Unraveling the mechanism of malancao in treating ulcerative colitis: A multi-omics approach.

BACKGROUND: Malancao (MLC) is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis (UC). Nevertheless, the precise molecular mechanisms underlying its efficacy remain elusive. This study leveraged ultra-high-performance liquid chromatography coupled with exactive mass spectrometry (UHPLC-QE-MS), network pharmacology, molecular docking (MD), and gene microarray analysis to discern the bioactive constituents and the potential mechanism of action of MLC in UC management. AIM: To determine the ingredients related to MLC for treatment of UC using multiple databases to obtain potential targets for fishing. METHODS: This research employs UHPLC-QE-MS for the identification of bioactive compounds present in MLC plant samples. Furthermore, the study integrates the identified MLC compound-related targets with publicly available databases to elucidate common drug disease targets. Additionally, the R programming language is utilized to predict the central targets and molecular pathways that MLC may impact in the treatment of UC. Finally, MD are conducted using AutoDock Vina software to assess the affinity of bioactive components to the main targets and confirm their therapeutic potential. RESULTS: Firstly, through a comprehensive analysis of UHPLC-QE-MS data and public database resources, we identified 146 drug-disease cross targets related to 11 bioactive components. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted that common disease drug targets are primarily involved in oxidative stress management, lipid metabolism, atherosclerosis, and other processes. They also affect AGE-RAGE and apoptosis signaling pathways. Secondly, by analyzing the differences in diseases, we identified key research targets. These core targets are related to 11 active substances, including active ingredients such as quercetin and luteolin. Finally, MD analysis revealed the stability of compound-protein binding, particularly between JUN-Luteolin, JUN-Quercetin, HSP90AA1-Wogonin, and HSP90AA1-Rhein. Therefore, this suggests that MLC may help alleviate intestinal inflammation in UC, restore abnormal lipid accumulation, and regulate the expression levels of core proteins in the intestine. CONCLUSION: The utilization of MLC has demonstrated notable therapeutic efficacy in the management of UC by means of the compound target interaction pathway. The amalgamation of botanical resources, metabolomics, natural products, MD, and gene chip technology presents a propitious methodology for investigating therapeutic targets of herbal medicines and discerning novel bioactive constituents.

Intranasal neomycin evokes broad-spectrum antiviral immunity in the upper respiratory tract.

Respiratory virus infections in humans cause a broad-spectrum of diseases that result in substantial morbidity and mortality annually worldwide. To reduce the global burden of respiratory viral diseases, preventative and therapeutic interventions that are accessible and effective are urgently needed, especially in countries that are disproportionately affected. Repurposing generic medicine has the potential to bring new treatments for infectious diseases to patients efficiently and equitably. In this study, we found that intranasal delivery of neomycin, a generic aminoglycoside antibiotic, induces the expression of interferon-stimulated genes (ISGs) in the nasal mucosa that is independent of the commensal microbiota. Prophylactic or therapeutic administration of neomycin provided significant protection against upper respiratory infection and lethal disease in a mouse model of COVID-19. Furthermore, neomycin treatment protected Mx1 congenic mice from upper and lower respiratory infections with a highly virulent strain of influenza A virus. In Syrian hamsters, neomycin treatment potently mitigated contact transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In healthy humans, intranasal application of neomycin-containing Neosporin ointment was well tolerated and effective at inducing ISG expression in the nose in a subset of participants. These findings suggest that neomycin has the potential to be harnessed as a host-directed antiviral strategy for the prevention and treatment of respiratory viral infections.

Compartmentalized ocular lymphatic system mediates eye-brain immunity.

The eye, an anatomical extension of the central nervous system (CNS), exhibits many molecular and cellular parallels to the brain. Emerging research demonstrates that changes in the brain are often reflected in the eye, particularly in the retina1. Still, the possibility of an immunological nexus between the posterior eye and the rest of the CNS tissues remains unexplored. Here, studying immune responses to herpes simplex virus in the brain, we observed that intravitreal immunization protects mice against intracranial viral challenge. This protection extended to bacteria and even tumours, allowing therapeutic immune responses against glioblastoma through intravitreal immunization. We further show that the anterior and posterior compartments of the eye have distinct lymphatic drainage systems, with the latter draining to the deep cervical lymph nodes through lymphatic vasculature in the optic nerve sheath. This posterior lymphatic drainage, like that of meningeal lymphatics, could be modulated by the lymphatic stimulator VEGFC. Conversely, we show that inhibition of lymphatic signalling on the optic nerve could overcome a major limitation in gene therapy by diminishing the immune response to adeno-associated virus and ensuring continued efficacy after multiple doses. These results reveal a shared lymphatic circuit able to mount a unified immune response between the posterior eye and the brain, highlighting an understudied immunological feature of the eye and opening up the potential for new therapeutic strategies in ocular and CNS diseases.

