Progranulin Levels Research Articles

Anti-sortilin1 Antibody Up-Regulates Progranulin via Sortilin1 Down-Regulation.

Progranulin (PGRN) haploinsufficiency associated with loss-of-function mutations in the granulin gene causes frontotemporal dementia (FTD). This suggests that increasing PGRN levels could have promising therapeutic implications for patients carrying GRN mutations. In this study, we explored the therapeutic potential of sortilin1 (SORT1), a clearance receptor of PGRN, by generating and characterizing monoclonal antibodies against SORT1. Anti-SORT1 monoclonal antibodies were generated by immunizing Sort1 knockout mice with SORT1 protein. The antibodies were classified into 7 epitope bins based on their competitive binding to the SORT1 protein and further defined by epitope bin-dependent characteristics, including SORT1-PGRN blocking, SORT1 down-regulation, and binding to human and mouse SORT1. We identified a positive correlation between PGRN up-regulation and SORT1 down-regulation. Furthermore, we also characterized K1-67 antibody via SORT1 down-regulation and binding to mouse SORT1 in vivo and confirmed that K1-67 significantly up-regulated PGRN levels in plasma and brain interstitial fluid of mice. These data indicate that SORT1 down-regulation is a key mechanism in increasing PGRN levels via anti-SORT1 antibodies and suggest that SORT1 is a potential target to correct PGRN reduction, such as that in patients with FTD caused by GRN mutation.

AL001 restores CSF PGRN levels and normalizes disease‐associated biomarkers in individuals with frontotemporal dementia due to heterozygous mutations in the progranulin gene

AbstractBackgroundAL001 is a recombinant humanized anti‐Sortilin monoclonal antibody in development for frontotemporal dementia (FTD). Mutations in a single copy of the progranulin gene (GRN) leads to a 50% or greater decrease in the level of circulating progranulin (PGRN) protein levels and are causative of FTD. The disease is associated with increased inflammation and impaired lysosomal function in the brain. The INFRONT Phase 1/1b clinical study AL001‐1 investigated the safety, tolerability, pharmacokinetics and pharmacodynamics of intravenously administered AL001 in healthy volunteers (HV) and participants with a GRN mutation causative of FTD (FTD‐GRN). In addition, the study investigated the effect of AL001 on disease‐associated biomarkers.MethodA total of 64 participants were enrolled in the AL001‐1 study. In the single dose ascending part of the study, 50 healthy volunteer participants were enrolled with 38 exposed to AL001 and 12 exposed to placebo. The study enrolled 6 asymptomatic FTD‐GRN and 8 symptomatic FTD‐GRN participants. The 8 symptomatic FTD‐GRN participants received 3 doses of 30 mg/kg of AL001 over 4 weeks.ResultTreatment of symptomatic FTD‐GRN participants with AL001 over 4 weeks restored PGRN levels in the cerebrospinal fluid (CSF) to normal levels for more than 8 weeks. To further investigate the effects of restoring PGRN levels, partial normalization of a FTD disease proteomic signature was observed in the CSF 4 weeks after the last dose in multidose treatment group. Compared to healthy volunteers, AL001 treatment rescued cathepsin B (CTSB), a marker of lysosomal function, by 58%. AL001 treatment also partially normalized markers of inflammation and gliosis, osteopontin (SPP1) and chitotriosidase (CHIT1) by 52% and 22%, respectively. In addition to the reversal of these disease phenotypes, a 14% reduction (n.s.) in plasma neurofilament light chain (NfL), a marker of neuron injury and stress, was observed after 8 weeks after the last dose.ConclusionAL001 treatment resulted in a sustained increase in plasma and CSF PGRN in FTD‐GRN mutation carriers. New data showed reduction of NfL and normalization of proteins associated with the disease after one month of dosing. These results have supported progressing AL001 to Phase 2 and pivotal Phase 3 studies.

