Skip to main content
PMC home page
The FASEB Journal logoLink to The FASEB Journal
. 2010 Dec;24(12):4639–4647. doi: 10.1096/fj.10-161471

Behavioral deficits and progressive neuropathology in progranulin-deficient mice: a mouse model of frontotemporal dementia

Fangfang Yin *,‡, Magali Dumont †,1, Rebecca Banerjee †,1, Yao Ma *,§,1, Huihong Li *, Michael T Lin †, M Flint Beal †, Carl Nathan *,‡, Bobby Thomas †, Aihao Ding *,‡,2
PMCID: PMC2992364  PMID: 20667979

Abstract

Progranulin haploinsufficiency causes frontotemporal dementia with tau-negative, ubiquitin-positive neuronal inclusion pathology. In this study, we showed that progranulin-deficient mice displayed increased depression- and disinhibition-like behavior, as well as deficits in social recognition from a relatively young age. These mice did not have any deficit in locomotion or exploration. Eighteen-month-old progranulin-deficient mice demonstrated impaired spatial learning and memory in the Morris water maze. In addition to behavioral deficits, progranulin-deficient mice showed a progressive development of neuropathology from 12 mo of age, including enhanced activation of microglia and astrocytes and ubiquitination and cytoplasmic accumulation of phosphorylated TDP-43. Thus, progranulin deficiency induced FTD-like behavioral and neuropathological deficits. These mice may serve as an important tool for deciphering underlying mechanisms in frontotemporal dementia.—Yin, F., Dumont, M., Banerjee, R., Ma, Y., Li, H., Lin, M. T., Beal, M. F., Nathan, C., Thomas, B., Ding, A. Behavioral deficits and progressive neuropathology in progranulin-deficient mice: a mouse model of frontotemporal dementia.

Keywords: neurodegeneration, TDP-43, ubiquitin, transgenic mice

Progranulin (PGRN), also known as proepithelin, acrogranin, or prostate cancer (PC) cell-derived growth factor (1–3), is a secreted pleiotropic protein that is composed of 7.5 tandem repeats of a 6-kDa granulin/epithelin (GRN/EPI) motif. Proteolytic cleavage of PGRN gives rise to functionally active GRNs or EPIs. PGRN is involved in a number of physiological or pathogenic processes, including embryonic development, wound healing, inflammation, and tumorigenesis (2–4). In the brain, PGRN is mainly expressed by neurons and microglia (3, 5). Little is known about its function in the central nervous system. Previous studies suggested that PGRN may act as a neurotrophic factor in that recombinant PGRN could promote the growth of PC12 cells, a pheochromocytoma-derived neuronal cell line (3), and GRN E, one of 7 granulins, improved survival and neurite growth of motor neurons in culture (6). We recently reported that PGRN deficiency in mice was associated with a hyperinflammatory phenotype in activated macrophages and microglia, which, in turn, accelerated the damage of neurons (7).

Loss-of-function mutations in the progranulin gene were recently identified to cause tau-negative, ubiquitin-positive frontotemporal dementia (FTD) (8, 9), the second most common dementia in people under the age of 65 after Alzheimer's disease (AD) (10). FTD is characterized by relatively selective atrophy of frontal and/or temporal cortices. Clinically, FTD patients manifest progressive changes in behavior and personality characterized by early decline in social and personal interaction and emotional blunting, disinhibition, language disorders, and in later stages, more general cognitive decline (11). No animal model is currently available for PGRN haploinsufficiency-related FTD.

We have created a PGRN-deficient mouse model with the Cre-LoxP system (7). In the current study, we analyzed behavior and neuropathology in these mice from 1 to 18 mo of age. We found that PGRN-deficient mice display behavioral deficits in social recognition and depression- and anxiety-like behaviors. Moreover, PGRN-deficient mice developed cognitive deficits that progressed with aging. These were associated with neuropathological changes, such as accumulation of ubiquitin and cytosolic phosphorylated TDP-43 in the hippocampus. Thus, PGRN-deficient mice can serve as a model for studying some aspects of the behavioral and neuropathological features seen in FTD.

MATERIALS AND METHODS

Mice

Progranulin-deficient mice and their wild-type (WT) littermates were generated as described previously (7). Mice were bred and maintained in pathogen-free conditions in the animal facilities of Weill Cornell Medical College. All animal experiments were approved by the institutional animal care and use committee.

Open-field test

The open-field apparatus (45×45 cm, wall height 20 cm) was made of opaque black plastic. Mice were placed in one corner, and the total distance moved was recorded in a 5-min session daily for 3 d using a video tracking system (Ethovision 3.0; Noldus Technology, Attleborough, MA, USA). The apparatus was cleaned with 40% ethanol after each mouse entry.

