- Email: [email protected]
In vivo evaluation of the therapeutic potential of novel translocator protein (TSPO) ligands for the treatment of Alzheimer’s disease
P156
Podium Presentations: Sunday, July 19, 2015
time of occurrence of these events make this a feasible composite endpoint for clinical trials in predementia AD, using TTE or responder analysis approaches. O1-10-06
INTERNET-BASED RECRUITMENT OF SUBJECTS FOR PRODROMAL AND SECONDARY PREVENTION ALZHEIMER’S DISEASE TRIALS USING THE BRAIN HEALTH REGISTRY
Rachel L. Nosheny1, Derek Flennkiken2, Philip S. Insel2, Shannon Finley2, Scott Mackin3, Monica Camacho2, Diana Truran-Sacrey4, Paul Maruff5, Michael W. Weiner6, 1San Francisco Veteran’s Administration Medical Center, San Francisco, CA, USA; 2San Francisco Veteran’s Administration Medical Center, San Francisco, CA, USA; 3UCSF, San Francisco, CA, USA; 4 Center for Imaging of Neurodegenerative Diseases, San Francisco, CA, USA; 5 Cogstate Ltd., Melbourne, Australia; 6University of California San Francisco, San Francisco, CA, USA. Contact e-mail: [email protected] Background: The high cost of recruiting and screening Alzheimer’s
disease (AD) clinical trial subjects is a major obstacle to developing effective treatments. Many AD clinical trials target cognitivelynormal subjects at risk for AD. BrainHealthRegistry.org (BHR) is an internet-based registry designed to reduce costs and accelerate completion of clinical trials for AD by facilitating recruitment and screening. Methods: After registration and consent, BHR subjects complete health and lifestyle questionnaires and neuropsychological tests (NPTs), including the Cogstate Brief Battery, online with no supervision. We analyzed the eligibility of BHR subjects, both nationally and within the San Francisco Bay Area (SFBA), for prodromal and secondary prevention AD clinical trials based on age, NPT scores, and other common inclusion/exclusion criteria. We used linear regression to compare subjects recruited using various outreach and advertising strategies. Results: The BHR has over 11,000 subjects, with 46% residing in the SFBA. The average age is 57614.6 years; 6704 registrants are over 55. Three percent of older adults report having dementia, 76% report a family history of AD, and 45% endorse a memory problem. Fifty-seven percent of registrants (3759 subjects) over age 55 pass a mock screening process excluding subjects with neurological disease, recent drug/ alcohol abuse, and use of AD medications. In the general older adult BHR cohort, 1579 subjects have low NPT scores (at least 1 SD below the mean). Of these, 87% (1379 subjects) also endorse a memory complaint. In the SFBA, 718 older adults have low NPT scores, 82% of those (587 subjects) endorse a memory complaint, 332 subjects passed the mock screening process, and 44% report family history AD. There was a significant association between recruitment strategy and subject age (p<0.01), subjective memory problems, and family history of AD (p<0.001). Conclusions: The BHR cohort contains a significant number of subjects who would be eligible for prodromal and secondary prevention AD trials, including subjects residing in the SFBA, demonstrating the feasibility of assembling a cohort for clinical trials using an
Internet-based registry. Quantitative analysis of the effectiveness of recruitment strategies is crucial for targeting usable subjects in order to facilitate the development of new AD treatments. SUNDAY, JULY 19, 2015 ORAL SESSIONS O1-11 PRECLINICAL: PRECLINICAL INFLAMMATION AND OTHER O1-11-01
TARGETING CALCIUM CHANNELS AS A NOVEL THERAPEUTIC STRATEGY FOR ALZHEIMER’S DISEASE: PREVENTING PATHOLOGY FROM MOLECULAR TO NETWORK LEVELS
Grace E. Stutzmann, RFUMS, North Chicago, IL, USA. Contact e-mail: [email protected] Background: An early pathogenic mechanism that affects all the major features and cognitive deficits associated with AD is dysregulated intracellular calcium signaling. In particular, ryanodine-receptor (RyR) mediated calcium is markedly increased in spines and synaptic compartments, and likely plays a proximal role in synaptic pathophysiology. Conversely, preventing the exaggerated calcium responses generated from intracellular stores may be a novel and effective therapeutic strategy for AD. Methods: Using a combination of approaches in AD mouse models (3xTg-AD, APP/PS1, and TgCRND8), including 2-photon calcium imaging and whole cell patch clamp recordings in hippocampal neurons, EM and confocal microscopy, and synaptic physiology to measure plasticity in local circuits and hippocampal networks, we tested the effects of existing and novel RyR modulators that will stabilize intracellular calcium signaling in neurons from AD mice. Results: In presymptomatic and symptomatic AD mice, sub-chronic treatment with RyR-targeted compounds prevented a broad range of AD-related symptoms, including aberrant calcium signaling, synaptic transmission and plasticity deficits, structural impairments at the synaptic and ultrastructural levels, amyloid and tau histopathology, and molecular alterations in RyR expression levels. Conclusions: Stabilizing the RyR-evoked calcium responses in AD mouse models was effective in preventing a broad range of neuropathological features associated with AD. The breadth of targets affected by this approach likely reflects the upstream and central role that dysregulated calcium plays in the overall disease process. Thus, a RyR-targeted strategy may provide the needed combinatorial algorithm to prevent the multifaceted pathological progression of AD.
