreover, positive correlations were found between the placental Cd concentration and the expression of cleaved caspase-3 and TUNEL. Collectively, our findings suggest that the exposure of pregnant women to environmental Cd might induce Cd to be transferred to the body and then accumulated in the placenta, resulting in disturbance of the placental function and eventual apoptosis.

SUMMARY: The auriculotemporal nerve (ATN) is an important structure lying within a limited area of an infratemporal region (ITR). The ATN is originated from the posterior branch of the mandibular division of the trigeminal nerve (V3). The ATN conveys somatosensory, secretomotor, and parasympathetic fibres of the V3 and gustatory nerve (CN IX). In literature, the most common pattern of the ATN is composed of 2 roots that encloses the middle meningeal artery (MMA). However, in many studies, it has been reported that there are many variations in ATN pattern formation. To study the variation of ATN pattern formation in Thai cadavers, 73 hemifaces from 39 Thai embalmed cadavers were dissected and the relations of the ATN to the MMA were recorded. This study concluded that there were 4 patterns observed in Thai cadavers. The common pattern is 2 roots (67.1 %), 3 roots (15.1 %), 1 root (9.6 %), and 4 roots (8.2 %). Knowledge of this variation in the ATN may be useful in understanding the symptoms of temporo-orofacial pain, paresthesia of temporomandibular joint (TMJ), possible side effects from the TMJ surgery and the efficiency of auriculotemporal nerve block for regional anesthesia of the temporomandibular joint in Thai people.

Cadmium (Cd) is a toxic heavy metal and contamination was reported in soil and rice in several areas of Thailand. Humans are normally exposed to environmental Cd, leading to gradual Cd accumulation in their bodies, including the placenta. DMT-1 is a divalent metal transporter which is found in placental tissue and plays a vital role in the transportation of Fe2+ and Cd2+. This study investigated DMT-1 protein and mRNA expressions in full term human placentas comparing those from high-Cd-contaminated areas (high-Cd group) and low-Cd-contaminated areas (low-Cd group), n = 6 per group. The maternal blood Cd (B-Cd) and placental Cd (P-Cd) of the high-Cd group was significantly raised in comparison with those in the low-Cd group. DMT-1 in the fetal portion of the placentas was localized in the apical and basal portions of the cytoplasm of the syncytiotrophoblastic cells, the endothelium of fetal capillaries which is functional structure of the placental barrier, and was also found in the cytoplasm of Hofbauer cells. Moreover, DMT-1 localization in the maternal portion was also detected in most decidual cells. In addition, the DMT-1 protein and mRNA expressions in the high-Cd group were significantly higher than those in the low-Cd group. Therefore, we suggest that pregnant women, who are exposed to environmental Cd, show an increased level of Cd in their maternal blood and this Cd can accumulate in the placenta. Intracellular Cd may induce DMT-1 mRNA transcription which further translates into DMT-1 protein, which can then function as a reciprocal Cd transporter in placental tissue.

Down-regulation/mutation of AT-rich interactive domain 1A (ARID1A), a novel tumor suppressor gene, has been reported in various cancers. Nevertheless, its role in renal cell carcinoma (RCC) remained unclear and underinvestigated. We thus evaluated carcinogenesis effects of ARID1A knockdown in nonmalignant Madin-Darby canine kidney (MDCK) renal cells using small interfering RNA (siRNA) against ARID1A (siARID1A). The siARID1A-transfected cells had decreased cell death, increased cell proliferation, and cell cycle shift (from G(0)/G(1) to G(2)/M) compared with those transfected with controlled siRNA (siControl). Additionally, the siARID1A-transfected cells exhibited epithelial-mesenchymal transition (EMT) shown by greater spindle index, increased mesenchymal markers (fibronectin/vimentin), and decreased epithelial markers (E-cadherin/zonula occludens-1). Moreover, the siARID1A-transfected cells had increases in migratory activity, nuclear size, self-aggregated multicellular spheroid size, invasion capability, chemoresistance (to docetaxel), Snail family transcriptional repressor 1 expression, and TGF-β1 secretion. All of these siARID1A-knockdown effects on the carcinogenic features were reproducible in malignant RCC (786-O) cells, which exhibited a higher degree of carcinogenic phenotypes compared with the nonmalignant MDCK cells. Finally, immunohistochemistry showed obvious decrease in ARID1A protein expression in human RCC tissues (n = 23) compared with adjacent normal renal tissues (n = 23). These data indicate that ARID1A down-regulation triggers EMT and carcinogenesis features of renal cells in vitro, and its role in RCC could be proven in human tissues.—Somsuan, K., Peerapen, P., Boonmark, W., Plumworasawat, S., Samol, R., Sakulsak, N., Thongboonkerd, V. ARID1A knockdown triggers epithelial‐mesenchymal transition and carcinogenesis features of renal cells: role in renal cell carcinoma.