Unadjuvanted intranasal spike vaccine elicits protective mucosal immunity against sarbecoviruses.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has highlighted the need for vaccines that not only prevent disease but also prevent transmission. Parenteral vaccines induce robust systemic immunity but poor immunity at the respiratory mucosa. We developed a vaccine strategy that we call "prime and spike," which leverages existing immunity generated by primary vaccination (prime) to elicit mucosal immune memory within the respiratory tract by using unadjuvanted intranasal spike boosters (spike). We show that prime and spike induces robust resident memory B and T cell responses, induces immunoglobulin A at the respiratory mucosa, boosts systemic immunity, and completely protects mice with partial immunity from lethal SARS-CoV-2 infection. Using divergent spike proteins, prime and spike enables the induction of cross-reactive immunity against sarbecoviruses.

Unadjuvanted intranasal spike vaccine booster elicits robust protective mucosal immunity against sarbecoviruses.

As the SARS-CoV-2 pandemic enters its third year, vaccines that not only prevent disease, but also prevent transmission are needed to help reduce global disease burden. Currently approved parenteral vaccines induce robust systemic immunity, but poor immunity at the respiratory mucosa. Here we describe the development of a novel vaccine strategy, Prime and Spike, based on unadjuvanted intranasal spike boosting that leverages existing immunity generated by primary vaccination to elicit mucosal immune memory within the respiratory tract. We show that Prime and Spike induces robust T resident memory cells, B resident memory cells and IgA at the respiratory mucosa, boosts systemic immunity, and completely protects mice with partial immunity from lethal SARS-CoV-2 infection. Using divergent spike proteins, Prime and Spike enables induction of cross-reactive immunity against sarbecoviruses without invoking original antigenic sin. ONE-SENTENCE SUMMARY: Broad sarbecovirus protective mucosal immunity is generated by unadjuvanted intranasal spike boost in preclinical model.

A stem-loop RNA RIG-I agonist protects against acute and chronic SARS-CoV-2 infection in mice.

As SARS-CoV-2 continues to cause morbidity and mortality around the world, there is an urgent need for the development of effective medical countermeasures. Here, we assessed the antiviral capacity of a minimal RIG-I agonist, stem-loop RNA 14 (SLR14), in viral control, disease prevention, post-infection therapy, and cross-variant protection in mouse models of SARS-CoV-2 infection. A single dose of SLR14 prevented viral infection in the lower respiratory tract and development of severe disease in a type I interferon (IFN-I)-dependent manner. SLR14 demonstrated remarkable prophylactic protective capacity against lethal SARS-CoV-2 infection and retained considerable efficacy as a therapeutic agent. In immunodeficient mice carrying chronic SARS-CoV-2 infection, SLR14 elicited near-sterilizing innate immunity in the absence of the adaptive immune system. In the context of infection with variants of concern (VOCs), SLR14 conferred broad protection against emerging VOCs. These findings demonstrate the therapeutic potential of SLR14 as a host-directed, broad-spectrum antiviral for early post-exposure treatment and treatment of chronically infected immunosuppressed patients.

Analysis of atmospheric SO2 in Sichuan-Chongqing region based on OMI data.

The Sichuan-Chongqing region is the leader and growth pole of economic development in western China. With the rapid development of economy and unique geographical environment, high concentration of sulfur dioxide air pollution has existed for a long time in Sichuan-Chongqing area. Based on 10 years of remote sensing data, this paper studies the temporal and spatial distribution characteristics, stability, and influencing factors of sulfur dioxide in this area. Based on potential sources, the impact of surrounding areas on sulfur dioxide in Sichuan and Chongqing is analyzed. The results shows that the spatial distribution of sulfur dioxide in the Sichuan-Chongqing region is higher in the southeast and lower in the west. The Midwest region has low fluctuation and good stability. The time distribution shows obvious seasonal regularity. The concentration of sulfur dioxide is affected by socio-economic factors and natural factors. In this study, it is found that the distribution of sulfur dioxide is closely related to PM2.5, which provides an important reference for the comprehensive management of air pollution. The OMI data effectively reflects the distribution and change of atmospheric sulfur dioxide in the Sichuan-Chongqing region, and provides certain ideas for air pollution control in the Sichuan-Chongqing region and other regions in China.