O1-11-02
IN VIVO EVALUATION OF THE THERAPEUTIC POTENTIAL OF NOVEL TRANSLOCATOR PROTEIN (TSPO) LIGANDS FOR THE TREATMENT OF ALZHEIMER’S DISEASE
Prita Riana Asih1,2, Bin Ji3, Andrew Katsifis4, Filomena Mattner4, Donatella Caruso5, Roberto Cosimo Melcangi5, Makoto Higuchi3, Ralph N. Martins6,7, Anna M. Barron3, 1University of New South Wales, Sydney, Australia; 2Sir James McCusker Alzheimer’s Disease Research Unit, Perth, Australia; 3National Institute of Radiological Science, Tokyo, Japan; 4Royal Prince Alfred Hospital, Sydney, Australia; 5The University of Milan, Milan, Italy; 6Sir James McCusker Alzheimer’s Disease Research Unit (Hollywood Private Hospital), Perth, Australia; 7Edith Cowan University, Perth, Australia. Contact e-mail: [email protected] Background: Ligands
of the translocator protein (TSPO) have been identified as promising candidate therapeutic agents for several neurodegenerative disorders due to their ability to enhance neurosteroidogenesis. We have previously
Podium Presentations: Sunday, July 19, 2015
demonstrated that the classic TSPO ligands, Ro5-4864 and PK11195, increase brain steroid levels, reduce Ab accumulation, and improve cognition in a mouse model of AD. Here we evaluated the steroidogenic efficacy and acute behavioral effects of three TSPO imidazopyridine ligands, CLINDE, PBR175, and PBR162, which we have previously shown to be non-toxic in vitro. CLINDE, which exhibited the most favorable behavioral and pharmacokinetic profile, was investigated further for its specificity and binding affinity in human brain. Methods: The acute behavioural effects of the three novel TSPO ligands were compared with Ro5-4864, in 3 month old castrated C57BL/6J mice. Two hours after ligand injection (3 mg/kg i.p.), anxiety-, depression-, and memory-related behaviors were assessed in the elevated-plus maze, open field maze, tail-suspension test, and object recognition tests respectively. Brain steroids levels were measured by LC-MS/MS. To determine if the behavioral effects of TSPO ligands were mediated via increased neurosteroidogenesis, mice were pretreated with a steroidogenesis inhibitor, aminogluthetimide (10mg/ kg). The pharmacokinetic properties of the novel ligands were assessed by competitive PET imaging [11C]PK-11195. The specificity of action of CLINDE was determined in TSPO knockout mice, and the affinity for TSPO (Ki value) in human brain homogenate was investigated in vitro by [11C] PK-11195 binding assay. Results: CLINDE and PBR175 improved learning and memory performance equally well as Ro5-4864. These improvements were completely ablated by aminogluthetimide, confirming that the beneficial effects were mediated through an increase in neurosteroidogenesis. Anxietyand depression-related behaviors were unaffected by the TSPO ligands. Competitive PET studies indicated that CLINDE showed the most long lasting binding to TSPO. The specificity of behavioral effects of CLINDE was confirmed. The affinity of CLINDE in high-affinity binder (HAB) and low-affinity binder (LAB) subjects were 5.5 and 29.7 respectively. Conclusions: These findings indicate that CLINDE and PBR175 rapidly promote neurosteroidogenesis, thereby enhancing learning and memory in vivo. These second generation TSPO ligands are promising therapeutic candidates with improved pharmacokinetic properties compared to classic TSPO ligands.