Morris water maze test

The Morris water maze consisted of a basin (diameter 120 cm, wall height 60 cm) filled with water (22°C) made opaque by the addition of nontoxic and odor-free white tempera paint. The escape platform was made of transparent plastic. The pool was placed in a room with various extramaze visual cues, such as light fixtures and signs. Mice were placed next to and facing the wall successively in north, east, south, and west positions, with the escape platform hidden 1 cm beneath the water level in the middle of the northwest (NW) quadrant. Latencies before reaching the platform were recorded in 4-trial sessions every day for 5 d with a 40-min intertrial interval using Ethovision 3.0 (Noldus Technology). After each swim, mice were kept dry in a plastic holding cage filled with paper towels. Whenever the mice failed to reach the escape platform within the 1-min cutoff period, they were placed on it for 5 s.

One hour after the acquisition phase, a probe trial was conducted by removing the platform from the pool, placing the mouse next to and facing the north side. Time spent in the previously correct quadrant was measured in a single 1-min trial. The visible platform version was also evaluated, with the escape platform lifted at water level. A pole was inserted on top of the escape platform as a viewing aid. Escape latencies were measured for 4 trials/day for 2 d with a 1-min cutoff period and a 40-min intertrial interval. The location of the platform was changed between trials.

Accelerated rotarod test

Motor coordination was evaluated in the accelerated rotarod (Economex accelerated rotarod; Columbus Instruments, Columbus, OH, USA). The beam of the apparatus (diameter 4 cm, width 8 cm, height 38 cm) was made of ribbed plastic, and plates were flanked on either side to prevent escape. Mice were placed on the top of the revolving beam for 4 successive trials/d for 2 d, with 20-min intertrial intervals. The rod was accelerated gradually from 4 to 28 rpm over 2 min. Latencies before falling from the rod were recorded.

Tail suspension test

Mice were suspended 30 cm from the floor with tails taped onto a wood surface. Each mouse was given one 6-min trial and scored for duration of immobility (defined as the absence of all movement except for respiration). Mice that climbed up their tails for >20% of the time were eliminated from the test.

Forced swimming test

Mice were placed in a glass cylinder (height 25 cm, diameter 14 cm) containing 14 cm water (22°C). The time they stayed immobile in a 7-min session was recorded. Immobility was defined as the absence of all movements except motions required to keep the head above water.

Elevated plus maze

The elevated plus maze is a 4-arm maze elevated 39 cm above the floor. The 4 arms intersect and form a plus sign (dimension of each arm: length 30 cm, width 5 cm; height from floor: 39 cm; center region: 5×5 cm2). Two of the arms are closed on 3 sides by 15-cm-high walls, and the other two are open. Animals were placed in the center of the apparatus and allowed to freely explore the maze for 5 min. Time spent in open arms were measured. All arms were cleaned with 40% ethanol after each mouse entry.

Social behavior test

The apparatus was a rectangular, 3-chambered polycarbonate box. Three chambers were connected with retractable open doorways on 2 dividing walls. Chambers of the apparatus were cleaned with 40% ethanol and dried with paper towels between each trial. The test was comprised of 3 major steps, as described previously (12). 1) For the habituation step, the test mouse was placed into the middle chamber and allowed to explore freely for 10 min. Time spent in each chamber was recorded to measure the side preference bias. Each of the 2 sides contained an inverted empty wire cup. 2) For the sociability step, after the habituation period, the test mouse was enclosed in the middle chamber, and an unfamiliar mouse (stranger 1) was introduced into one of the empty wire cups. Doors were reopened and time spent sniffing each wire cup was recorded for 10 min. 3) After the 10-min social test, the preference for social novelty was assessed, in which the test mouse was enclosed again in the middle chamber, and a new mouse (stranger 2) was introduced into the empty wire cup. The test mouse was then released, and time spent sniffing each wire cup was measured. Female sibling mice were used as stranger 1 and stranger 2 in the study.