Objectives Calpains comprise a family of intracellular Ca2+-dependent cysteine proteases and are considered to play roles in various physiological phenomena with limited proteolytic activities against specific substrates. We herein revealed the expression and localization of calpain 3, the muscle-type calpain, in the submandibular gland (SMG) of mice. Design The expression of the mRNA for conventional, ubiquitous calpains 1 and 2 and skeletal muscle-specific calpain 3 was examined in the major salivary glands of mice using RT-PCR, and the expression and localization of calpain 3 protein was examined in the SMG of mice using immunohistochemistry and Western blotting. Results The large catalytic subunits of calpains 1 and 2 and the small regulatory subunit common to calpains 1 and 2 were weakly expressed in the parotid gland, sublingual gland, and SMG at similar levels in males and females. In contrast, the single large catalytic subunit of calpain 3 was expressed predominantly in the SMG at markedly higher levels in males than in females and in a manner dependent on androgens. Immunoreactivity for calpain 3 was mainly localized in cells of the granular convoluted tubules (GCT) that developed preferentially in the male SMG. In GCT cells, calpain 3 immunoreactivity was localized predominantly in the cytosolic region and was absent in the secretory granules. Conclusions These results revealed that the GCT is the primary site of production of calpain 3 in the mouse SMG.

It has been established that COX-2 and downstream signaling by prostaglandin E2 (PGE2) play a key role in tumorigenesis through generation of inflammatory microenvironment. Toll-like receptor (TLR) signaling through myeloid differentiation factor 88 (MyD88) also regulates inflammatory responses in tumors. However, the relationship between these distinct pathways in tumorigenesis is not yet fully understood. We herein investigated the role of MyD88 in gastric tumorigenesis using Gan mice, which develop inflammation-associated gastric tumors due to the simultaneous activation of the COX-2/PGE2 pathway and Wnt signaling. Notably, the disruption of Myd88 in Gan mice resulted in the significant suppression of gastric tumorigenesis with the inhibition of inflammatory responses, even though COX-2/PGE2 pathway is constitutively activated. Moreover, Myd88 disruption in bone marrow–derived cells (BMDCs) in Gan mice also suppressed inflammation and tumorigenesis, indicating that MyD88 signaling in BMDCs regulates the inflammatory microenvironment. We also found that expression of Tlr2 and its coreceptor Cd14 was induced in tumor epithelial cells in Gan mice, which was suppressed by the disruption of Myd88. It has already been shown that TLR2/CD14 signaling is important for stemness of intestinal epithelial cells. These results indicate that MyD88 in BMDCs, together with COX-2/PGE2 pathway, plays an essential role in the generation of the inflammatory microenvironment, which may promote tumorigenesis through induction of TLR2/CD14 pathway in tumor epithelial cells. These results suggest that inhibition of TLR/MyD88 signaling together with COX-2/PGE2 pathway will be an effective preventive strategy for gastric cancer. Cancer Prev Res; 9(3); 253–63. ©2016 AACR.