O1-11-03
MODULATING CHEMOKINE SIGNALING IN PRECLINICAL ALZHEIMER’S DISEASE MODELS
Todd Golde1, Yona Levites1, Pedro E. Cruz1, Awilda M. Rosario1, Paramita Chakrabarty1, Corey Moran1, Xuefei Liu1, Carolina CeballosDiaz1, Brenda Moore1, Nathan D. Price2, Corey Funk2, 1University of Florida, Gainesville, FL, USA; 2The Institute for Systems Biology, Seattle, WA, USA. Contact e-mail: [email protected] Background: Most disease modifying therapies in AD target the
protein aggregation process that is thought to trigger the disease or involve some form of neuroprotective strategy. It has been shown that changes in transcriptional networks of innate immunity genes are likely to play a key role in AD. We have been using custom Nanostring array to assess changes in innate immune gene expression in the brains of APP and Tau transgenic mouse models. As expected, these experiments demonstrated extensive innate immune activation in transgenic mice. Thus, we hypothesize that select innate immune signaling factors elevated in AD and in AD mouse models, will have an effect on cognition and amyloid deposition when overexpressed in the brain following
P157
AAV delivery. Methods: We cloned an array of chemokines as well as truncated chemokines that are known for their dominant negative effects into pAAV. Then we expressed these chemokines in the brains of newborn transgenic CRND8 mice, using of somatic brain transgenic approach. Effects on cognition and amyloid pathology are assessed at three and six month of age. In the first part of the study the chemokines are assessed for their effects on behavior in non-transgenic mice, by fear conditioning testing. The second part focuses on chemokines effects on amyloid pathology in CRDN8 mice. Amyloid levels are assessed by biochemical and immunohistochemical methods. Results: First we have assessed for effects of chemokines overexpression on behavior in non-transgenic mice. CXCL10 overexpression resulted in a trend toward memory impairment in three month old non-transgenic CRND8 mice as assessed by fear conditioning testing. In contrast, amyloid pathology in 6 month old CRND8 mice overexpressing CXCL10, was reduced as compared to control, PBS injected mice. Currently we are assessing effects of overexpression and downregulation of additional chemokines on behavior and amyloid pathology in CRND8 mouse model. Additionally, RNAsec analysis from mouse and human studies is underway. Conclusions: These studies provide an insight on effects of manipulation of the innate immunity on amyloid pathology formation and deposition in CRND8 mice.
O1-11-04
TARGETING LEUKOCYTE INTEGRINS HAS THERAPEUTIC EFFECT IN ALZHEIMER’S-LIKE DISEASE
Gabriela Constantin, Enrica Caterina Pietronigro, Elena Zenaro, Gennj Piacentino, Vittorina Della Bianca, Maria Giovanna Rossi, Carlo Laudanna, University of Verona, Verona, Italy. Contact e-mail: [email protected] Background: Vascular inflammation and a dysfunctional bloodbrain-barrier have been implicated in the pathogenesis of Alzheimer’s disease. However, the role of leukocyte trafficking mechanisms in Alzheimer’s disease in the induction of neuropathological changes and memory deficit is unclear. Methods: We carried out two-photon laser-scanning microscopy (TPLSM) experiments in the brain of mice with five familial Alzheimer’s disease (5xFAD) mutations presenting amyloid pathology, and 3xTgAD mice with both amyloid and tau pathology and observed that fluorescently labeled neutrophils and activated lymphocytes adhere to the vascular endothelium and migrate into the brain parenchyma in these animals. Results: Blocking monoclonal antibodies to LFA-1 (alphaLbeta2) and VLA-4 (alpha4beta1) integrins significantly inhibited neutrophil and lymphocyte adhesion in brain vessels, suggesting that leukocyte integrins play a role in leukocyte extravasation in Alzheimer’s disease models. In addition, our TPLSM data showed that leukocytes from LFA1 deficient mice are completely unable to adhere or crawl in the blood vessels and thus to transmigrate in the brain parenchyma of Alzheimer’s disease mice. LFA1 or VLA-4 inhibition using monoclonal antibodies clearly improved memory function compared to mice treated with a control antibody, restoring performance to levels comparable with wild-type age-matched littermates in Y maze and contextual fear conditioning tests. The role of LFA-1 integrin was confirmed by crossing 3xTg-AD animals with the LFA-1-deficient Itgal-/- strain. We found that the 3xTgAD mice lacking LFA-1 integrin showed improved memory in cognitive tests compared to wild-type animals. These findings
Podium Presentations: Sunday, July 19, 2015
time of occurrence of these events make this a feasible composite endpoint for clinical trials in predementia AD, using TTE or responder analysis approaches. O1-10-06
INTERNET-BASED RECRUITMENT OF SUBJECTS FOR PRODROMAL AND SECONDARY PREVENTION ALZHEIMER’S DISEASE TRIALS USING THE BRAIN HEALTH REGISTRY