Olfactory sensitivity test

Olfactory discrimination was tested according to the procedures of Witt et al. (13). In brief, clear cages (12×12 inches, wall height 8 inches) with no bedding were lined up in a biosafety cabinet without lighting. Opaque filter papers were inserted between cages to set up partitions. Each cage was covered with an opaque filter cage cover. The mice were offered water only for 12 h before testing. A naive mouse was placed in 3 cages sequentially for habituation for 15 min each. The testing mouse was then transferred into the testing cage, and a round filter paper (diameter 70 mm), spotted with water, was placed in the center of the cage for 3 min. The time that the mouse sniffed the paper (defined as distance between mouth and paper <1 mm) was recorded. A second filter paper spotted with sesame oil was then introduced into the cage to replace the first filter, and the sniffing time was recorded again for 3 min. Each filter paper was used only once and was blot-dried with Kimwipes (Kimberley-Clark, Irving, TX, USA) before use. The cages were cleaned with an odorless ready-to-use disinfectant spray (Quatricide TB; Pharmacal, Waterbury, CT, USA) followed by water and dried with paper towels between each trial.

Immunohistochemistry

WT and PGRN-deficient mice (3, 12, and 18 mo old) were transcardially perfused under pentobarbital sodium anesthesia with ice-cold 0.9% saline followed by 4% paraformaldehyde (PFA) in PBS, pH 7.4. The brains were postfixed in 4% PFA for 24 h and cryopreserved in 30% sucrose/PBS for 48 h. Coronal brain cryosections (40 μm) encompassing the hippocampus, cortex, and thalamus were processed free-floating for CD68, GFAP, phospho-TDP-43, and ubiquitin immunohistochemistry, as described previously (7). Briefly, sections were rinsed in PBS and incubated in 3% hydrogen peroxide/10% methanol solution for 10 min to quench endogenous peroxidase activity. Sections were permeabilized/blocked in 10% normal goat serum (NGS)/0.1% Triton X-100/PBS for 1 h at room temperature. Sections were incubated overnight at 4°C with following primary antibodies in PBS containing 2% NGS/0.01% Triton X-100: rat monoclonal anti-CD68 (1:500; AbD Serotec, Raleigh, NC, USA), mouse monoclonal anti-ubiquitin (1:50,000; Millipore, Bedford, MA, USA), rabbit polyclonal anti-GFAP (1:2,000; Dako Cytomation, Glostrup, Denmark), mouse monoclonal anti-phospho-TDP-43 (pS409/410; 1:500). Biotinylated secondary antibodies (Jackson ImmunoResearch Laboratories, Bar Harbor, ME, USA) were used appropriately before incubation with streptavidin ABC solution (Vector Laboratories, Burlingame, CA, USA). Immunostaining was visualized by diaminobenzidine (Sigma-Aldrich, St. Louis, MO, USA) chromogen. Sections mounted on slides were counterstained with cresyl violet acetate or thionin (Sigma-Aldrich). Sections were dehydrated and cover slipped with cytoseal (Thermo Scientific, Barrington, IL, USA). Digital images were captured with a Coolpix 5000 camera (Nikon, Tokyo, Japan).

Quantification of microglial activation and GFAP-reactive cells

Cell counts based on activated morphology of CD68+ microglial cells and GFAP+ astrocytes (7) were performed on images captured from 3 coronal sections/mouse encompassing the hippocampus, cortex, and thalamus. Quantitative analysis (cells/mm2) was conducted using Image J software (National Institutes of Health, Bethesda, MD, USA).

Statistical analyses

For behavioral study, intergroup differences were evaluated by ANOVA with repeated measures and unpaired t tests. For others, 2-group comparisons were analyzed by the 2-tailed Student's t test for independent samples. Values of P < 0.05 were considered statistically significant. All data are presented as means ± se.

RESULTS

Normal locomotor and exploratory behavior in PGRN-deficient mice

As reported, PGRN-deficient mice develop normally and are fertile (7). To assess locomotor and exploratory activity, PGRN-deficient mice and their WT littermates were examined in open-field and accelerated rotarod tests at 5, 12, and 18 mo of age. In the open field, no abnormality was observed in PGRN-deficient mice when we recorded the total distance traveled for 3 consecutive days (Fig. 1A). In the accelerated rotarod test, we recorded the latency before falling from the rod for 2 consecutive days. No difference in motor performance was found between WT and PGRN-deficient mice (Fig. 1B). These results suggest that PGRN-deficient mice display normal locomotor and exploratory activity.

Figure 1.

Figure 1.

Open in a new tab

Normal motor behavior in PGRN-deficient mice. A) Open field: WT and PGRN-deficient (KO) mice were tested at 5 (n=15/group), 12 (n=15/ group), and 18 (n=10/group) mo of age in the open-field test. Distances moved during 3 consecutive days are shown. B) Accelerated rotarod: WT and KO mice were tested at 5 (n=15/group), 12 (n=15/group), and 18 (n=10/group) mo of age in the accelerated rotarod. Results show latencies before falling. Results are expressed as means ± se.