A stem-loop RNA RIG-I agonist confers prophylactic and therapeutic protection against acute and chronic SARS-CoV-2 infection in mice.

As SARS-CoV-2 continues to cause morbidity and mortality around the world, there is an urgent need for the development of effective medical countermeasures. Here, we assessed the antiviral capacity of a minimal RIG-I agonist, stem-loop RNA 14 (SLR14), in viral control, disease prevention, post-infection therapy, and cross-variant protection in mouse models of SARS-CoV-2 infection. A single dose of SLR14 prevented viral replication in the lower respiratory tract and development of severe disease in a type I interferon (IFN-I) dependent manner. SLR14 demonstrated remarkable protective capacity against lethal SARS-CoV-2 infection when used prophylactically and retained considerable efficacy as a therapeutic agent. In immunodeficient mice carrying chronic SARS-CoV-2 infection, SLR14 elicited near-sterilizing innate immunity by inducing IFN-I responses in the absence of the adaptive immune system. In the context of infection with variants of concern (VOC), SLR14 conferred broad protection and uncovered an IFN-I resistance gradient across emerging VOC. These findings demonstrate the therapeutic potential of SLR14 as a host-directed, broad-spectrum antiviral for early post-exposure treatment and for treatment of chronically infected immunosuppressed patients.

Study on the variation characteristics of tropospheric ozone in Northeast China.

The goal of this study was to understand the current status of ozone pollution in Northeast China and to distinguish the main influencing factors of ozone, in order to provide a scientific basis for the future prevention and control of ozone in this region. In this study, the Ozone Monitoring Instrument data product was used as the source data, and the pixel space analysis method and grey correlation analysis method were utilized to examine the tropospheric ozone column concentration in Northeast China from 2010 to 2018. The results revealed that the ozone column concentration in Northeast China was relatively high compared to other parts of the country. The high-value areas were primarily distributed in Tahe County, Heihe City, Hegang City, and Qiqihar City. The temporal variation of the ozone column concentration in Northeast China exhibited an obvious periodicity of 9 years, and its interannual change displayed a downward trend. The maximum value occurred in 2010, and the minimum value was found in 2016. The seasonal changes manifested a relative trend of spring > winter > summer > autumn, which was contrary to the research results for other parts of China, which showed a summer maximum. Among the influencing factors, atmospheric pressure, relative humidity, sunshine hours, GDP, and primary and secondary industries exhibited the closest relationships with ozone. The high concentration of ozone in Northeast China was determined to result from the superimposed effects of long-distance atmospheric transport and anthropogenic emissions.

Endogenous Retroviruses Provide Protection Against Vaginal HSV-2 Disease.

Endogenous retroviruses (ERVs) are genomic sequences that originated from retroviruses and are present in most eukaryotic genomes. Both beneficial and detrimental functions are attributed to ERVs, but whether ERVs contribute to antiviral immunity is not well understood. Here, we used herpes simplex virus type 2 (HSV-2) infection as a model and found that Toll-like receptor 7 (Tlr7-/-) deficient mice that have high systemic levels of infectious ERVs are protected from intravaginal HSV-2 infection and disease, compared to wildtype C57BL/6 mice. We deleted the endogenous ecotropic murine leukemia virus (Emv2) locus on the Tlr7-/- background (Emv2-/-Tlr7-/-) and found that Emv2-/-Tlr7-/- mice lose protection against HSV-2 infection. Intravaginal application of purified ERVs from Tlr7-/- mice prior to HSV-2 infection delays disease in both wildtype and highly susceptible interferon-alpha receptor-deficient (Ifnar1-/-) mice. However, intravaginal ERV treatment did not protect Emv2-/-Tlr7-/- mice from HSV-2 disease, suggesting that the protective mechanism mediated by exogenous ERV treatment may differ from that of constitutively and systemically expressed ERVs in Tlr7-/- mice. We did not observe enhanced type I interferon (IFN-I) signaling in the vaginal tissues from Tlr7-/- mice, and instead found enrichment in genes associated with extracellular matrix organization. Together, our results revealed that constitutive and/or systemic expression of ERVs protect mice against vaginal HSV-2 infection and delay disease.