Un conocimiento exhaustivo de los patrones vasculares del higado, asi como sus posibles variaciones anatomicas son importantes en la planificacion y realizacion de todos los procedimientos quirurgicos hepaticos para evitar comprometer la vascularizacion y posible necrosis del parenquima despues de la cirugia. El tronco celiaco, por lo general, proporciona tres ramas: gastrica izquierda, esplenica y arteria hepatica comun. Las arterias hepaticas izquierda y derecha en general derivan de la arteria hepatica propia, que es una rama de la arteria hepatica comun. El objetivo de este trabajo fue estudiar la incidencia de distribucion del tronco celiaco mediante la documentacion de patrones de ramificacion en 23 cadaveres de Tailandia (17 hombres y 6 mujeres). El estudio se efectuo durante la diseccion de rutina realizada por los estudiantes de medicina en el Departamento de Anatomia de la Facultad de Ciencias Medicas, Universidad de Naresuan, Tailandia. Se observaron las variaciones clinicamente importantes del tronco celiaco. Los resultados mostraron que todos los troncos celiacos surgieron desde la aorta a nivel de la vertebra T12 (17,39%, 4 casos), a nivel del disco intervertebral entre T12 y L1 vertebra (78,26%, 18 casos) y a nivel del tercio superior de la vertebra L1 (4,35%, 1 caso). Encontramos un 95,65% (22 casos) de troncos celiacos normales, es decir, con trifurcacion; mientras que un 4,35% (1 caso) era anormal, con 4 ramos terminales. La arteria hepatica accesoria (AHA) se presento como una rama accesoria del tronco celiaco, ya que existia un patron convencional de las arterias hepaticas izquierda y derecha. Este hallazgo representa una de las raras variaciones anatomicas informada en la literatura. El conocimiento del tronco celiaco y sus ramas aberrantes son importantes en procedimientos como el trasplante hepatico, la anastomosis y una ligadura vascular adecuada.

Cadmium (Cd) has known to produce many adverse effects on organs including placenta. Many essential transporters are involved in Cd transport pathways such as DMT-1, ZIP as well as L-VDCC. Fourteen pregnant women participated and were divided into two groups: high and low Cd-exposed (H-Cd, L-Cd) groups on the basis of their residential areas, Cd concentrations in the blood (B-Cd), urine (U-Cd), and placenta (P-Cd). The results showed that the B-Cd and U-Cd were significantly increased in H-Cd group (p

Metalotioneina (MT) es una proteina, con bajo peso molecular de kDa 6-7 y que fue primero identificada en la corteza renal de equinos como cadmio (Cd)-proteina responsable por la acumulacion natural de Cd en los tejidos. La MT en mamiferos contiene 61 a 68 residuos de aminoacidos, de los cuales estan presentes 18 a 23 residuos de cisteina. La expresion de MT se inicia por la union del factor-1 de transcripcion de metal (MTF-1) a la region reguladora del gen de la MT llamado elementos metalicos responsable (MREs). La induccion de MT a traves de la region MREs puede ser iniciada por varios iones metalicos tales como zinc (Zn), cobre (Cu) y Cd. Sin embargo, el Zn es el unico metal pesado que puede revertir y activar directamente la union ADN de MTF-1. En los mamiferos se expresan cuatro tipos de MT y ellos se denominan metalotioneina-1 (MT1), metalotioneina-2 (MT2), metalotioneina-3 (MT3), y metalotioneina-4 (MT4). MT1 y MT2 se expresan en casi todos los tejidos mientras que MT3 y MT4 son tejido-especifico. La MT es un compuesto clave implicado en la manipulacion intracelular de una variedad de iones metalicos esenciales y no esenciales post-transicionales. Con el fin de evaluar la capacidad de union de metales pesados de MT, se sugiere que este desempena ambos roles tanto en la fijacion intracelular de trazas de elementos de Zn y Cu como en el control de las concentraciones, y neutralizando las influencias perjudiciales a la exposicion de elementos toxicos.