Increased depression- and disinhibition-like behavior of PGRN-deficient mice

Contrary to AD, behavioral and personality changes often precede cognitive alterations in FTD. In the early stage of the disease, loss of initiative and neglect of personal hygiene resemble symptoms of depression. Therefore, we tested PGRN-deficient mice in 2 commonly used depression-like tests, tail suspension and forced swimming. In both tests, PGRN-deficient mice remained immobile for significantly longer periods than WT mice (Fig. 2A, B) at 4, 12, and 18 mo of ages, indicating that PGRN-deficient mice develop depression-like behavior starting as early as 4 mo of age.

Figure 2.

Figure 2.

Open in a new tab

Emotional behavior deficit in PGRN-deficient mice. A) Depression test: WT and PGRN-deficient (KO) mice at 4 (n=15/group), 12 (n=15/group), and 18 (n=10/group) mo of age were suspended by the tail (left panel) or placed in a forced swimming tank (right panel). Time stayed immobile was recorded, and results were expressed as means ± se. P value, Student's t test. B) Anxiety test: Wild-type (WT) and PGRN-deficient (KO) mice at 3 (n=15/group), 12 (n=15/group), and 18 (n=10/group) mo of age were subjected to the elevated plus maze test. Time spent in the open arms or the closed arms were recorded; results are expressed as percentage of time spent in the open arms. Results are expressed as means ± se. Values of P calculated by Student's t test.

FTD patients were also found to have significantly higher levels of disinhibition than AD patients (14). In the elevated plus maze test, we found that 3-mo-old PGRN-deficient mice were disinhibited, as they spent more time in the open arms than their WT littermates. There was also a trend toward an increase in time spent in the open arms of the maze at 12 and 18 mo of age for PGRN-deficient mice (Fig. 2B).

Recognition deficits in PGRN-deficient mice

FTD is characterized by a preponderance of abnormalities in social behavior rather than memory, especially in the early stages of the disease. Hence, we tested the social behavior of PGRN-deficient mice at 1, 7, and 18 mo of age. In the social recognition test, PGRN-deficient mice displayed less preference for a container holding a mouse over an empty container and less preference for an unfamiliar mouse over a familiar one than the WT mice. This deficit was seen at the age of 1 mo and progressed with aging (Fig. 3A). To ascertain that defects of social behavior in PGRN-deficient mice were not due to abnormal olfactory function, we performed an olfactory discrimination test. We analyzed the preference for sesame oil over water of WT and PGRN-deficient mice after deprivation of food overnight (Fig. 3B). No olfactory abnormality was found in PGRN-deficient mice at 2 and 6 mo of age. However, at 18 mo of age, PGRN-deficient mice showed a diminished preference toward sesame oil, as compared with age-matched WT mice. This finding indicates that PGRN-deficiency could cause olfactory impairment in the old but not young mice (Fig. 3B). Thus, PGRN-deficient mice have impaired social interaction, consistent with clinical features of FTD in humans.

Figure 3.

Figure 3.

Open in a new tab

Social recognition deficit in PGRN-deficient mice. A) Social recognition: WT and PGRN-deficient (KO) mice were tested at 1 (n=15/group), 7 (n=15/group), and 18 (n=10/group) mo of age. In the first 10 min (top upper panel), time spent sniffing an empty wire container (white) or an identical container holding an unfamiliar mouse (gray, stranger 1) was recorded. In the next 10 min (bottom panel), time spent sniffing the container with the now familiar stranger 1 (gray) or the container with a new mouse (black, stranger 2) was recorded. B) Olfactory discrimination: WT and PGRN-deficient (KO) mice were subjected to olfactory discrimination test at 2 (n=15/group), 6 (n=14/group), and 18 (n=10/group) mo of age. Time spent sniffing a filter paper spotted either with water or sesame oil was recorded for 3 min. Results are expressed as means ± se. Values of P calculated by Student's t test.

Impaired cognitive behavior in old PGRN-deficient mice

FTD patients usually do not display cognitive deficits until later stages of the disease (10). Consistent with this observation, PGRN-deficient mice did not show significant learning impairment in the Morris water maze until 18 mo of age (Fig. 4A, right panel), although moderate impairment of learning could be detected in these mice at 12 mo of age (Fig. 4A, middle panel). In the probe trial, only the 18-mo-old PGRN-deficient mice showed a significant reduction in the time spent in the target quadrant and in the number of quadrant crosses compared to age-matched WT mice (Fig. 4B). Thus, 18-mo-old PGRN-deficient mice had spatial learning and memory deficits. No abnormality was observed in the visible platform version of the Morris water maze in PGRN-deficient mice (data not shown).