Mouse model of SARS-CoV-2 reveals inflammatory role of type I interferon signaling.

Severe acute respiratory syndrome-coronavirus 2 (SARS-Cov-2) has caused over 13,000,000 cases of coronavirus disease (COVID-19) with a significant fatality rate. Laboratory mice have been the stalwart of therapeutic and vaccine development; however, they do not support infection by SARS-CoV-2 due to the virus's inability to use the mouse orthologue of its human entry receptor angiotensin-converting enzyme 2 (hACE2). While hACE2 transgenic mice support infection and pathogenesis, these mice are currently limited in availability and are restricted to a single genetic background. Here we report the development of a mouse model of SARS-CoV-2 based on adeno-associated virus (AAV)-mediated expression of hACE2. These mice support viral replication and exhibit pathological findings found in COVID-19 patients. Moreover, we show that type I interferons do not control SARS-CoV-2 replication in vivo but are significant drivers of pathological responses. Thus, the AAV-hACE2 mouse model enables rapid deployment for in-depth analysis following robust SARS-CoV-2 infection with authentic patient-derived virus in mice of diverse genetic backgrounds.

Mouse model of SARS-CoV-2 reveals inflammatory role of type I interferon signaling.

Severe Acute Respiratory Syndrome- Coronavirus 2 (SARS-Cov-2) has caused over 5,000,000 cases of Coronavirus disease (COVID-19) with significant fatality rate.1-3 Due to the urgency of this global pandemic, numerous therapeutic and vaccine trials have begun without customary safety and efficacy studies.4 Laboratory mice have been the stalwart of these types of studies; however, they do not support infection by SARS-CoV-2 due to the inability of its spike (S) protein to engage the mouse ortholog of its human entry receptor angiotensin-converting enzyme 2 (hACE2). While hACE2 transgenic mice support infection and pathogenesis,5 these mice are currently limited in availability and are restricted to a single genetic background. Here we report the development of a mouse model of SARS-CoV-2 based on adeno associated virus (AAV)-mediated expression of hACE2. These mice support viral replication and antibody production and exhibit pathologic findings found in COVID-19 patients as well as non-human primate models. Moreover, we show that type I interferons are unable to control SARS-CoV2 replication and drive pathologic responses. Thus, the hACE2-AAV mouse model enables rapid deployment for in-depth analysis following robust SARS-CoV-2 infection with authentic patient-derived virus in mice of diverse genetic backgrounds. This represents a much-needed platform for rapidly testing prophylactic and therapeutic strategies to combat COVID-19.

Mouse model of SARS-CoV-2 reveals inflammatory role of type I interferon signaling.

Severe Acute Respiratory Syndrome- Coronavirus 2 (SARS-Cov-2) has caused over 5,000,000 cases of Coronavirus disease (COVID-19) with significant fatality rate.1-3 Due to the urgency of this global pandemic, numerous therapeutic and vaccine trials have begun without customary safety and efficacy studies.4 Laboratory mice have been the stalwart of these types of studies; however, they do not support infection by SARS-CoV-2 due to the inability of its spike (S) protein to engage the mouse ortholog of its human entry receptor angiotensin-converting enzyme 2 (hACE2). While hACE2 transgenic mice support infection and pathogenesis,5 these mice are currently limited in availability and are restricted to a single genetic background. Here we report the development of a mouse model of SARS-CoV-2 based on adeno associated virus (AAV)-mediated expression of hACE2. These mice support viral replication and antibody production and exhibit pathologic findings found in COVID-19 patients as well as non-human primate models. Moreover, we show that type I interferons are unable to control SARS-CoV2 replication and drive pathologic responses. Thus, the hACE2-AAV mouse model enables rapid deployment for in-depth analysis following robust SARS-CoV-2 infection with authentic patient-derived virus in mice of diverse genetic backgrounds. This represents a much-needed platform for rapidly testing prophylactic and therapeutic strategies to combat COVID-19.

VEGF-C-driven lymphatic drainage enables immunosurveillance of brain tumours.

