Expression of neuropsin mRNA in the mouse embryo and the pregnant uterus

Pathological changes in mice with long term cuprizone administration

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). In MS, a long disease duration is known to be a strong risk factor for converting the clinical course of the disease from relapse remitting MS to secondary progressing MS. There is a hypothesis that long sustained demyelination may exhaust neurons, however, pathological changes induced in neurons following demyelination remain unknown. Cuprizone administration can induce and sustain demyelination in the mouse CNS. We examined pathological changes in mice following long sustained demyelination caused by up to 34-week cuprizone administration. Twelve-week cuprizone administration induced severe demyelination in the cerebral cortex, corpus callosum and deep cerebellar nuclei. Demyelination persisted up to 34 weeks, as shown by myelin basic protein immunohistochemistry. In contrast, cuprizone administration developed demyelination in the striatum by week 34. In these demyelinated regions, no neuronal loss was observed. However, in the striatum and deep cerebellar nuclei, cuprizone-induced demyelination changed the intracellular distribution of parvalbumin (PV). Furthermore, in the striatum, there was an increase in PV in the demyelinated axons and most PV immunoreactivity did not co-localize with SMI32 immunoreactivity in mice with 34-week cuprizone administration. Further, mice with 34-week cuprizone administration showed motor coordination dysfunction in the balance beam test. However, 12-week withdrawal from the cuprizone diet induced remyelination in the regions and motor coordination dysfunction recovered. These results indicate that 34-week cuprizone administration induces and sustains demyelination and results in reversible motor coordination dysfunction. The change of intracellular PV distribution suggests that PV may protect demyelinated axons by Ca²⁺ buffering. This model may be useful to investigate pathological and behavioral changes following demyelination in the CNS.

Kallikrein cascades in traumatic spinal cord injury: in vitro evidence for roles in axonopathy and neuron degeneration

Kallikreins (KLKs) are a family of 15 secreted serine proteases with emerging roles in neurologic diseases. To illuminate their contributions to the pathophysiology of spinal cord injury (SCI), we evaluated acute through chronic changes in the immunohistochemical appearance of 6 KLKs (KLK1, KLK5, KLK6, KLK7, KLK8, and KLK9) in postmortem human traumatic SCI cases, quantified their RNA expression levels in experimental murine SCI, and assessed the impact of recombinant forms of each enzyme toward murine cortical neurons in vitro. Temporally and spatially distinct changes in KLK expression were observed with partially overlapping patterns between human and murine SCI, including peak elevations (or reductions) during the acute and subacute periods. Kallikrein 9 showed the most marked changes and remained chronically elevated. Importantly, a subset of KLKs (KLK1, KLK5, KLK6, KLK7, and KLK9) were neurotoxic toward primary neurons in vitro. Kallikrein immunoreactivity was also observed in association with swollen axons and retraction bulbs in the human SCI cases examined. Together, these findings demonstrate that elevated levels of a significant subset of KLKs are positioned to contribute to neurodegenerative changes in cases of CNS trauma and disease and, therefore, represent new potential targets for the development of neuroprotective strategies.

Pattern of expression of the CREG gene and CREG protein in the mouse embryo

The cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein that inhibits cell proliferation and/or enhances differentiation. CREG is widely expressed in adult tissues such as the brain, heart, lungs, liver, intestines and kidneys in mice. We investigated the level of CREG expression during mouse embryogenesis and its distribution at 18.5 days post coitus (dpc) using immunohistochemical staining with diaminobenzidine, western blotting and reverse transcription-polymerase chain reaction. CREG expression was first detected in mouse embryos at 4.5 dpc. It was expressed at almost all stages up to 18.5 dpc. The level of CREG was found to increase gradually and was highest at 18.5 dpc. Western blotting showed that the CREG protein was expressed at higher levels in the brain, heart, intestines and kidneys than in the lungs and liver at 18.5 dpc. In 9.5 dpc embryos, CREG was expressed only in the endothelial cells of blood vessels, after the vascular lumen had formed. With advanced differentiation, vascular smooth muscle cells developed in the embryonic vascular structures; the expression of smooth muscle α-actin protein and CREG were positive and increased gradually in 10.5 dpc embryonic vessels. CREG expression in the embryonic blood vessels peaked at 15.5 dpc and was reduced slightly at 18.5 dpc. These results indicate that CREG is expressed during mouse embryogenesis and might participate in the differentiation of these organs during embryogenesis.