Figure 4.

Figure 4.

Open in a new tab

Cognitive deficit in old PGRN-deficient mice. A) Morris water maze hidden platform: WT and PGRN-deficient (KO) mice at 5 (n=15/group), 12 (n=15/group), and 18 (n=10/group) mo of age were trained to locate the hidden platform for 5 consecutive days. Time spent finding the platform was recorded each day. B) Morris water maze probe trial: On d 5, mice were subjected to the probe trial without platform, and percentage of time spent in the target quadrant (left panel) and number of target quadrant crosses (right panel) were measured. Results are expressed as means ± se. Values of P calculated by Student's t test.

Development of neuropathology in PGRN-deficient mice

We have reported that PGRN-deficient mice displayed an augmented age-dependent activation of microglia and astrocytes when compared with wild-type mice at 18 mo of age (7). In the same study, we also showed enhanced hippocampal ubiquitin immunostaining and increased phosphorylation of TDP-43 in the hippocampus and thalamus of old PGRN-deficient mice. Some of these results were recently confirmed by studies with independently generated PGRN-knockout mice (15). To determine whether the neuropathology observed was age dependent, we performed the same assays side-by-side using brain sections from 3-, 12- and 18-mo-old mice, both wild-type and PGRN-deficient. Immunostaining for myeloid antigen CD68, a marker of activated microglia, and glial fibrillary acidic protein (GFAP), an astrocyte marker, showed that microglia (Fig. 5) and astrocytes (Fig. 6) were already activated in 12-mo-old PGRN-deficient brain, and the activation was further augmented at 18 mo of age. Similarly, ubiquitination and phosphorylation of TDP-43 were observed in the old PGRN-deficient brain (Figs. 7 and 8). Thus, neuropathology in PGRN-deficient mice progressed with age.

Figure 5.

Figure 5.

Open in a new tab

Activation of microglial in PGRN-deficient mice. A–C) Coronal sections of hippocampus (A), cortex (B), and thalamus (C) from age-matched wild-type (WT) and PGRN-deficient (KO) mice (n=5) were immunostained for CD68 expression. D–F) Quantitative analysis of CD68+, expressed as cells per square millimeter. Results are expressed as means ± se. *P < 0.0001 vs. WT; Student's t test. Scale bars = 100 μm (A), 200 μm (B, C).

Figure 6.

Figure 6.

Open in a new tab

Activation of astrocytes in PGRN-deficient mice. A–C) Coronal sections of hippocampus (A), cortex (B), and thalamus (C) from age-matched WT and PGRN-deficient (KO) mice (n=5) were immunostained for GFAP expression. D–F) Quantitative analysis of GFAP+, expressed as cells per square millimeter. Results are means ± se. *P < 0.0001 vs. WT; Student's test. Scale bars = 100 μm (A), 200 μm (B, C).

Figure 7.

Figure 7.

Open in a new tab

Cytosolic phosphorylated TDP-43 accumulation in PGRN-deficient mice. Coronal sections of hippocampus (A) and thalamus (B, C) from age-matched WT and PGRN-deficient (KO) mice (n=5) were immunostained for phosphorylated TDP-43. Solid arrowheads indicate cytosolic accumulation of phosphorylated TDP-43. Scale bars = 100 μm (A), 200 μm (B), 10 μm (C).

Figure 8.

Figure 8.

Open in a new tab

Hippocampal ubiquitination in PGRN-deficient mice. Coronal hippocampal sections from 3, 12, and 18 mo-old WT and PGRN-deficient (KO) mice (n=5) were stained for antiubiquitin reactivity. Representative images demonstrate increased ubiquitination in 12- and 18-mo-old KO mice. Scale bar = 100 μm.

DISCUSSION

FTD is a group of clinically related syndromes caused by progressive degeneration of the frontal and/or temporal lobes of the brain. After Alzheimer's disease, FTD is one of the most frequent causes of dementia. Signs of frontal and temporal lobe impairment in FTD include behavioral changes such as disinhibition, inappropriate social behavior, depression, and apathy, as well as executive dysfunctions such as cognitive decline, usually late in the disease.