Rachel L. Nosheny1, Derek Flennkiken2, Philip S. Insel2, Shannon Finley2, Scott Mackin3, Monica Camacho2, Diana Truran-Sacrey4, Paul Maruff5, Michael W. Weiner6, 1San Francisco Veteran’s Administration Medical Center, San Francisco, CA, USA; 2San Francisco Veteran’s Administration Medical Center, San Francisco, CA, USA; 3UCSF, San Francisco, CA, USA; 4 Center for Imaging of Neurodegenerative Diseases, San Francisco, CA, USA; 5 Cogstate Ltd., Melbourne, Australia; 6University of California San Francisco, San Francisco, CA, USA. Contact e-mail: [email protected] Background: The high cost of recruiting and screening Alzheimer’s
disease (AD) clinical trial subjects is a major obstacle to developing effective treatments. Many AD clinical trials target cognitivelynormal subjects at risk for AD. BrainHealthRegistry.org (BHR) is an internet-based registry designed to reduce costs and accelerate completion of clinical trials for AD by facilitating recruitment and screening. Methods: After registration and consent, BHR subjects complete health and lifestyle questionnaires and neuropsychological tests (NPTs), including the Cogstate Brief Battery, online with no supervision. We analyzed the eligibility of BHR subjects, both nationally and within the San Francisco Bay Area (SFBA), for prodromal and secondary prevention AD clinical trials based on age, NPT scores, and other common inclusion/exclusion criteria. We used linear regression to compare subjects recruited using various outreach and advertising strategies. Results: The BHR has over 11,000 subjects, with 46% residing in the SFBA. The average age is 57614.6 years; 6704 registrants are over 55. Three percent of older adults report having dementia, 76% report a family history of AD, and 45% endorse a memory problem. Fifty-seven percent of registrants (3759 subjects) over age 55 pass a mock screening process excluding subjects with neurological disease, recent drug/ alcohol abuse, and use of AD medications. In the general older adult BHR cohort, 1579 subjects have low NPT scores (at least 1 SD below the mean). Of these, 87% (1379 subjects) also endorse a memory complaint. In the SFBA, 718 older adults have low NPT scores, 82% of those (587 subjects) endorse a memory complaint, 332 subjects passed the mock screening process, and 44% report family history AD. There was a significant association between recruitment strategy and subject age (p<0.01), subjective memory problems, and family history of AD (p<0.001). Conclusions: The BHR cohort contains a significant number of subjects who would be eligible for prodromal and secondary prevention AD trials, including subjects residing in the SFBA, demonstrating the feasibility of assembling a cohort for clinical trials using an
Internet-based registry. Quantitative analysis of the effectiveness of recruitment strategies is crucial for targeting usable subjects in order to facilitate the development of new AD treatments. SUNDAY, JULY 19, 2015 ORAL SESSIONS O1-11 PRECLINICAL: PRECLINICAL INFLAMMATION AND OTHER O1-11-01
TARGETING CALCIUM CHANNELS AS A NOVEL THERAPEUTIC STRATEGY FOR ALZHEIMER’S DISEASE: PREVENTING PATHOLOGY FROM MOLECULAR TO NETWORK LEVELS
Grace E. Stutzmann, RFUMS, North Chicago, IL, USA. Contact e-mail: [email protected] Background: An early pathogenic mechanism that affects all the major features and cognitive deficits associated with AD is dysregulated intracellular calcium signaling. In particular, ryanodine-receptor (RyR) mediated calcium is markedly increased in spines and synaptic compartments, and likely plays a proximal role in synaptic pathophysiology. Conversely, preventing the exaggerated calcium responses generated from intracellular stores may be a novel and effective therapeutic strategy for AD. Methods: Using a combination of approaches in AD mouse models (3xTg-AD, APP/PS1, and TgCRND8), including 2-photon calcium imaging and whole cell patch clamp recordings in hippocampal neurons, EM and confocal microscopy, and synaptic physiology to measure plasticity in local circuits and hippocampal networks, we tested the effects of existing and novel RyR modulators that will stabilize intracellular calcium signaling in neurons from AD mice. Results: In presymptomatic and symptomatic AD mice, sub-chronic treatment with RyR-targeted compounds prevented a broad range of AD-related symptoms, including aberrant calcium signaling, synaptic transmission and plasticity deficits, structural impairments at the synaptic and ultrastructural levels, amyloid and tau histopathology, and molecular alterations in RyR expression levels. Conclusions: Stabilizing the RyR-evoked calcium responses in AD mouse models was effective in preventing a broad range of neuropathological features associated with AD. The breadth of targets affected by this approach likely reflects the upstream and central role that dysregulated calcium plays in the overall disease process. Thus, a RyR-targeted strategy may provide the needed combinatorial algorithm to prevent the multifaceted pathological progression of AD.