Functional characterization of the human-specific (type II) form of kallikrein 8, a gene involved in learning and memory

Kallikrein 8 (KLK8) is a serine protease functioning in the central nervous system, and essential in many aspects of neuronal activities. Sequence comparison and gene expression analysis among diverse primate species identified a human-specific splice form of KLK8 (type II) with preferential expression in the human brain, which may contribute to the origin of human cognition. To gain insights into the physiological and biochemical role of this novel form, we conducted functional analyses of human type II KLK8. Our results show that type II KLK8 is abundantly expressed in human embryonic stem cells and in embryo brain samples, suggesting a potential role in embryogenesis. There are dramatic expression variations in different individuals and brain regions, which is a reflection of its dynamic role in neural activities. Furthermore, the transcription start site (TSS) of KLK8 is tissue-specific, with a brain-specific TSS found in humans indicating functional specialization. Our in vitro biochemical assay shows that there is a type II-specific intermediate protein form, although the processed end-point enzymes are the same for both type I and type II KLK8, suggesting that the emergence of type II KLK8 in the human brain likely leads to functional modifications of KLK8.

The Tissue Kallikrein Family of Serine Proteases: Functional Roles in Human Disease and Potential as Clinical Biomarkers

Prostate specific antigen (PSA) or human kallikrein 3 (hK3) has long been an effective biomarker for prostate cancer. Now, other members of the tissue kallikrein (KLK) gene family are fast becoming of clinical interest due to their potential as prognostic biomarkers. particularly for hormone dependent cancers. The tissue kallikreins are serine proteases that are encoded by highly conserved multi-gene family clusters in rodents and humans. The rat and mouse loci contain 10 and 25 functional genes, respectively, while the human locus at 19q 13.4 contains 15 genes. The structural organization and size of these genes are similar across species; all genes have 5 coding exons that encode a prepro-enzyme. Although the physiological activators of these zymogens have not been described, in vitro biochemical studies show that some kallikreins can auto-activate and others can activate each other, suggesting that the kallikreins may participate in an enzymatic cascade similar to that of the coagulation cascade. These genes are expressed, to varying degrees, in a wide range of tissues suggesting a functional involvement in a diverse range of physiological and pathophysiological processes. These include roles in normal skin desquamation and psoriatic lesions, tooth development, neural plasticity, and Alzheimer's disease (AD). Of particular interest is the expression of many kallikreins in prostate, ovarian, and breast cancers where they are emerging as useful prognostic indicators of disease progression.

Neuropsin promotes oligodendrocyte death, demyelination and axonal degeneration after spinal cord injury

Previous studies indicated that the expression of neuropsin, a serine protease, is induced in mature oligodendrocytes after injury to the CNS. The pathophysiology of spinal cord injury (SCI) involves primary and secondary mechanisms, the latter contributing further to permanent losses of function. To explore the role of neuropsin after SCI, histochemical and behavioral analyses were performed in wild-type (WT) and neuropsin-deficient (neuropsin(-/-)) mice using a crush injury model, a well-characterized and consistently reproducible model of SCI. In situ hybridization revealed that neuropsin mRNA expression was induced in the spinal cord white matter from WT mice after crush SCI, peaking at day 4. Neuropsin(-/-) mice showed attenuated demyelination, oligodendrocyte death, and axonal damage after SCI. Although axonal degeneration in the corticospinal tract was obvious caudal to the lesion site in both strains of mice after SCI, the number of surviving nerve fibers caudal to the lesion was significantly larger in neuropsin(-/-) mice than WT mice. Behavioral analysis revealed that the recovery at days 10-42 was significantly improved in neuropsin(-/-) mice compared with WT mice in spite of the severe initial hindlimb impairments due to SCI in both strains. These observations suggest that neuropsin is involved in the secondary phase of the pathogenesis of SCI mediated by demyelination, oligodendrocyte death, and axonal degeneration.