Loss-of-function mutations in the progranulin gene were recently identified as the cause of tau-negative, ubiquitin-positive FTD (8, 9). To investigate the role of PGRN in FTD, we created PGRN-deficient mice. In a previous study, we found that PGRN-deficient mice responded to infection with exaggerated inflammation in that their macrophages produced enhanced levels of proinflammatory mediators systemically. These mice also had an impaired ability to clear Listeria infection (7). Neuropathological analysis revealed increases in ubiquitination and phosphorylation of TAR DNA binding protein 43 (TDP-43) and augmented activation of microglia and astrocytes in the brains of aged PGRN-deficient mice (7). In this study, we assessed the behavioral profile of PGRN-deficient mice from 1 to 18 mo of age. We found that PGRN-deficient mice showed impairment in social recognition tasks. They also showed increased depression-like behaviors and disinhibition. Another study using PGRN-knockout mice also reported alterations in anxiety-like behavior that was modulated by gender (16). These authors later found that there was a link between such behavioral changes and the volume of the locus coeruleus (17). However, we did not observe gender-dependent behavioral changes. In our study, behavioral deficits appeared early in the disease (at 1 mo of age) and were still present at 18 mo of age. Our findings are consistent with the behavioral and personality changes observed in FTD patients. For cognitive skills, we evaluated spatial learning and memory. At a late stage in the disease, 18-mo-old PGRN-deficient mice showed a cognitive decline as evidenced by poor performances in the acquisition period and the probe trial of the Morris water maze. At 12 mo of age, PGRN-deficient mice had a moderate spatial learning deficit. Thus, as in FTD, PGRN-deficient mice had late-onset cognitive decline. Therefore, PGRN-deficient mice model several important behavioral features of FTD. Interestingly, the appearance of cognitive deficits was associated with the presence of neuropathological features. Indeed, we found that PGRN deficiency induced progressive gliosis and ubiquitination and phosphorylation of TDP-43, especially in the hippocampus.

FTD patients usually do not show behavioral abnormalities until midlife, when frontotemporal cerebral atrophy becomes prominent. Other neuropathologic changes, such as the appearance of neuronal inclusions immunoreactive for ubiquitin and phosphorylated TDP-43, were examined and detected after behavioral abnormalities were diagnosed (18–20). PGRN-deficient mice did not develop cerebral atrophy. Their neuropathology progressed with age, but impairment in social recognition, depression-like behavior, and disinhibition were detected early. Some patients with FTD die prematurely, but PGRN-deficient mice survive into late adulthood and no reduction in their life span has yet been noted. Some of the differences between people with FTD and PGRN-deficient mice may reflect a dose effect. FTD patients are PGRN-haplosufficient, but homozygous PGRN-knockout mice express no PGRN. In addition, mechanisms underlying development of behavioral abnormalities are not likely to be identical between human and mouse. Nonetheless, it is clear that PGRN deficiency leads to development of FTD-like abnormalities in the mouse.

One plausible mechanism underlying PGRN-deficiency-linked behavioral deficits is that PGRN′s anti-inflammatory action may be indispensable for a balanced immune response in the brain. We recently demonstrated that PGRN-deficient mice displayed exaggerated inflammatory responses and impaired host defense (7). This may result in pathological changes such as ubiqutinopathy and TDP-43 proteinopathy in the brain, as reported by Yin et al. (7) and confirmed in this study. There is mounting evidence indicating a causal relationship between inflammation or chronic infection and psychiatric disorders such as depression (21–25). Studies from animal models also suggest that prolonged peripheral infections in old mice could be directly associated with development of cognitive decline and behavioral abnormalities (26). Alternatively, the neurotrophic nature of PGRN and its granulin products may protect neurons from various insults, including metabolic stresses and inflammatory responses (3, 6, 7, 27). Deficiency of PGRN may thus render neurons more vulnerable to develop pathological changes, which, in turn, can result in behavioral abnormalities.

To our knowledge, this work is the first to demonstrate that PGRN-deficient mice recapitulate several major behavioral hallmarks of FTD. Thus, PGRN-deficient mice may serve as a tool for studying mechanism(s) through which loss-of-function mutations in PGRN precipitate FTD-like symptoms and for developing therapeutic strategies for the treatment of this disease, perhaps including anti-inflammatory therapy.

Acknowledgments

This work was supported by National Institutes of Health grants GM061710 and AI030165 (to A.D.), NS060885, NS062165 (to B.T.), a predoctoral fellowship from the Cancer Research Institute (to F.Y.), and an Appel Established Investigatorship (to C.N.). The Department of Microbiology and Immunology is supported by the William Randolph Hearst Foundation. The authors thank Dr. Haruhiko Akiyama, Masato Hasegawa, and Tetsuaki Arai (Tokyo Institute of Psychiatry, Tokyo, Japan) for antibody against phosphorylated TDP-43 (pS409/410).