O1-11-02
IN VIVO EVALUATION OF THE THERAPEUTIC POTENTIAL OF NOVEL TRANSLOCATOR PROTEIN (TSPO) LIGANDS FOR THE TREATMENT OF ALZHEIMER’S DISEASE
Prita Riana Asih1,2, Bin Ji3, Andrew Katsifis4, Filomena Mattner4, Donatella Caruso5, Roberto Cosimo Melcangi5, Makoto Higuchi3, Ralph N. Martins6,7, Anna M. Barron3, 1University of New South Wales, Sydney, Australia; 2Sir James McCusker Alzheimer’s Disease Research Unit, Perth, Australia; 3National Institute of Radiological Science, Tokyo, Japan; 4Royal Prince Alfred Hospital, Sydney, Australia; 5The University of Milan, Milan, Italy; 6Sir James McCusker Alzheimer’s Disease Research Unit (Hollywood Private Hospital), Perth, Australia; 7Edith Cowan University, Perth, Australia. Contact e-mail: [email protected] Background: Ligands
of the translocator protein (TSPO) have been identified as promising candidate therapeutic agents for several neurodegenerative disorders due to their ability to enhance neurosteroidogenesis. We have previously
Podium Presentations: Sunday, July 19, 2015
demonstrated that the classic TSPO ligands, Ro5-4864 and PK11195, increase brain steroid levels, reduce Ab accumulation, and improve cognition in a mouse model of AD. Here we evaluated the steroidogenic efficacy and acute behavioral effects of three TSPO imidazopyridine ligands, CLINDE, PBR175, and PBR162, which we have previously shown to be non-toxic in vitro. CLINDE, which exhibited the most favorable behavioral and pharmacokinetic profile, was investigated further for its specificity and binding affinity in human brain. Methods: The acute behavioural effects of the three novel TSPO ligands were compared with Ro5-4864, in 3 month old castrated C57BL/6J mice. Two hours after ligand injection (3 mg/kg i.p.), anxiety-, depression-, and memory-related behaviors were assessed in the elevated-plus maze, open field maze, tail-suspension test, and object recognition tests respectively. Brain steroids levels were measured by LC-MS/MS. To determine if the behavioral effects of TSPO ligands were mediated via increased neurosteroidogenesis, mice were pretreated with a steroidogenesis inhibitor, aminogluthetimide (10mg/ kg). The pharmacokinetic properties of the novel ligands were assessed by competitive PET imaging [11C]PK-11195. The specificity of action of CLINDE was determined in TSPO knockout mice, and the affinity for TSPO (Ki value) in human brain homogenate was investigated in vitro by [11C] PK-11195 binding assay. Results: CLINDE and PBR175 improved learning and memory performance equally well as Ro5-4864. These improvements were completely ablated by aminogluthetimide, confirming that the beneficial effects were mediated through an increase in neurosteroidogenesis. Anxietyand depression-related behaviors were unaffected by the TSPO ligands. Competitive PET studies indicated that CLINDE showed the most long lasting binding to TSPO. The specificity of behavioral effects of CLINDE was confirmed. The affinity of CLINDE in high-affinity binder (HAB) and low-affinity binder (LAB) subjects were 5.5 and 29.7 respectively. Conclusions: These findings indicate that CLINDE and PBR175 rapidly promote neurosteroidogenesis, thereby enhancing learning and memory in vivo. These second generation TSPO ligands are promising therapeutic candidates with improved pharmacokinetic properties compared to classic TSPO ligands.
