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Leukocyte infiltration and trafficking during in-flammatory states in the newborn mouse brain

Hellman, Lisa (2014) MOBM29 20141
Degree Projects in Molecular Biology
Abstract
Objective: Inflammation is associated with higher incidence of perinatal brain injury. To better understand the mechanisms behind these injuries, we have studied the immune cell trafficking into the central nervous system (CNS) through the choroid plexus (CP) in the newborn. Meth-ods: Inflammation was induced in newborn mice using two different toll-like receptor ago-nists: PAM3CSK4 (PAM) and lipopolysaccharide (LPS). The number of leukocytes in the cer-ebrospinal fluid (CSF) was estimated at 6, 14, 24 and 48 hours after agonist injection. The location and number of white blood cells present in the brain and CP at 14 hours after agonist treatment was determined by immunofluorescence. Finally, the tight junction proteins in the CP were... (More)
Objective: Inflammation is associated with higher incidence of perinatal brain injury. To better understand the mechanisms behind these injuries, we have studied the immune cell trafficking into the central nervous system (CNS) through the choroid plexus (CP) in the newborn. Meth-ods: Inflammation was induced in newborn mice using two different toll-like receptor ago-nists: PAM3CSK4 (PAM) and lipopolysaccharide (LPS). The number of leukocytes in the cer-ebrospinal fluid (CSF) was estimated at 6, 14, 24 and 48 hours after agonist injection. The location and number of white blood cells present in the brain and CP at 14 hours after agonist treatment was determined by immunofluorescence. Finally, the tight junction proteins in the CP were studied by immunofluorescence. Results: The number of leukocytes in the CSF of PAM treated animals peaked at 14 h, and was significantly higher than in the LPS and control animals. In addition, the number of leukocytes in the CP and the brain was significantly high-er in PAM injected animals than in the control and LPS groups. In the PAM treated animals, large clusters of cells were frequently seen in the meningeal border but also in blood vessels and some in the brain parenchyma. There were no visible changes in the staining pattern of the tight junction proteins in the CP. Interpretation: After peripheral stimulation of TLR-1/2, leu-kocytes may be migrating through the CP, but they may also be moving through the other bar-riers of the CNS. (Less)
Popular Abstract
Immune cells caught in motion entering the newborn brain

Infection and inflammation in the brain of the newborn can cause lifelong injuries, and may play a role in neurological disorders such as autism, schizophrenia and cerebral palsy. In some cases, researchers have found that an infection outside the newborn brain also may be important for the development of these disorders.

The aim of this project was to try to better understand how an inflammation that started somewhere else in the body can move into the newborn brain. In the brain there is a small organ called the choroid plexus that produces the fluid surrounding the brain and spinal cord (cerebrospinal fluid). But this is not the only task this organ is involved in, it also... (More)
Immune cells caught in motion entering the newborn brain

Infection and inflammation in the brain of the newborn can cause lifelong injuries, and may play a role in neurological disorders such as autism, schizophrenia and cerebral palsy. In some cases, researchers have found that an infection outside the newborn brain also may be important for the development of these disorders.

The aim of this project was to try to better understand how an inflammation that started somewhere else in the body can move into the newborn brain. In the brain there is a small organ called the choroid plexus that produces the fluid surrounding the brain and spinal cord (cerebrospinal fluid). But this is not the only task this organ is involved in, it also has a part in the brain’s response to infection and/or inflammation. When there is an infection in the body, immune cells can make their way into the brain and spinal cord (central nervous system, CNS) through the choroid plexus; it acts as a selective barrier whereby immune cells can enter the CNS while keeping other cells out.

The number of immune cells in the cerebrospinal fluid was counted at different time points after inflammation to quantify cell infiltration. To be able to study the movement of immune cells, an antibody directed against immune cells was used to visualize and count the immune cells in the brain of newborn mice. At 14 hours before the counting of immune cells, inflam-matory agents were injected into mice pups. Furthermore, proteins making up the barrier in the choroid plexus were visualized with green/red fluorescent antibodies.

Immune cells may move across the choroid plexus
After injection of inflammatory agent there was an in-crease in immune cells in the choroid plexus and the whole brain. Accompanied by this was a dramatic in-crease of immune cells in the cerebrospinal fluid. The staining of the barrier proteins in the choroid plexus showed no change in appearance after inflammation.

The result show that inflammation in the body can result in great infiltration of immune cells into the brain. They indicate movement of cells across the choroid plexus with no apparent change of the properties of the barrier, al-though infiltration may also occur at other sites of the brain. These results are important to better understand the immune cell trafficking into the brain of newborns, since it may play a role in the development of a variety of neu-rological disorders.

Advisor: Joakim Ek, Amin Mottahedin
Master´s Degree Project 30 credits in Molecular Biology with specialization in Medical Biology* 2014
Inst. for Neuroscience and Physiology, University of Gothenburg
*Subject of Master´s Degree Project: Neurobiology (Less)
Please use this url to cite or link to this publication:
author
Hellman, Lisa
supervisor
organization
course
MOBM29 20141
year
type
L3 - Miscellaneous, Projetcs etc.
subject
language
English
id
4699023
date added to LUP
2014-10-20 14:23:35
date last changed
2014-10-20 14:23:35
@misc{4699023,
  abstract     = {Objective: Inflammation is associated with higher incidence of perinatal brain injury. To better understand the mechanisms behind these injuries, we have studied the immune cell trafficking into the central nervous system (CNS) through the choroid plexus (CP) in the newborn. Meth-ods: Inflammation was induced in newborn mice using two different toll-like receptor ago-nists: PAM3CSK4 (PAM) and lipopolysaccharide (LPS). The number of leukocytes in the cer-ebrospinal fluid (CSF) was estimated at 6, 14, 24 and 48 hours after agonist injection. The location and number of white blood cells present in the brain and CP at 14 hours after agonist treatment was determined by immunofluorescence. Finally, the tight junction proteins in the CP were studied by immunofluorescence. Results: The number of leukocytes in the CSF of PAM treated animals peaked at 14 h, and was significantly higher than in the LPS and control animals. In addition, the number of leukocytes in the CP and the brain was significantly high-er in PAM injected animals than in the control and LPS groups. In the PAM treated animals, large clusters of cells were frequently seen in the meningeal border but also in blood vessels and some in the brain parenchyma. There were no visible changes in the staining pattern of the tight junction proteins in the CP. Interpretation: After peripheral stimulation of TLR-1/2, leu-kocytes may be migrating through the CP, but they may also be moving through the other bar-riers of the CNS.},
  author       = {Hellman, Lisa},
  language     = {eng},
  note         = {Student Paper},
  title        = {Leukocyte infiltration and trafficking during in-flammatory states in the newborn mouse brain},
  year         = {2014},
}