Keratin 5 (K5) is a marker of basal progenitor cells in the epithelia of a number of organs. During prenatal development of the submandibular gland (SMG) in mice, K5(+) progenitor cells in the developing epithelia play important roles in its organogenesis. Although K5(+) cells are also present in the adult mouse SMG and may function in tissue regeneration, their histological localization has not yet investigated in detail. In the present study, we examined the immunohistochemical localization of K5 in the SMG in adult and postnatal developing mice. At birth, K5 immunoreactivity was detected in the entire duct system, in which it was localized in the basal cells of a double-layered epithelium, but was not detected in the terminal tubule or myoepithelial cells. At postnatal weeks 1-3, with the development of intercalated ducts (ID), striated ducts (SD), and excretory ducts (ED), K5-immunoreactive basal cells were gradually restricted to the ED and the proximal double-layered portions of the ID connecting to the SD. At the same time, K5 immunoreactivity appeared in myoepithelial cells, in which its positive ratio gradually increased. In adults, K5 immunoreactivity was localized to most myoepithelial cells, most basal cells in the ED, and a small number of ID cells at the boundary between the ID and SD in the female SMG or between the ID and granular convoluted tubules in the male SMG. These results suggest that K5 is a marker of differentiated myoepithelial cells and duct progenitor cells in the mouse SMG.

Un metal toxico, el cadmio (Cd), se puede acumular en organos humanos. La placenta se utiliza, por lo general, como organo indicador de la exposicion a Cd. Nuestro objetivo fue investigar la diferente morfologia placentaria entre las placentas con baja y alta acumulacion de Cd. Las muestras fueron recolectadas de 14 mujeres embarazadas que residian areas con alta (grupo H-Cd) y baja contaminacion por Cd (grupo L-Cd). Las concentraciones de Cd en la sangre (B- Cd), orina (U-Cd) y placentas (P-Cd) se midieron por ICP-MS y AAS. La apariencia morfologica de las placentas fue examinada usando cortes histologicos tenidos con H-E. Los resultados mostraron que los niveles de B-Cd, U-Cd y P-Cd fueron significativamente mayores en el grupo H-Cd (p= 0,001). Por otra parte, el B-Cd se correlaciono positivamente con las concentraciones de U-Cd (rs= 0,854, p = 0,000 ) y P-Cd (rs= 0,823, p = 0,000). Las apariciones de nodos sinciciales (NS) y depositos fibrinoides (Fd) fueron mayores en el grupo H-Cd (rs= 0,007, p= 0,026). Los ND se correlacionaron positivamente con los Fd (rs= 0,572, p= 0,032) y la concentracion de P-Cd (rs= 0,766, p = 0,001). Aunque caracteristicas de corioamnitis e inflamacion de la decidua se encontraron en ambos grupos, su aparicion en el grupo H-Cd parecio ser mas grave que en el grupo L-Cd. A partir de estos resultados, sugerimos que el nivel alto de Cd en la placenta puede estar involucrado en los cambios morfologicos, especialmente el aumento de NS y Fd, los que probablemente alteran la relacion entre la circulacion materna y fetal.

金沢大学医薬保健研究域医学系, Objectives: The purpose of this study was to investigate bone morphogenetic protein (BMP) 2 expression after implantation of a statin and recombinant human BMP-2 (rhBMP-2) and to compare the bone regeneration capability of these substances in the rabbit nasal bone using immunohistologic methods. Study design: Twelve adult male Japanese white rabbits (n = 12; age 12-16 weeks, weight 2.5-3.0 kg) were divided into 3 experimental groups and 1 control group. A total of 48 bone defects, 4 per rabbit, were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 1 group was implanted with 10 mg of a statin dissolved in 0.2 mL water with an atelocollagen sponge (ACS); the second group was implanted with 5 μg rhBMP-2 with an ACS; and in the third group only the ACS was implanted. No material was implanted in the control group. Animals were killed at 1, 2, and 4 weeks after surgery. The parts that had been operated on were removed and prepared for histologic assessment. The expression of BMP-2 was evaluated using immunohistochemistry, and double-immunostaining for BMP-2 and Ki-67 was observed by fluorescent microscopy. Results: No significant differences were observed between the statin/ACS group and rhBMP-2/ACS group at 1, 2, and 4 weeks after surgery. The number of cells which stained positively for BMP-2 increased significantly in both of the implanted groups compared with the control group (P < .0001). The positive fluorescent double-immunostaining for BMP-2 and Ki-67 was similar in both implanted groups. Conclusion: This study suggests that statin/ACS implants show BMP-2 expression and osteoinductive activity that is similar to those of rhBMP-2/ACS implants. © 2009 Mosby, Inc. All rights reserved..