Immune surveillance against pathogens and tumours in the central nervous system is thought to be limited owing to the lack of lymphatic drainage. However, the characterization of the meningeal lymphatic network has shed light on previously unappreciated ways that an immune response can be elicited to antigens that are expressed in the brain1-3. Despite progress in our understanding of the development and structure of the meningeal lymphatic system, the contribution of this network in evoking a protective antigen-specific immune response in the brain remains unclear. Here, using a mouse model of glioblastoma, we show that the meningeal lymphatic vasculature can be manipulated to mount better immune responses against brain tumours. The immunity that is mediated by CD8 T cells to the glioblastoma antigen is very limited when the tumour is confined to the central nervous system, resulting in uncontrolled tumour growth. However, ectopic expression of vascular endothelial growth factor C (VEGF-C) promotes enhanced priming of CD8 T cells in the draining deep cervical lymph nodes, migration of CD8 T cells into the tumour, rapid clearance of the glioblastoma and a long-lasting antitumour memory response. Furthermore, transfection of an mRNA construct that expresses VEGF-C works synergistically with checkpoint blockade therapy to eradicate existing glioblastoma. These results reveal the capacity of VEGF-C to promote immune surveillance of tumours, and suggest a new therapeutic approach to treat brain tumours.

Human APOBEC3G Prevents Emergence of Infectious Endogenous Retrovirus in Mice.

Endogenous retroviruses (ERV) are found throughout vertebrate genomes, and failure to silence their activation can have deleterious consequences on the host. Mutation and subsequent disruption of ERV loci is therefore an indispensable component of the cell-intrinsic defenses that maintain the integrity of the host genome. Abundant in vitro and in silico evidence have revealed that APOBEC3 cytidine-deaminases, including human APOBEC3G (hA3G), can potently restrict retrotransposition; yet, in vivo data demonstrating such activity is lacking, since no replication-competent human ERV have been identified. In mice deficient for Toll-like receptor 7 (TLR7), transcribed ERV loci can recombine and generate infectious ERV. In this study, we show that ectopic expression of hA3G can prevent the emergence of replication-competent, infectious ERV in Tlr7-/- mice. Mice encode one copy of Apobec3 in their genome. ERV reactivation in Tlr7-/- mice was comparable in the presence or absence of Apobec3 In contrast, expression of a human APOBEC3G transgene abrogated emergence of infectious ERV in the Tlr7-/- background. No ERV RNA was detected in the plasma of hA3G+Apobec3-/-Tlr7-/- mice, and infectious ERV virions could not be amplified through coculture with permissive cells. These data reveal that hA3G can potently restrict active ERV in vivo and suggest that expansion of the APOBEC3 locus in primates may have helped to provide for the continued restraint of ERV in the human genome.IMPORTANCE Although APOBEC3 proteins are known to be important antiviral restriction factors in both mice and humans, their roles in the restriction of endogenous retroviruses (ERV) have been limited to in vitro studies. Here, we report that human APOBEC3G expressed as a transgene in mice prevents the emergence of infectious ERV from endogenous loci. This study reveals that APOBEC3G can powerfully restrict active retrotransposons in vivo and demonstrates how transgenic mice can be used to investigate host mechanisms that inhibit retrotransposons and reinforce genomic integrity.

Mx1 reveals innate pathways to antiviral resistance and lethal influenza disease.

Influenza A virus (IAV) causes up to half a million deaths worldwide annually, 90% of which occur in older adults. We show that IAV-infected monocytes from older humans have impaired antiviral interferon production but retain intact inflammasome responses. To understand the in vivo consequence, we used mice expressing a functional Mx gene encoding a major interferon-induced effector against IAV in humans. In Mx1-intact mice with weakened resistance due to deficiencies in Mavs and Tlr7, we found an elevated respiratory bacterial burden. Notably, mortality in the absence of Mavs and Tlr7 was independent of viral load or MyD88-dependent signaling but dependent on bacterial burden, caspase-1/11, and neutrophil-dependent tissue damage. Therefore, in the context of weakened antiviral resistance, vulnerability to IAV disease is a function of caspase-dependent pathology.

Interactions between ß-catenin and the HSlo potassium channel regulates HSlo surface expression.