Nerve injury induces the expression of EXT2, a glycosyltransferase required for heparan sulfate synthesis

Heparan sulfate proteoglycans, which bear long chains of heparan sulfate glycosaminoglycan, play significant roles during embryogenesis, including the formation of the CNS. However, their involvement in nerve regeneration has not yet been clarified. Here, we found that the mRNA expression of EXT2, one of the crucial enzymes for heparan sulfate-glycosaminoglycan synthesis, was markedly up-regulated in injured hypoglossal motor neurons after axotomy. In addition, immunohistochemical staining with an antibody specific for heparan sulfate-glycosaminoglycan chains demonstrated increased expression of heparan sulfate-glycosaminoglycan chains in the injured nucleus. Furthermore, the mRNA expressions of glypican-1 and syndecan-1, which are both well-known heparan sulfate proteoglycans, were prominently up-regulated in injured motor neurons. These results suggest that the biosynthesis of heparan sulfate chains promoted by EXT2 is activated in injured motor neurons, and that glypican-1 and syndecan-1 are potent candidates for heparan sulfate proteoglycans involved in peripheral nerve regeneration.

Involvement of neuropsin in the pathogenesis of experimental autoimmune encephalomyelitis

Inflammation, demyelination, and axonal damage of the central nervous system (CNS) are major pathological features of multiple sclerosis (MS). Proteolytic digestion of the blood-brain barrier and myelin protein by serine proteases is known to contribute to the development and progression of MS. Neuropsin, a serine protease, has a role in neuronal plasticity, and its expression has been shown to be upregulated in response to injury to the CNS. To determine the possible involvement of neuropsin in demyelinating diseases of the CNS, we examined its expression in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), a recognized animal model for MS. Neuropsin mRNA expression was induced in the spinal cord white matter of mice with EAE. Combined in situ hybridization and immunohistochemistry demonstrated that most of the cells expressing neuropsin mRNA showed immunoreactivity for CNPase, a cell-specific marker for oligodendrocytes. Mice lacking neuropsin (neuropsin-/-) exhibited an altered EAE progression characterized by delayed onset and progression of clinical symptoms as compared to wild-type mice. Neuropsin-/- mice also showed attenuated demyelination and delayed oligodendroglial death early during the course of EAE. These observations suggest that neuropsin is involved in the pathogenesis of EAE mediated by demyelination and oligodendroglial death.

Differential expression of protease M/neurosin in oligodendrocytes and their progenitors in an animal model of multiple sclerosis

To determine the possible involvement of protease M/neurosin in demyelinating diseases of the CNS, we examined its expression in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), a recognized animal model of multiple sclerosis (MS). In situ hybridization, immunohistochemistry and quantitative real-time polymerase chain reaction (PCR) demonstrated that EAE caused an increase in the expression of protease M/neurosin mRNA and its protein product throughout the white and gray matter surrounding demyelinating lesions. Combined in situ hybridization and immunohistochemistry demonstrated that most of the cells expressing protease M/neurosin mRNA within control spinal cord showed immunoreactivity for CNPase or NG2, cell-specific markers for oligodendrocytes and their progenitors, respectively. In the spinal cord from mice with EAE, the expression of protease M/neurosin mRNA in CNPase-positive cells appeared to be increased while double-labeled cells positive for protease M/neurosin mRNA and NG2 were rarely found in areas associated with demyelinating lesions. Although a prominent accumulation of inflammatory cells including T-cells was observed in the vicinity of demyelinated lesions, these cells were not associated with protease M/neurosin mRNA expression. The levels of protease M/neurosin mRNA expression were unchanged in the spleen and even decreased in the thymus during the course of EAE. These observations suggest that the differential expression of protease M/neurosin in mature oligodendrocytes and their progenitors is involved in the pathogenesis of MS and EAE.