金沢大学医薬保健研究域医学系, In the submandibular gland (SMG) of mice, a duct portion called the granular concvoluted tubule (GCT) is developed preferentially in males with puberty. This sexual dimorphism is androgen-dependent, but the underlying molecular mechanisms are unclear. We have demonstrated that the expression of a transcription factor JunD is regulated in association with the androgen-induced differentiation of GCT cells from striated duct (SD) cells. Menin, a nuclear protein encoded by the MEN1 tumor-suppressor gene, is known to bind JunD, thereby inhibiting its activity. In the present study, we examined the expression of menin in the mouse SMG by use of Northern blotting, Western blotting, and immunohistochemistry. Immunoreactivity for menin was higher in the female than male gland, and localized to the nuclei of intercalated duct cells and a subpopulation of SD cells. In contrast, GCT cells in males appeared negative for menin. The levels of menin in the SMG were increased with castration in males and decreased by repeated administration of testosterone to females or to castrated males. After a single administration of testosterone to females, many SD cells newly gained nuclear menin, which was lost as the cells converted to GCT cells by 48 hrs. These patterns of the expression and localization of menin were quite similar to those of JunD. Furthermore, the coimmunoprecipitation analysis of the SMG homogenates indicated that menin binds JunD in vivo. The present study suggests that the JunD-menin complex plays significant roles in the androgen-dependent differentiation of the duct system in the mouse SMG. © 2008 Tohoku University Medical Press.

We characterized a cDNA clone derived from the female mouse submandibular gland (SMG). The transcript of this cDNA was approximately 1.2 kb in size and predicted to code a 165-amino acid protein with a putative signal peptide for a secretory pathway. This protein, named submandibular androgen-repressed protein (SMARP), had homology in the N-terminal region with members of the glutamine/glutamic acid-rich protein (GRP) family from rats. Northern blot analysis revealed that SMARP mRNA is expressed, out of the major mouse organs, only in the SMG and exorbital lacrimal gland (LG), with much more abundance in the former. For the SMG, the level of SMARP mRNA was 36 times higher in females than males, whereas for the LG it was 28 times higher in males than females. Furthermore, the level of SMARP mRNA was increased in the SMG but reduced in the LG with castration in males, whereas it was reduced in SMG but increased in LG after administration of testosterone in females or castrated males. In situ hybridization detected the signal for SMARP mRNA in the female SMG, and immunohistochemistry detected the signal for SMARP protein in the female SMG and male LG. In the female SMG, SMARP mRNA, and protein were localized intensively in a subpopulation of acinar cells, whereas in the male LG, SMARP protein was distributed diffusely in all acinar cells. These results suggested that SMARP is a secretory protein whose expression is regulated by androgens negatively in the SMG and positively in the LG.

We cloned a rat gene that is expressed primarily in the sublingual gland and named the predicted 503 amino-acid protein SLAMP (sublingual acinar membrane protein). SLAMP has 63% homology with human ERGIC-53-like protein, a member of the family of animal L-type lectins. Using a cDNA probe for SLAMP mRNA and rabbit antisera against SLAMP, we examined the expression and localization of SLAMP in major rat organs and tissues. With both Northern and Western blot analyses, abundant expression of SLAMP was demonstrated predominantly in the sublingual gland, with single sizes of the mRNA and protein 1.8 kb and 50 kDa, respectively, but not in other organs or tissues, including the parotid and submandibular glands. With immunohistochemistry, SLAMP was localized to the mucous acinar cells, but not to the serous demilunes or the duct system. With immunoelectron microscopy, SLAMP was localized predominantly to regions corresponding to the ER-Golgi intermediate compartment. Besides the sublingual gland, SLAMP immunore-activity was also demonstrated in mucous cells of the minor salivary glands in oral cavity and of Brunner's glands in the duodenum. These results suggested that rat SLAMP plays a specific role in the early secretory pathway of glycoproteins in specific types of mucous cells.