Limits...
A human lung xenograft mouse model of Nipah virus infection.

Valbuena G, Halliday H, Borisevich V, Goez Y, Rockx B - PLoS Pathog. (2014)

Bottom Line: NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation.NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi.In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America; Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
Nipah virus (NiV) is a member of the genus Henipavirus (family Paramyxoviridae) that causes severe and often lethal respiratory illness and encephalitis in humans with high mortality rates (up to 92%). NiV can cause Acute Lung Injury (ALI) in humans, and human-to-human transmission has been observed in recent outbreaks of NiV. While the exact route of transmission to humans is not known, we have previously shown that NiV can efficiently infect human respiratory epithelial cells. The molecular mechanisms of NiV-associated ALI in the human respiratory tract are unknown. Thus, there is an urgent need for models of henipavirus infection of the human respiratory tract to study the pathogenesis and understand the host responses. Here, we describe a novel human lung xenograft model in mice to study the pathogenesis of NiV. Following transplantation, human fetal lung xenografts rapidly graft and develop mature structures of adult lungs including cartilage, vascular vessels, ciliated pseudostratified columnar epithelium, and primitive "air" spaces filled with mucus and lined by cuboidal to flat epithelium. Following infection, NiV grows to high titers (10(7) TCID50/gram lung tissue) as early as 3 days post infection (pi). NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation. NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi. In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI. This model will facilitate progress in the fundamental understanding of henipavirus pathogenesis and virus-host interactions; it will also provide biologically relevant models for other respiratory viruses.

Show MeSH

Related in: MedlinePlus

Nipah virus replication in human lung xenografts.Virus replication was determined in human lung (A) and mouse (B) tissues at days 1, 3, 5, 7 and 10 post infection by virus titration. Titers were determined in human lung following primary (direct injection) or secondary (infection due to viremia). Samples from three animals were assayed and analyzed and the mean titers were calculated as TCID50/gram tissue. The error bars represent the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3974875&req=5

ppat-1004063-g002: Nipah virus replication in human lung xenografts.Virus replication was determined in human lung (A) and mouse (B) tissues at days 1, 3, 5, 7 and 10 post infection by virus titration. Titers were determined in human lung following primary (direct injection) or secondary (infection due to viremia). Samples from three animals were assayed and analyzed and the mean titers were calculated as TCID50/gram tissue. The error bars represent the standard deviation.

Mentions: Natural NiV infection involves exposure to the virus through the respiratory epithelium. To mimic this route in human lung xenografts that lack air exchange, tissues were directly injected with NiV. Following direct intragraft injection of the 3 lung tissues on the left side (primary infection) within each mouse, NSG mice did not show any signs of morbidity or mortality during our observation period of 10 days. In addition, two non-grafted NSG mice that were challenged intradermally as controls, with the same dose as xenografts, did not develop any clinical signs. Primary infection of the human lung xenografts resulted in detection of infectious NiV as early as 1 day post infection (Figure 2A) and NiV replicated to high titers (107 TCID50/gram tissue) by day 3 post infection. NiV titers remained high until the end of the experiment at 10 days post infection. Importantly, high titers of NiV were also detected in the other 3 lung tissues (on the right side of each mouse) that were not initially infected through direct intragraft injection as early as 3 days post infection. This finding clearly demonstrates that the virus can spread from infected human lung grafts to uninfected grafts in the same mouse, most likely through viremia (secondary infection; Figure 2A). The presence of viremia was further supported by the observation that infectious NiV was detected, albeit at lower levels, in several mouse tissues including lung, brain, heart, spleen and kidney at various time points post infection (Figure 2B). In fact, viremia was detected in a blood sample of 1 animal on day 10 post infection in which a low level (300 TCID50/mL) of infectious NiV was determined (Table 1). Interestingly, virus was not detected in organs from non-grafted NSG mice that were challenged intradermally with the same dose (Table 1), suggesting the NSG mouse tissues are probably not intrinsically susceptible to NiV. In order to confirm that the human lung xenografts could be infected via the hematogenous route, we next challenged 2 lung-engrafted NSG mice with NiV via the IP route. The IP challenge with NiV in this model confirmed that infection resulted in detectable viremia in 1 animal with virus spreading to the human lung xenografts in both, replicating to high titers and resulting in histopathological changes similar to those observed with intragraft challenge (Table 1). Together, these data suggest that following intragraft infection, the human lung is highly susceptible to NiV infection and results in viremia and subsequent spread to other organs in the absence of disease.