Differential expression of neuropsin and protease M/neurosin in oligodendrocytes after injury to the spinal cord

Neuropsin and protease M/neurosin are serine proteases expressed by neurons and glial cells, and serve a variety of functions in the central nervous system (CNS). The current study demonstrates changes in the expression of these proteases following hemisection of the mouse spinal cord. Within unlesioned spinal cord, neuropsin mRNA expression was occasionally observed in the gray but not white matter, while the level of protease M/neurosin mRNA was higher in the white matter. After injury to the spinal cord, neuropsin mRNA expression was induced in the white matter in the area immediately adjacent to the lesion, peaking at 4 days post-injury and disappearing by 14 days. Enhanced expression of protease M/neurosin mRNA was observed throughout the white and gray matter surrounding the lesion, peaking at 4 days and persisting for 14 days. Neuropsin mRNA was expressed predominantly by CNPase-positive oligodendrocytes. Furthermore, most of these cells were also associated with immunoreactivity for protease M/neurosin protein. Within unlesioned spinal cord, most protease M/neurosin mRNA-expressing cells were CNPase-positive oligodendrocytes, and a substantial fraction of these cells also showed immunoreactivity for NG2, a marker for oligodendrocyte progenitors. After injury, protease M/neurosin mRNA expression within NG2-positive cells was significantly decreased, while the constitutive expression in CNPase-positive oligodendrocytes appeared to be preserved. These findings suggest that each subpopulation of oligodendrocytes based on the expression of neuropsin and protease M/neurosin has different roles in the response of the spinal cord to injury as well as in normal homeostasis.

Prolonged recovery of ultraviolet B-irradiated skin in neuropsin (KLK8)-deficient mice

BACKGROUND

Neuropsin (KLK8), a serine protease of the kallikrein family, is thought to be involved in the function of keratinocytes, i.e. migration, differentiation and desquamation. However, how neuropsin participates is still unknown.

OBJECTIVE

To observe the epidermal function of serine protease in neuropsin-deficient mice.

METHODS

We irradiated the skin of neuropsin-deficient mice with ultraviolet light to induce acute inflammation and compared the morphology with that of wild-type mice.

RESULTS

We observed a phenotypic change in the epidermis. An acute inflammatory dose of ultraviolet light induced a marked increase in neuropsin mRNA expression in the skin. The signal intensity of the mRNA expression was highest on day 2-3 after irradiation, when keratinocytes were aligned irregularly in the recovery period. Morphological comparison between neuropsin -/- and +/+ mice revealed that an irregular alignment of cells in the thickened epidermis was obvious on day 2 after irradiation in the wild-type mice, whereas it was prolonged for at least 2 days in the neuropsin-deficient mice. The stratum corneum of neuropsin-deficient mice was remarkably thicker than that of the wild-type mice at 5, 14 and 21 days after irradiation. The increase, as a response to this stimulus, in involucrin immunoreactivity, a marker for cell envelope assembly, was delayed in the mutant mice.

CONCLUSIONS

Thus, neuropsin might be involved early in the process of differentiation, such as in the assembly of the cell envelope, but not in migration and desquamation.

Decidualization induces the expression and activation of an extracellular protease neuropsin in mouse uterus

Uterine decidualization is accompanied by the remodeling of the cell-matrix and cell-cell interactions around the endometrial stromal cells to allow an appropriate invasion of trophoblasts. This remodeling is thought to require the proteolysis of extracellular matrix proteins or cell adhesion molecules; however, the molecular mechanism remains poorly understood. In this study, decidualization induced the expression and activation of an extracellular serine protease neuropsin in the mouse uterus. Although nonpregnant uteri contained little neuropsin, the protein content and enzymatic activity increased markedly and peaked at the midgestational period in pregnant uteri. Neuropsin expression and activity was also upregulated in artificially induced deciduomata but not in nondecidualized pseudopregnant uteri. Neuropsin is the first extracellular protease to show the evident induction of expression and activity by decidualization and might contribute to the remodeling of extracellular components after decidualization.