Loss of progranulin leads to dysregulation of innate and adaptive immune cell populations, increased susceptibility to experimental colitis, and brain infiltration of peripheral immune cells

AbstractBackgroundMutations in the progranulin gene (GRN) reduce levels of progranulin (PGRN) and granulins (GRNs) causing frontotemporal dementia (FTD), the most common form of early‐onset dementia. PGRN loss in neurons is associated with lysosome dysfunction resulting in diminished cathepsin protease activity. PGRN is also highly expressed in brain‐resident microglia and peripheral immune cells. Therefore, we asked if PGRN loss impacts immune cell profiles and communication in the gut‐brain axis during chronic systemic inflammation.MethodsWe measured lysosomal‐associated proteases in microglia and peripheral immune cells using probes for cathepsin D and pan‐cysteine cathepsins; performed multiplexed RNA & digital spatial protein profiling analyses, immunohistochemistry, and deep‐immunophenotyping by flow cytometry on brain, spleen, and peripheral blood of Grn KO and Grn‐suffficient mice aged 3‐30 months. Furthermore, we exposed mice to experimental colitis to interrogate alterations in the gut‐brain axis.ResultsHighest cathepsin D activity was found amongst Ly6C+, CD11b+ blood monocytes while pan‐cathepsin activity was highest in neutrophils and monocytes. In the spleen of aged Grn KO mice, T cell counts were reduced while Ly6C‐, CD68+ macrophages were increased compared to age‐matched Grn‐sufficient mice. In blood, aberrant T cell and monocyte activation markers in Grn KO mice were evident with minimal increases in inflammatory cytokines in plasma. Aged Grn KO mice exhibited decreased microglia (CD45int, CD11bhi) in the brain relative to Grn‐sufficient mice, with altered MHCII and CD68 expression. Additionally, CD4+ and CD8+ T cells were impacted in the brain of Grn KO mice compared to age‐matched Grn‐sufficient mice. PGRN loss was also associated with increased brain infiltration of activated peripheral monocytes and, interestingly, increased vulnerability to experimental colitis that was mitigated by loss of CCR2 function.ConclusionsThese novel findings suggest that PGRN plays key regulatory functions in innate and adaptive immune cell populations, in central‐peripheral immune cell crosstalk and traffic to the CNS, and in regulating susceptibility to immune challenges that disrupt the gut‐brain signaling axis. Analysis of peripheral immune cells and colonic tissue from patients with Grn mutations or SNPs is ongoing and may shed light on the mechanisms by which GRN haploinsufficiency causes FTD.

A brain penetrant progranulin biotherapeutic rescues lysosomal and inflammatory phenotypes in the brain of GRN knockout mice

AbstractBackgroundHeterozygous loss of function (LOF) mutations in GRN cause frontotemporal dementia (FTD), a neurodegenerative disorder associated with lysosomal dysfunction, TDP‐43 pathology and inflammation in the CNS. Additionally, homozygous LOF mutations cause neuronal ceroid lipofuscinosis, a lysosomal storage disorder. GRN encodes progranulin (PGRN), a soluble protein that is most abundantly expressed in microglia, where it localizes to lysosomes and can undergo secretion. Although the precise function of PGRN is unknown, growing evidence suggests that it regulates lysosomal function, inflammatory responses and promotes neuronal survival. Accordingly, PGRN LOF models are associated with lysosomal defects, hyperinflammatory responses, and decreased neuronal viability, both in vitro and in vivo. Because GRN‐FTD patients exhibit reduced levels of PGRN in biofluids and tissues, including the brain, a protein replacement therapy analogous to enzyme replacement therapy and capable of crossing the blood brain barrier (BBB) more efficiently may represent a powerful approach to slow or prevent disease progression.MethodHere we describe a novel therapeutic for increasing brain penetrance of PGRN, referred to as Protein Transport Vehicle (PTV):PGRN. PTV:PGRN consists of recombinant human PGRN fused to a modified Fc domain engineered to bind to the human transferrin receptor (huTfR), thus facilitating receptor‐mediated transcytosis across the BBB.ResultWe found that extracellular applications of PTV:PGRN rescue a range of Grn KO cell phenotypes in vitro, including lysosomal proteolysis and alteration in the levels of bis(monoacylglycero)phosphate (BMP), an endolysosomal phospholipid involved in lysosomal lipid catabolism. Intravenously administered PTV:PGRN showed increased acute brain exposure in huTfR knock‐in (TfRmu/hu) mice relative to a regular Fc:PGRN fusion that does not bind to huTfR. Importantly, low doses of PTV:PGRN, but not Fc:PGRN, fully corrected lysosomal lipid alterations, including BMP deficiency, as well as inflammatory markers in the brain of Grn KO x TfRmu/hu mice.ConclusionOur data suggest that PTV:PGRN may represent a viable therapeutic strategy for the treatment of GRN‐FTD and potentially other disorders associated with PGRN deficiency.

