Recognition of virus infections by pattern recognition receptors (PRRs),

Imino sugars, such as N-butyl-deoxynojirimycin and N-nonyl-deoxynojirimycin (NNDNJ), are glucose analogues that selectively inhibit cellular ␣-glucosidase I and II in the endoplasmic reticulum and exhibit antiviral activities against many types of enveloped viruses. Although these molecules have broad-spectrum antiviral activity, their development has been limited by a lack of efficacy and/or selectivity. We have previously reported that a DNJ derivative with a hydroxylated cyclohexyl side chain, called OSL-95II, has an antiviral efficacy similar to that of NNDNJ but significantly less toxicity. Building upon this observation, a family of imino sugar derivatives containing an oxygenated side chain and terminally restricted ring structures were synthesized and shown to have low cytotoxicity and superior antiviral activity against members of the Flaviviridae family, including bovine viral diarrhea virus, dengue virus (DENV), and West Nile virus. Of particular interest is that several of these novel imino sugar derivatives, such as PBDNJ0801, PBDNJ0803, and PBDNJ0804, potently inhibit DENV infection in vitro, with 90% effective concentration values at submicromolar concentrations and selectivity indices greater than 800. Therefore, these compounds represent the best in their class and may offer realistic candidates for the development of antiviral therapeutics against human DENV infections.Imino sugars are glucose mimetics with a nitrogen atom in place of a ring oxygen (11). Some imino sugar derivatives, such as deoxynojirimycin (DNJ), competitively inhibit cellular endoplasmic reticulum (ER) ␣-glucosidases I and II (11). ER ␣-glucosidases remove glucose residues from the high-mannose N-linked glycans attached to nascent glycoproteins (16), which is critical for the subsequent interaction between the glycoproteins and ER chaperones calnexin and calreticulin. It has been shown that such interaction is required for the correct folding and sorting of some but not all glycoproteins (11,16). Thus, it has been reasoned that inhibition of ␣-glucosidases might disturb the maturation, secretion, and function of viral envelope glycoproteins and, as a result, inhibit viral particle assembly and/or secretion of enveloped viruses. Consistent with this notion is the observation that for many types of enveloped viruses, including hepatitis B virus, human immunodeficiency virus (HIV), herpes simplex virus type 1, influenza viruses, parainfluenza virus, and measles virus, as well as several members of the Flaviviridae family, such as bovine viral diarrhea virus (BVDV), dengue virus (DENV), West Nile virus (WNV), Japanese encephalitis virus, and hepatitis C virus (HCV), virion production can be inhibited by ␣-glucosidase inhibitors, such as DNJ and its derivatives (3,5,6,9,14,17,22,30,31,34). For some viruses, virion particles produced under treatment with glucosidase inhibitors carried unprocessed (or altered) glycans on their envelope glycoproteins and were reduced in infectivity (17, 26). Moreover, it was shown that a DNJ derivat...

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MAP1B is a major cytoskeletal protein in growing axons and is strongly regulated during brain development. The present studies compare the expression of MAP1B mRNA, the protein, and its phosphorylated isoform in spinal cord and dorsal root ganglia (DRGs) with brain. In spinal cord and brain, MAP1B mRNA levels were highest in early stages of development, decreased several fold during postnatal development, and remained low in adults. In contrast, there were no significant changes of MAP1B mRNA levels during development of DRG and they remained high in adults. The levels of MAP1B protein decreased in brain and spinal cord in parallel with the changes of their mRNA. The protein levels in DRG remained relatively high but declined in the sciatic nerve. Phosphorylated MAP1B was expressed in high levels during the early stages of development in brain, spinal cord, and sciatic nerve and decreased rapidly to undetectable levels postnatally except for sciatic nerve where it remained detectable. Immunohistochemical analysis showed that phosphorylated MAP1B was absent from DRG cell bodies at all stages but was present in axons of DRG and motor neurons in both spinal cord and sciatic nerve. Immunostaining also confirmed Western blot analysis indicating that MAP1B was initially abundant within the spinal cord but was at later stages present only in motor neurons and the central processes of DRG neurons. These results reflect differential distribution of MAP1B isoforms at different stages of development and in different regions of the nervous system.

Cytoskeletal proteins are axonally transported with slow components a and b (SCa and SCb). In peripheral nerves, the transport velocity of SCa, which includes neurofilaments and tubulin, is 1-2 mm/d, whereas SCb, which includes actin, tubulin, and numerous soluble proteins, moves as a heterogeneous wave at 2-4 mm/d. We have shown that two isoforms of microtubule-associated protein 1B (MAP1B), which can be separated on SDS polyacrylamide gels on the basis of differences in their phosphorylation states (band I and band II), were transported at two different rates. All of band I MAP1B moved as a coherent wave at a velocity of 7-9 mm/d, distinct from slow axonal transport components SCa and SCb. Several other proteins were detected within the component that moved at the velocity of 7-9 mm/d, including the leading wave of tubulin and actin. The properties of this component define a distinct fraction of the slow axonal transport that we suggest to term slow component c (SCc). The relatively fast transport of the phosphorylated MAP1B isoform at 7-9 mm/d may account for the high concentration of phosphorylated MAP1B in the distal end of growing axons. In contrast to band I MAP1B, the transport profile of band II was complex and contained components moving with SCa and SCb and a leading edge at SCc. Thus, MAP1B isoforms in different phosphorylation states move with distinct components of slow axonal transport, possibly because of differences in their abilities to associate with other proteins.