Epidermal expression of serine protease, neuropsin (KLK8) in normal and pathological skin samples

AIMS

The expression of human neuropsin (KLK8) mRNA in normal and pathological skin samples was analysed and the results compared with those for tissue plasminogen activator (tPA) mRNA.

METHODS

Northern blot and in situ hybridisation analyses of KLK8 mRNA in normal and lesional skin of patients with cutaneous diseases were performed.

RESULTS

A weak signal for KLK8 mRNA and no signal for tPA mRNA was seen in normal skin on northern blot analysis. Weak signals for KLK8 were localised to the superficial cells beneath the cornified layer in normal skin on in situ hybridisation. Psoriasis vulgaris, seborrheic keratosis, lichen planus, and squamous cell carcinoma skin samples, which show severe hyperkeratosis, displayed a high density of KLK8 mRNA on northern and in situ hybridisation analyses. The signals were localised in granular and spinous layers of lesional skin in all hyperkeratic samples, including the area surrounding the horn pearls of squamous cell carcinoma. To examine the relation between mRNA expression and terminal differentiation, the expression of KLK8 mRNA was analysed in cell cultures. When keratinisation proceeded in high calcium medium, a correlative increase in the expression of KLK8 mRNA was observed.

CONCLUSION

The results are consistent with a role for this protease in the terminal differentiation of keratinocytes.

The structure of human prokallikrein 6 reveals a novel activation mechanism for the kallikrein family

Zyme/protease M/neurosin/human kallikrein 6 (hK6) is a member of the human kallikrein family of trypsin-like serine proteinases and was originally identified as being down-regulated in metastatic breast and ovarian tumors when compared with corresponding primary tumors. Recent evidence suggests that hK6 may serve as a circulating tumor marker in ovarian cancers. In addition, it was described in the brain of Parkinson's disease and Alzheimer's disease patients, where it is implicated in amyloid precursor protein processing. It is thus a biomarker for these diseases. To examine the mechanism of activation of hK6, we have solved the structure of its proform, the first of a human kallikrein family member. The proenzyme displays a fold that exhibits chimeric features between those of trypsinogen and other family members. It lacks the characteristic "kallikrein loop" and forms the six disulfide bridges of trypsin. Pro-hK6 displays a completely closed specificity pocket and a unique conformation of the regions involved in structural rearrangements upon proteolytic cleavage activation. This points to a novel activation mechanism, which could be extrapolated to other human kallikreins.

Loss of hippocampal serine protease BSP1/neuropsin predisposes to global seizure activity

Serine proteases in the adult CNS contribute both to activity-dependent structural changes accompanying learning and to the regulation of excitotoxic cell death. Brain serine protease 1 (BSP1)/neuropsin is a trypsin-like serine protease exclusively expressed, within the CNS, in the hippocampus and associated limbic structures. To explore the role of this enzyme, we have used gene targeting to disrupt this gene in mice. Mutant mice were viable and overtly normal; they displayed normal hippocampal long-term synaptic potentiation (LTP) and exhibited no deficits in spatial navigation (water maze). Nevertheless, electrophysiological studies revealed that the hippocampus of mice lacking this specifically expressed protease possessed an increased susceptibility for hyperexcitability (polyspiking) in response to repetitive afferent stimulation. Furthermore, seizure activity on kainic acid administration was markedly increased in mutant mice and was accompanied by heightened immediate early gene (c-fos) expression throughout the brain. In view of the regional selectivity of BSP1/neuropsin brain expression, the observed phenotype may selectively reflect limbic function, further implicating the hippocampus and amygdala in controlling cortical activation. Within the hippocampus, our data suggest that BSP1/neuropsin, unlike other serine proteases, has little effect on physiological synaptic remodeling and instead plays a role in limiting neuronal hyperexcitability induced by epileptogenic insult.