REFERENCES

  • 1.Baba T., Hoff H. B., 3rd, Nemoto H., Lee H., Orth J., Arai Y., Gerton G. L. (1993) Acrogranin, an acrosomal cysteine-rich glycoprotein, is the precursor of the growth-modulating peptides, granulins, and epithelins, and is expressed in somatic as well as male germ cells. Mol. Reprod. Dev. 34, 233–243 [DOI] [PubMed] [Google Scholar]
  • 2.He Z., Bateman A. (2003) Progranulin (granulin-epithelin precursor, PC-cell-derived growth factor, acrogranin) mediates tissue repair and tumorigenesis. J. Mol. Med. 81, 600–612 [DOI] [PubMed] [Google Scholar]
  • 3.Daniel R., Daniels E., He Z., Bateman A. (2003) Progranulin (acrogranin/PC cell-derived growth factor/granulin-epithelin precursor) is expressed in the placenta, epidermis, microvasculature, and brain during murine development. Dev. Dyn. 227, 593–599 [DOI] [PubMed] [Google Scholar]
  • 4.Zhu J., Nathan C., Jin W., Sim D., Ashcroft G. S., Wahl S. M., Lacomis L., Erdjument-Bromage H., Tempst P., Wright C. D., Ding A. (2002) Conversion of proepithelin to epithelins: roles of SLPI and elastase in host defense and wound repair. Cell 111, 867–878 [DOI] [PubMed] [Google Scholar]
  • 5.Ahmed Z., Mackenzie I. R., Hutton M. L., Dickson D. W. (2007) Progranulin in frontotemporal lobar degeneration and neuroinflammation. J. Neuroinflammation 4, 7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Van Damme P., Van Hoecke A., Lambrechts D., Vanacker P., Bogaert E., van Swieten J., Carmeliet P., Van Den Bosch L., Robberecht W. (2008) Progranulin functions as a neurotrophic factor to regulate neurite outgrowth and enhance neuronal survival. J. Cell Biol. 181, 37–41 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Yin F., Banerjee R., Thomas B., Zhou P., Qian L., Jia T., Ma X., Ma Y., Iadecola C., Beal M. F., Nathan C., Ding A. (2010) Exaggerated inflammation, impaired host defense, and neuropathology in progranulin-deficient mice. J. Exp. Med. 207, 117–128 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Baker M., Mackenzie I. R., Pickering-Brown S. M., Gass J., Rademakers R., Lindholm C., Snowden J., Adamson J., Sadovnick A. D., Rollinson S., Cannon A., Dwosh E., Neary D., Melquist S., Richardson A., Dickson D., Berger Z., Eriksen J., Robinson T., Zehr C., Dickey C. A., Crook R., McGowan E., Mann D., Boeve B., Feldman H., Hutton M. (2006) Mutations in progranulin cause tau-negative frontotemporal dementia linked to chromosome 17. Nature 442, 916–919 [DOI] [PubMed] [Google Scholar]
  • 9.Cruts M., Gijselinck I., van der Zee J., Engelborghs S., Wils H., Pirici D., Rademakers R., Vandenberghe R., Dermaut B., Martin J. J., van Duijn C., Peeters K., Sciot R., Santens P., De Pooter T., Mattheijssens M., Van den Broeck M., Cuijt I., Vennekens K., De Deyn P. P., Kumar-Singh S., Van Broeckhoven C. (2006) Null mutations in progranulin cause ubiquitin-positive frontotemporal dementia linked to chromosome 17q21. Nature 442, 920–924 [DOI] [PubMed] [Google Scholar]
  • 10.Neary D., Snowden J. S., Gustafson L., Passant U., Stuss D., Black S., Freedman M., Kertesz A., Robert P. H., Albert M., Boone K., Miller B. L., Cummings J., Benson D. F. (1998) Frontotemporal lobar degeneration: a consensus on clinical diagnostic criteria. Neurology 51, 1546–1554 [DOI] [PubMed] [Google Scholar]
  • 11.Viskontas I. V., Possin K. L., Miller B. L. (2007) Symptoms of frontotemporal dementia provide insights into orbitofrontal cortex function and social behavior. Ann. N. Y. Acad. Sci. 1121, 528–545 [DOI] [PubMed] [Google Scholar]
  • 12.Moy S. S., Nadler J. J., Young N. B., Perez A., Holloway L. P., Barbaro R. P., Barbaro J. R., Wilson L. M., Threadgill D. W., Lauder J. M., Magnuson T. R., Crawley J. N. (2007) Mouse behavioral tasks relevant to autism: phenotypes of 10 inbred strains. Behav. Brain Res. 176, 4–20 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Witt R. M., Galligan M. M., Despinoy J. R., Segal R. (2009) Olfactory behavioral testing in the adult mouse. J. Vis. Exp. 23, 949. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.De Vugt M. E., Riedijk S. R., Aalten P., Tibben A., van Swieten J. C., Verhey F. R. (2006) Impact of behavioural problems on spousal caregivers: a comparison between Alzheimer's disease and frontotemporal dementia. Dement. Geriatr. Cogn. Disord. 22, 35–41 [DOI] [PubMed] [Google Scholar]