A human lung xenograft mouse model of Nipah virus infection.

Valbuena G, Halliday H, Borisevich V, Goez Y, Rockx B - PLoS Pathog. (2014)

Nipah virus replication in human lung xenografts.Virus replication was determined in human lung (A) and mouse (B) tissues at days 1, 3, 5, 7 and 10 post infection by virus titration. Titers were determined in human lung following primary (direct injection) or secondary (infection due to viremia). Samples from three animals were assayed and analyzed and the mean titers were calculated as TCID50/gram tissue. The error bars represent the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3974875&req=5

ppat-1004063-g002: Nipah virus replication in human lung xenografts.Virus replication was determined in human lung (A) and mouse (B) tissues at days 1, 3, 5, 7 and 10 post infection by virus titration. Titers were determined in human lung following primary (direct injection) or secondary (infection due to viremia). Samples from three animals were assayed and analyzed and the mean titers were calculated as TCID50/gram tissue. The error bars represent the standard deviation.
Mentions: Natural NiV infection involves exposure to the virus through the respiratory epithelium. To mimic this route in human lung xenografts that lack air exchange, tissues were directly injected with NiV. Following direct intragraft injection of the 3 lung tissues on the left side (primary infection) within each mouse, NSG mice did not show any signs of morbidity or mortality during our observation period of 10 days. In addition, two non-grafted NSG mice that were challenged intradermally as controls, with the same dose as xenografts, did not develop any clinical signs. Primary infection of the human lung xenografts resulted in detection of infectious NiV as early as 1 day post infection (Figure 2A) and NiV replicated to high titers (107 TCID50/gram tissue) by day 3 post infection. NiV titers remained high until the end of the experiment at 10 days post infection. Importantly, high titers of NiV were also detected in the other 3 lung tissues (on the right side of each mouse) that were not initially infected through direct intragraft injection as early as 3 days post infection. This finding clearly demonstrates that the virus can spread from infected human lung grafts to uninfected grafts in the same mouse, most likely through viremia (secondary infection; Figure 2A). The presence of viremia was further supported by the observation that infectious NiV was detected, albeit at lower levels, in several mouse tissues including lung, brain, heart, spleen and kidney at various time points post infection (Figure 2B). In fact, viremia was detected in a blood sample of 1 animal on day 10 post infection in which a low level (300 TCID50/mL) of infectious NiV was determined (Table 1). Interestingly, virus was not detected in organs from non-grafted NSG mice that were challenged intradermally with the same dose (Table 1), suggesting the NSG mouse tissues are probably not intrinsically susceptible to NiV. In order to confirm that the human lung xenografts could be infected via the hematogenous route, we next challenged 2 lung-engrafted NSG mice with NiV via the IP route. The IP challenge with NiV in this model confirmed that infection resulted in detectable viremia in 1 animal with virus spreading to the human lung xenografts in both, replicating to high titers and resulting in histopathological changes similar to those observed with intragraft challenge (Table 1). Together, these data suggest that following intragraft infection, the human lung is highly susceptible to NiV infection and results in viremia and subsequent spread to other organs in the absence of disease.

Bottom Line: NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation.NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi.In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America; Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
Nipah virus (NiV) is a member of the genus Henipavirus (family Paramyxoviridae) that causes severe and often lethal respiratory illness and encephalitis in humans with high mortality rates (up to 92%). NiV can cause Acute Lung Injury (ALI) in humans, and human-to-human transmission has been observed in recent outbreaks of NiV. While the exact route of transmission to humans is not known, we have previously shown that NiV can efficiently infect human respiratory epithelial cells. The molecular mechanisms of NiV-associated ALI in the human respiratory tract are unknown. Thus, there is an urgent need for models of henipavirus infection of the human respiratory tract to study the pathogenesis and understand the host responses. Here, we describe a novel human lung xenograft model in mice to study the pathogenesis of NiV. Following transplantation, human fetal lung xenografts rapidly graft and develop mature structures of adult lungs including cartilage, vascular vessels, ciliated pseudostratified columnar epithelium, and primitive "air" spaces filled with mucus and lined by cuboidal to flat epithelium. Following infection, NiV grows to high titers (10(7) TCID50/gram lung tissue) as early as 3 days post infection (pi). NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation. NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi. In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI. This model will facilitate progress in the fundamental understanding of henipavirus pathogenesis and virus-host interactions; it will also provide biologically relevant models for other respiratory viruses.

Show MeSH
Related in: MedlinePlus