Multiple roles of neurotrypsin in tissue morphogenesis and nervous system development suggested by the mRNA expression pattern

We have mapped the spatio-temporal expression of the multidomain serine protease neurotrypsin in the developing mouse by in situ hybridization. On embryonic day (E) 8, mRNA is detected in giant trophoblast cells, later in embryonic mesenchymal tissues. On E11, expression begins in Schwann cell precursors, olfactory epithelium, trigeminal ganglion, and midbrain. The floor plate shows strong expression on E12. Further prenatal development is characterized by rising neurotrypsin mRNA in sensory ganglia and motor neurons. Staining in cerebral cortex emerges around birth and culminates toward the end of the first week with a complex laminar and areal pattern. Expression in peripheral nerves and nonneural tissues vanishes soon after birth and the adult neuronal distribution is gradually established until weaning age. This developmental expression pattern suggests roles of neurotrypsin in morphogenesis of nonneural tissues, as well as in neural development, in particular in axonal target invasion, synaptogenesis, and Schwann cell differentiation.

Tissue inhibitor of matrix metalloproteinase-3 expression in the mouse uterus during implantation and artificially induced decidualization

During implantation in mice, tissue inhibitor of matrix metalloproteinases-3 is believed to play a key role in inhibiting matrix metalloproteinase activity associated with embryo invasion and tissue remodeling. The first objective of this study was to quantitatively compare the steady-state mRNA levels of tissue inhibitors of matrix metalloproteinases between segments of the mouse uterus undergoing decidualization compared to those that are not during early pregnancy plus oil-induced decidualization. Steady-state tissue inhibitor of metalloproteinase-3 mRNA levels were significantly greater in implantation compared to interimplantation areas on days 6 and 7 of pregnancy and in stimulated compared to nonstimulated uterine horns at 48 and 72 hr after artificial induction of decidualization. Steady-state tissue inhibitor of metalloproteinase-1 mRNA levels were significantly greater in implantation compared to interimplantation areas on days 5-8 of pregnancy and in stimulated compared to nonstimulated uterine horns at 24, 48, and 72 hr after oil stimulation. Therefore, the steady-state mRNA levels of tissue inhibitors of metalloproteinase-1 and -3 increased in the uterus during decidualization. The second objective of this study was to determine if transforming growth factor-beta1 influences tissue inhibitors of metalloproteinase mRNA concentrations in mouse endometrial stromal cells. As determined by Northern blot analyses, transforming growth factor beta1 significantly increased tissue inhibitors of matrix metalloproteinases-1 and -3 mRNA levels in cultured mouse endometrial stromal cells isolated from uteri sensitized for decidualization. On the other hand, interleukin-1, epidermal growth factor, and leukemia inhibitory factor had no effect. The results of this study further characterize the tissue inhibitor of metalloproteinase expression in the uterus during implantation and artificially induced decidualization and the potential control of their expression in the stroma by transforming growth factor.

Abnormalities of synapses and neurons in the hippocampus of neuropsin-deficient mice

In the present study, we produced null-mutant mice of neuropsin, an extracellular matrix serine protease, to examine the neural functions of this protein particularly in the hippocampus. Golgi-Cox impregnation and Nissl-staining revealed morphological change of cell soma in the mutant mice compared to wild-type mice. However, Golgi-Cox impregnation revealed no apparent change in the dendritic arborization and spine density. Quantitative electronmicroscopic analysis revealed that number of asymmetrical synapses were significantly decreased in the stratum radiatum, the major terminal field of Schaffer-collaterals, whereas free boutons still holding synaptic vesicles but with no synaptic specialization were increased in number in the same microscopic fields. An increased number of parvalbumin-immunoreactive cells (known as fast spiking cells) in mutant was also observed. These results strongly suggest that neuropsin is involved in connectivity of a group of CA1 synapses and consequently in the hippocampal networking.

Effects of fibronectin cleaved by neuropsin on cell adhesion and migration

Neuropsin is a serine protease cloned from the mouse hippocampus. Since neuropsin is a secreted protein which effectively cleaves fibronectin, it may affect cell adhesion or cell migration by modulating the content and/or chemical characteriscs of fibronectin in extracellular matrix (ECM). In adhesion assays, alpha5B2 cells expressing integrin alpha5beta1 bound less effectively to fibronectin teated with neuropsin than intact fibronectin. In Boyden chamber chemotaxis assays, the fibronectin-induced migration of alpha5B2 cells was not affected by neuropsin treatment. These findings suggest that neuropsin regulates the local microenvironment by modulating the interaction between cells and fibronectin in ECM.