  • 15.Ahmed Z., Sheng H., Xu Y. F., Lin W. L., Innes A. E., Gass J., Yu X., Hou H., Chiba S., Yamanouchi K., Leissring M., Petrucelli L., Nishihara M., Hutton M. L., McGowan E., Dickson D. W., Lewis J. (2010) Accelerated lipofuscinosis and ubiquitination in granulin knockout mice suggests a role for progranulin in successful aging. Am. J. Pathol. 177, 311–324 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Suzuki M., Lee H. C., Kayasuga Y., Chiba S., Nedachi T., Matsuwaki T., Yamanouchi K., Nishihara M. (2009) Roles of progranulin in sexual differentiation of the developing brain and adult neurogenesis. J. Reprod. Dev. 55, 351–355 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Chiba S., Matsuwaki T., Yamanouchi K., Nishihara M. (2009) Alteration in anxiety with relation to the volume of the locus ceruleus in progranulin-deficient mice. J. Reprod. Dev. 55, 518–522 [DOI] [PubMed] [Google Scholar]
  • 18.Josephs K. A., Ahmed Z., Katsuse O., Parisi J. F., Boeve B. F., Knopman D. S., Petersen R. C., Davies P., Duara R., Graff-Radford N. R., Uitti R. J., Rademakers R., Adamson J., Baker M., Hutton M. L., Dickson D. W. (2007) Neuropathologic features of frontotemporal lobar degeneration with ubiquitin-positive inclusions with progranulin gene (PGRN) mutations. J. Neuropathol. Exp. Neurol. 66, 142–151 [DOI] [PubMed] [Google Scholar]
  • 19.Mackenzie I. R., Shi J., Shaw C. L., Duplessis D., Neary D., Snowden J. S., Mann D. M. (2006) Dementia lacking distinctive histology (DLDH) revisited. Acta Neuropathol. 112, 551–559 [DOI] [PubMed] [Google Scholar]
  • 20.Lipton A. M., White C. L., 3rd, Bigio E. H. (2004) Frontotemporal lobar degeneration with motor neuron disease-type inclusions predominates in 76 cases of frontotemporal degeneration. Acta Neuropathol. 108, 379–385 [DOI] [PubMed] [Google Scholar]
  • 21.Glaser R., Kiecolt-Glaser J. K. (2005) Stress-induced immune dysfunction: implications for health. Nat. Rev. Immunol. 5, 243–251 [DOI] [PubMed] [Google Scholar]
  • 22.Raison C. L., Capuron L., Miller A. H. (2006) Cytokines sing the blues: inflammation and the pathogenesis of depression. Trends Immunol. 27, 24–31 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Murphy T. K., Sajid M. W., Goodman W. K. (2006) Immunology of obsessive-compulsive disorder. Psychiatr. Clin. North. Am. 29, 445–469 [DOI] [PubMed] [Google Scholar]
  • 24.Rao R., Sagar R., Kabra S. K., Lodha R. (2007) Psychiatric morbidity in HIV-infected children. AIDS Care 19, 828–833 [DOI] [PubMed] [Google Scholar]
  • 25.Christian L. M., Franco A., Glaser R., Iams J. D. (2009) Depressive symptoms are associated with elevated serum proinflammatory cytokines among pregnant women. Brain Behav. Immun. 23, 750–754 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Godbout J. P., Moreau M., Lestage J., Chen J., Sparkman N. L., J O. C., Castanon N., Kelley K. W., Dantzer R., Johnson R. W. (2008) Aging exacerbates depressive-like behavior in mice in response to activation of the peripheral innate immune system. Neuropsychopharmacology 33, 2341–2351 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Ryan C. L., Baranowski D. C., Chitramuthu B. P., Malik S., Li Z., Cao M., Minotti S., Durham H. D., Kay D. G., Shaw C. A., Bennett H. P., Bateman A. (2009) Progranulin is expressed within motor neurons and promotes neuronal cell survival. BMC Neurosci. 10, 130. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The FASEB Journal are provided here courtesy of The Federation of American Societies for Experimental Biology

RESOURCES