BACKGROUND: The large conductance calcium-activated potassium channel alpha-subunit (Slo) is widely distributed throughout the body and plays an important role in a number of diseases. Prior work has shown that Slo, through its S10 region, interacts with ß-catenin, a key component of the cytoskeleton framework and the Wnt signaling pathway. However, the physiological significance of this interaction was not clear. METHODOLOGY/PRINCIPAL FINDINGS: Using a combination of proteomic and cell biology tools we show the existence of additional multiple binding sites in Slo, and explore in detail ß-catenin interactions with the S10 region. We demonstrate that deletion of this region reduces Slo surface expression in HEK cells, which indicates that interaction with beta-catenin is important for Slo surface expression. This is confirmed by reduced expression of Slo in HEK cells and chicken (Gallus gallus domesticus leghorn white) hair cells treated with siRNA to ß-catenin. HSlo reciprocally co-immunoprecipitates with ß-catenin, indicating a stable binding between these two proteins, with the S10 deletion mutant having reduced binding with ß-catenin. We also observed that mutations of the two putative GSK phosphorylation sites within the S10 region affect both the surface expression of Slo and the channel's voltage and calcium sensitivities. Interestingly, expression of exogenous Slo in HEK cells inhibits ß-catenin-dependent canonical Wnt signaling. CONCLUSIONS AND SIGNIFICANCE: These studies identify for the first time a central role for ß-catenin in mediating Slo surface expression. Additionally we show that Slo overexpression can lead to downregulation of Wnt signaling.

Differential impairment of spatial and nonspatial cognition in a mouse model of brain aging.

AIMS: Chronic exposure to d-galactose (D-Gal), which causes acceleration in aging and simulated symptoms of natural senescence, has been used as a reliable animal model of aging. However, the different influences of D-Gal on spatial and nonspatial cognition are as yet unclear. MAIN METHODS: In the present study, the object recognition test (ORT), object location test (OLT) and Y-maze test were carried out to assess the cognitive performance of mice after 8 weeks of chronic D-Gal exposure. The expression of oxidative-stress biomarkers in the prefrontal cortex (PFC) and caspase-3 in the hippocampus (HIP) were also determined. KEY FINDINGS: The results of the behavioral tests indicated that after chronic D-Gal exposure, the spatial memory of mice was seriously impaired, whereas nonspatial cognition remained intact. D-Gal exposure also induced more significant changes in malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities in the HIP than in the PFC. Furthermore, chronic D-Gal exposure triggered more substantial caspase-3 overexpression in the HIP than in the PFC. SIGNIFICANCE: Together, these findings suggest the impairment of spatial, but not nonspatial, cognitive ability after chronic D-Gal exposure. The differential nature of this impairment might be due to the more substantial reduction of antioxidant enzyme activities and more severe neuronal apoptosis mediated by caspase-3 in the HIP. The present results also indicate that the HIP and HIP-dependent spatial cognition might be more susceptible to oxidative stress during senescence or other pathological processes.

Degradation of the bile salt export pump at endoplasmic reticulum in progressive familial intrahepatic cholestasis type II.

The bile salt export pump (Bsep) represents the major bile salt transport system at the canalicular membrane of hepatocytes. When examined in model cell lines, genetic mutations in the BSEP gene impair its targeting and transport function, contributing to the pathogenesis of progressive familial intrahepatic cholestasis type II (PFIC II). PFIC II mutations are known to lead to a deficiency of BSEP in human hepatocytes, suggesting that PFIC II mutants are unstable and degraded in the cell. To investigate this further, we have characterized the impact of several PFIC II mutations on the processing and stability of rat Bsep. G238V, D482G, G982R, R1153C, and R1286Q all retain Bsep to the endoplasmic reticulum (ER) to different extents. Except for R1153C, the PFIC II mutants are degraded with varying half-lives. G238V and D482G are partially misfolded and can be stabilized by low temperature and glycerol. The proteasome provides the major degradation pathway for the PFIC II mutants, whereas the lysosome also contributes to the degradation of D482G. The PFIC II mutants appear to be more heavily ubiquitinated compared with the wild-type (wt) Bsep, and their ubiquitination is increased by the proteasome inhibitors. Overexpression of several E3 ubiquitin ligases, which are involved in ER-associated degradation (ERAD), lead to the decrease of both mutant and wt Bsep. Gene knockdown studies showed that the ERAD E3s Rma1 and TEB4 contribute to the degradation of G238V, whereas HRD1 contributes to the degradation of a mutant lacking the lumenal glycosylation domain (DeltaGly). Furthermore, we present evidence that G982R weakly associates with various components of the ER quality control system. These data together demonstrate that the PFIC II mutants except R1153C and DeltaGly are degraded by the ERAD pathway.