Protease M/neurosin mRNA is expressed in mature oligodendrocytes

No proteases have been identified to be oligodendrocyte-specific though there are phenomena in which proteases may be committed. We have cloned a cDNA for mouse homologue of protease M/neurosin, serine protease, and localized its mRNA in the mouse brain. The cDNA and the deduced amino acid sequences were 66% identical to those of human protease M/neurosin. In situ hybridization histochemistry revealed that the mRNA was localized in the mature oligodendrocytes which expressed proteolipid protein mRNA. Developmentally, protease M/neurosin mRNA was expressed by oligodendrocytes 2 to 7 days after the maturation. Thus, protease M/neurosin may be important to the processes occurring after the maturation of oligodendrocytes such as myelination or turnover of the proteins in the myelin.

cDNA cloning and expression of a novel serine protease in the mouse brain

A cDNA for a novel serine protease, termed brain type granzyme K (B-GRK) was cloned from the mouse brain. The cDNA codes a protein similar to granzyme K (GRK) but completely different at the N-terminus. Genomic Southern and PCR analysis of the gene suggests B-GRK is the alternative transcription form of GRK. B-GRK and GRK have a different organ-specific expression pattern: B-GRK is expressed in the brain, while GRK is expressed in the spleen. The recombinant fusion protein was detected in the neuro2a cells transfected with a plasmid containing B-GRK sequence. The mRNA for B-GRK/GRK was detected in cerebral cortex, hippocampus and diencephalon of the mouse brain. In situ hybridization for B-GRK/GRK revealed that several regions in the forebrain and hypothalamus express the mRNA. Developmental analysis showed that in the prenatal stage, the mRNA was expressed also in pituitary and pineal body in addition to the brain.

High expression of alternative transcript of granzyme M in the mouse retina

We have isolated cDNAs to two transcripts, granzyme M and alternative granzyme M mRNA from the mouse eye. Analysis of genomic DNA revealed these transcripts were derived from alternative transcription initiations. Northern blot analysis and reverse transcription-polymerase chain reactions revealed that both transcripts were expressed in the eye, though the alternative form was the major type. In situ hybridization studies demonstrated that alternative granzyme M mRNA localized exclusively in the photoreceptor cells in the retina and expressed only after the opening of the eye, suggesting that these transcripts are related to the maintenance of the retinal structure or functions of matured photoreceptor cells rather than the development or differentiation of retinal cells.

A novel form of human neuropsin, a brain-related serine protease, is generated by alternative splicing and is expressed preferentially in human adult brain

We have cloned cDNAs encoding two isoforms of a human novel serine protease. They encoded sequences of 260 and 305 amino acids, and both showed significant homology to mouse neuropsin. Mouse neuropsin has been reported to be involved in hippocampal plasticity, therefore we designated the proteins as type 1 and type 2 neuropsin, respectively. The amino acid sequences of the two types of human neuropsin were identical, except that type 2 carried an insert of 45 amino acids at the C-terminus of the leader sequence. The essential three amino acids in the active site triad, His, Asp, and Ser, and the single putative N-glycosylation site were conserved in human and mouse neuropsin. Sequence analysis of the 946 bp genomic DNA spanning the region encoding the insertion sequence revealed that two isoforms were generated in human brain by alternative splicing. However, the mouse genomic sequence did not conserve the 3' acceptor consensus sequence at the corresponding position, suggesting that type 2 neuropsin was a species-specific splice variant. When the open reading frames of human neuropsin were expressed in insect cells, both types of neuropsin were detected in the conditioned media by western blot analysis using anti-human neuropsin serum. Northern blot hybridization and reverse transcription-polymerase chain reaction showed predominant expression of type 1 neuropsin in pancreas. Type 2 neuropsin was preferentially expressed in human adult brain and hippocampus, although both types were expressed in fetal brain and placenta in comparable amounts. Dot blot hybridization showed that neuropsin was expressed in various regions of adult brain, including the hippocampus and cerebral cortex, and also in various fetal tissues. These results suggest that human type 2 neuropsin may be important to the adult brain plasticity, although both types may be necessary for the development of the nervous system.

