Deterioration after Liver Transplantation and Transthyretin Stabilizer Administration in a Patient with ATTRv Amyloidosis with a Leu58Arg (p.Leu78Arg) TTR Variant.

We herein report a 44-year-old Japanese man with hereditary transthyretin amyloidosis (ATTRv amyloidosis) harboring the variant Leu58Arg (p.Leu78Arg) in TTR in whom we conducted an observational study with liver transplantation (LT) and transthyretin (TTR) stabilizers (tafamidis and diflunisal) for 9 years. This patient showed gradual deterioration of sensory, motor, and autonomic neuropathy symptoms after LT. Furthermore, cardiac amyloidosis gradually developed. Although the present case showed deterioration of the symptoms after disease-modifying treatments, LT might be suitable in patients with the same variant if they are young and in good condition due to a long survival after LT.

Establishment of a human hepatocellular cell line capable of maintaining long-term replication of hepatitis B virus.

Hepatitis B virus (HBV) is a virus whose replication cycle cannot be completely reproduced using cultured cell lines. Here, we report an engineered cell line capable of supporting the complete HBV life cycle. We generated HepG2 cells over-expressing the HBV entry receptor human NTCP (sodium taurocholate cotransporting polypeptide), and defective in RIG-I (retinoic acid-inducible gene-I)-like receptor signaling, by knocking down the IPS-1 (IFNß-promoter stimulator-1) adaptor molecule. The resultant NtG20.i7 cells were susceptible to HBV, and its replication was detectable at 14 days post-infection and persisted for at least 35 days with a gradual increase of HBV core expression. The cells produced infectious HBV in the culture supernatant, and the addition of preS1 peptide myr47-WT, which blocks HBV entry, impaired the persistence of the infection. These findings suggest that the persistence of the infection was maintained by continuous release of infectious HBV virions and their re-infection. This system is useful for expanding our basic understanding of the HBV replication cycle and for screening of anti-HBV chemicals.

Multiple Roles of the Cytoplasmic Domain of Herpes Simplex Virus 1 Envelope Glycoprotein D in Infected Cells.

Herpes simplex virus 1 (HSV-1) envelope glycoprotein D (gD) plays an essential role in viral entry. The functional regions of gD responsible for viral entry have been mapped to its extracellular domain, whereas the gD cytoplasmic domain plays no obvious role in viral entry. Thus far, the role(s) of the gD cytoplasmic domain in HSV-1 replication has remained to be elucidated. In this study, we show that ectopic expression of gD induces microvillus-like tubular structures at the plasma membrane which resemble the reported projection structures of the plasma membrane induced in HSV-1-infected cells. Mutations in the arginine cluster (residues 365 to 367) in the gD cytoplasmic domain greatly reduced gD-induced plasma membrane remodeling. In agreement with this, the mutations in the arginine cluster in the gD cytoplasmic domain reduced the number of microvillus-like tubular structures at the plasma membrane in HSV-1-infected cells. In addition, the mutations produced an accumulation of unenveloped nucleocapsids in the cytoplasm and reduced viral replication and cell-cell spread. These results suggest that the arginine cluster in the gD cytoplasmic domain is required for the efficient induction of plasma membrane projections and viral final envelopment, and these functions of the gD domain may lead to efficient viral replication and cell-cell spread. IMPORTANCE: The cytoplasmic domain of HSV-1 gD, an envelope glycoprotein essential for viral entry, was reported to promote viral replication and cell-cell spread, but the role(s) of the domain during HSV-1 infection has remained unknown. In this study, we clarify two functions of the arginine cluster in the HSV-1 gD cytoplasmic domain, both of which require host cell membrane remodeling, i.e., the formation of microvillus-like projections at the plasma membrane and viral final envelopment in HSV-1-infected cells. We also show that the gD arginine cluster is required for efficient HSV-1 replication and cell-cell spread. This is the first report clarifying not only the functions of the gD cytoplasmic domain but also identifying the gD arginine cluster to be the HSV-1 factor responsible for the induction of plasma membrane projections in HSV-1-infected cells. Our results elucidate some of the functions of this multifunctional envelope glycoprotein during HSV-1 infection.

Herpes simplex virus 1 UL47 interacts with viral nuclear egress factors UL31, UL34, and Us3 and regulates viral nuclear egress.

UNLABELLED: Herpesviruses have evolved a unique mechanism for nuclear egress of nascent progeny nucleocapsids: the nucleocapsids bud through the inner nuclear membrane into the perinuclear space between the inner and outer nuclear membranes (primary envelopment), and enveloped nucleocapsids then fuse with the outer nuclear membrane to release nucleocapsids into the cytoplasm (de-envelopment). We have shown that the herpes simplex virus 1 (HSV-1) major virion structural protein UL47 (or VP13/VP14) is a novel regulator for HSV-1 nuclear egress. In particular, we demonstrated the following: (i) UL47 formed a complex(es) with HSV-1 proteins UL34, UL31, and/or Us3, which have all been reported to be critical for viral nuclear egress, and these viral proteins colocalized at the nuclear membrane in HSV-1-infected cells; (ii) the UL47-null mutation considerably reduced primary enveloped virions in the perinuclear space although capsids accumulated in the nucleus; and (iii) UL47 was detected in primary enveloped virions in the perinuclear space by immunoelectron microscopy. These results suggested that UL47 promoted HSV-1 primary envelopment, probably by interacting with the critical HSV-1 regulators for viral nuclear egress and by modulating their functions. IMPORTANCE: Like other herpesviruses, herpes simplex virus 1 (HSV-1) has evolved a vesicle-mediated nucleocytoplasmic transport mechanism for nuclear egress of nascent progeny nucleocapsids. Although previous reports identified and characterized several HSV-1 and cellular proteins involved in viral nuclear egress, complete details of HSV-1 nuclear egress remain to be elucidated. In this study, we have presented data suggesting (i) that the major HSV-1 virion structural protein UL47 (or VP13/VP14) formed a complex with known viral regulatory proteins critical for viral nuclear egress and (ii) that UL47 played a regulatory role in HSV-1 primary envelopment. Thus, we identified UL47 as a novel regulator for HSV-1 nuclear egress.

Chronic pain-induced emotional dysfunction is associated with astrogliosis due to cortical delta-opioid receptor dysfunction.

It has been widely recognized that chronic pain could cause physiological changes at supraspinal levels. The delta-opioidergic system is involved in antinociception, emotionality, immune response and neuron-glia communication. In this study, we show that mice with chronic pain exhibit anxiety-like behavior and an increase of astrocytes in the cingulate cortex due to the dysfunction of cortical delta-opioid receptor systems. Using neural stem cells cultured from the mouse embryonic forebrain, astrocyte differentiation was clearly observed following long-term exposure to the selective delta-opioid receptor antagonist, naltrindole. We also found that micro-injection of either activated astrocyte or astrocyte-conditioned medium into the cingulate cortex of mice aggravated the expression of anxiety-like behavior. Our results indicate that the chronic pain process promotes astrogliosis in the cingulate cortex through the dysfunction of cortical delta-opioid receptors. This phenomenon may lead to emotional disorders including aggravated anxiety under chronic pain-like state.