O1-11-03
MODULATING CHEMOKINE SIGNALING IN PRECLINICAL ALZHEIMER’S DISEASE MODELS
Todd Golde1, Yona Levites1, Pedro E. Cruz1, Awilda M. Rosario1, Paramita Chakrabarty1, Corey Moran1, Xuefei Liu1, Carolina CeballosDiaz1, Brenda Moore1, Nathan D. Price2, Corey Funk2, 1University of Florida, Gainesville, FL, USA; 2The Institute for Systems Biology, Seattle, WA, USA. Contact e-mail: [email protected] Background: Most disease modifying therapies in AD target the
protein aggregation process that is thought to trigger the disease or involve some form of neuroprotective strategy. It has been shown that changes in transcriptional networks of innate immunity genes are likely to play a key role in AD. We have been using custom Nanostring array to assess changes in innate immune gene expression in the brains of APP and Tau transgenic mouse models. As expected, these experiments demonstrated extensive innate immune activation in transgenic mice. Thus, we hypothesize that select innate immune signaling factors elevated in AD and in AD mouse models, will have an effect on cognition and amyloid deposition when overexpressed in the brain following
P157
AAV delivery. Methods: We cloned an array of chemokines as well as truncated chemokines that are known for their dominant negative effects into pAAV. Then we expressed these chemokines in the brains of newborn transgenic CRND8 mice, using of somatic brain transgenic approach. Effects on cognition and amyloid pathology are assessed at three and six month of age. In the first part of the study the chemokines are assessed for their effects on behavior in non-transgenic mice, by fear conditioning testing. The second part focuses on chemokines effects on amyloid pathology in CRDN8 mice. Amyloid levels are assessed by biochemical and immunohistochemical methods. Results: First we have assessed for effects of chemokines overexpression on behavior in non-transgenic mice. CXCL10 overexpression resulted in a trend toward memory impairment in three month old non-transgenic CRND8 mice as assessed by fear conditioning testing. In contrast, amyloid pathology in 6 month old CRND8 mice overexpressing CXCL10, was reduced as compared to control, PBS injected mice. Currently we are assessing effects of overexpression and downregulation of additional chemokines on behavior and amyloid pathology in CRND8 mouse model. Additionally, RNAsec analysis from mouse and human studies is underway. Conclusions: These studies provide an insight on effects of manipulation of the innate immunity on amyloid pathology formation and deposition in CRND8 mice.
O1-11-04
TARGETING LEUKOCYTE INTEGRINS HAS THERAPEUTIC EFFECT IN ALZHEIMER’S-LIKE DISEASE
Gabriela Constantin, Enrica Caterina Pietronigro, Elena Zenaro, Gennj Piacentino, Vittorina Della Bianca, Maria Giovanna Rossi, Carlo Laudanna, University of Verona, Verona, Italy. Contact e-mail: [email protected] Background: Vascular inflammation and a dysfunctional bloodbrain-barrier have been implicated in the pathogenesis of Alzheimer’s disease. However, the role of leukocyte trafficking mechanisms in Alzheimer’s disease in the induction of neuropathological changes and memory deficit is unclear. Methods: We carried out two-photon laser-scanning microscopy (TPLSM) experiments in the brain of mice with five familial Alzheimer’s disease (5xFAD) mutations presenting amyloid pathology, and 3xTgAD mice with both amyloid and tau pathology and observed that fluorescently labeled neutrophils and activated lymphocytes adhere to the vascular endothelium and migrate into the brain parenchyma in these animals. Results: Blocking monoclonal antibodies to LFA-1 (alphaLbeta2) and VLA-4 (alpha4beta1) integrins significantly inhibited neutrophil and lymphocyte adhesion in brain vessels, suggesting that leukocyte integrins play a role in leukocyte extravasation in Alzheimer’s disease models. In addition, our TPLSM data showed that leukocytes from LFA1 deficient mice are completely unable to adhere or crawl in the blood vessels and thus to transmigrate in the brain parenchyma of Alzheimer’s disease mice. LFA1 or VLA-4 inhibition using monoclonal antibodies clearly improved memory function compared to mice treated with a control antibody, restoring performance to levels comparable with wild-type age-matched littermates in Y maze and contextual fear conditioning tests. The role of LFA-1 integrin was confirmed by crossing 3xTg-AD animals with the LFA-1-deficient Itgal-/- strain. We found that the 3xTgAD mice lacking LFA-1 integrin showed improved memory in cognitive tests compared to wild-type animals. These findings