cDNA cloning and expression of a novel serine protease, TLSP

A cDNA for a putative novel serine protease, TLSP, was cloned from human hippocampus cDNA with polymerase chain reaction based strategies. The putative amino acid sequence of TLSP is similar to the trypsin-type serine proteases. TLSP mRNA is expressed in keratinocytes. Overexpressed TLSP protein in neuro2a cells was detected in culture medium.

Sequence analysis and expression of human neuropsin cDNA and gene

Neuropsin is a serine protease which is thought to function in a variety of tissues including the brain and skin. This protease has been shown to have important roles in neural plasticity in mice. Here we have cloned a cDNA and analyzed the gene for human neuropsin by polymerase chain reaction-based strategies. The cDNA had 72% identity to mouse neuropsin. The deduced amino acid sequence showed 72% identity to mouse neuropsin. Key amino acid residues for the enzyme activity and all cysteine residues were conserved between human and mouse neuropsin. The gene for human neuropsin had six exons and five introns, and the gene organization is similar to trypsin-type serine proteases. The mRNA was expressed in primary cultures of keratinocytes.

Expression of neuropsin in the keratinizing epithelial tissue-immunohistochemical analysis of wild-type and nude mice

Neuropsin is a trypsin-type serine protease that was first cloned from the mouse brain as a factor related to neural plasticity. Subsequent in situ hybridization histochemical analysis indicated a broad localization of its mRNA throughout the whole body, although the details remain obscure. In this study, we showed that neuropsin immunoreactivity is localized in the keratinized stratified epithelia of the mouse epidermis, hair, tongue, palate, nasal cavity, pharynges, esophagus, and forestomach. In the skin and mucous membranes, neuropsin immunoreactivity was found in the stratum spinosum and the stratum granulosum. The immunoreactivity in the former sublayer was mainly present in the cytoplasm, but that in the latter sublayer was exclusively present in the intercellular space or on the outer surface of the cell membrane and thus exhibited a lamellar-like peripheral distribution. During development, the appearance of neuropsin immunoreactivity in the various epithelia was found at embryonic days 14.5-15.5, prior to formation of the stratum corneum. More extensive expression of neuropsin immunoreactivity was found in the nude mouse skin and mucous membranes than in wild-type mice. Because the nude mouse is characterized by genetic impairment of keratinization, such abnormal neuropsin expression might be caused or affected by this impairment. Therefore, neuropsin, an extracellular serine protease, is suggested to be involved in keratinization in the stratified epithelia.

Characterization of recombinant and brain neuropsin, a plasticity-related serine protease

Activity-dependent changes in neuropsin gene expression in the hippocampus implies an involvement of neuropsin in neural plasticity. Since the deduced amino acid sequence of the gene contained the complete triplet (His-Asp-Ser) of the serine protease domain, the protein was postulated to have proteolytic activity. Recombinant full-length neuropsin produced in the baculovirus/insect cell system was enzymatically inactive but was readily converted to active enzyme by endoprotease processing. The activational processing of prototype neuropsin involved the specific cleavage of the Lys32-Ile33 bond near its N terminus. Native neuropsin that was purified with a purity of 1,100-fold from mouse brain had enzymatic characteristics identical to those of active-type recombinant neuropsin. Both brain and recombinant neuropsin had amidolytic activities cleaving Arg-X and Lys-X bonds in the synthetic chromogenic substrates, and the highest specific activity was found against Boc-Val-Pro-Arg-4-methylcoumaryl-7-amide. The active-type recombinant neuropsin effectively cleaved fibronectin, an extracellular matrix protein. Taken together, these results indicate that this protease, which is enzymatically novel, has significant limbic effects by changing the extracellular matrix environment.