Changes in serum progranulin level and inflammatory markers in diabetic neuropathy

Changes in serum progranulin level and inflammatory markers in diabetic neuropathy

Haploinsufficiency of progranulin causes impairments in PINK/PARKIN mitophagy

AbstractBackgroundGRN mutations, resulting in haploinsufficiency of progranulin, cause frontotemporal dementia (FTD) with TDP‐43 pathology. Impairments in mitophagy, the selective autophagy of damaged mitochondria, have been identified in several neurodegenerative diseases, and multiple neurodegenerative disease genes, including PINK1, Parkin, VCP and TBK1, have been shown to play a role in this pathway. A role for progranulin in the regulation of neuronal mitophagy has not been explored, however progranulin deficient mice exhibit reduced xenophagy (selective clearance of bacteria). We therefore hypothesised that loss of progranulin could lead to defective mitophagy.MethodWe used two in vitro models to investigate PINK1/Parkin mitophagy: SHSY5Y cells overexpressing Parkin (PoE‐SHSY5Y) +/‐ siRNA against GRN, and induced pluripotent stem cell (iPSC) derived cortical neurons from two patients with FTD‐associated GRN mutations (R493X and C31fs). PINK1/Parkin mitophagy was induced using a combination of Antimycin A (respiratory complex III inhibitor) and oligomycin (ATP synthase inhibitor), and PINK1 accumulation and levels of S65 phosphorylated ubiquitin (the substrate of PINK1 and a marker of its activity) were examined using western blot and immunofluorescence. Subsequent mitophagy was assessed by examining Mitofusin‐2 ubiquitination and degradation, and TIM23 levels by western blot.ResultA reduction in progranulin levels resulted in reduced accumulation of PINK1 and lower levels of mitochondrial phospho‐ubiquitin following oligomycin/antimycin treatment in both PoE‐SHSY5Y and iPSC‐neurons with GRN mutations. Ubiquitination and degradation of mitofusin‐2 was also decreased in cells with reduced progranulin.ConclusionThese results suggest that progranulin plays a role in mitophagy by regulating stability and/or activity of PINK1. Ongoing work aims to understand the mechanisms by which progranulin and/or individual granulins contribute to this process and to dissect cell‐type specific contributions of progranulin to mitophagy in iPSC‐ derived neurons, astrocytes and microglia.

An ABCA7 partial deletion and a GRN variant in a semantic variant of primary progressive aphasia patient

AbstractBackground ABCA7 gene (ATP‐binding cassette transporter A7) loss‐of‐function mutations are related to increased risk of suffering Alzheimer’s disease (AD). On the other hand, mutations in GRN (Progranulin) gene are causative of frontotemporal dementia (FTD).MethodsThe proband was a patient diagnosed from semantic variant of primary progressive aphasia. Age at onset was at 50 years‐old, presenting progressive cognitive decline with an important language loss. The MRI showed a left temporal atrophy. AD CSF biomarkers were normal and no familial history of dementia was reported. Next generation sequencing was performed with Illumina NextSeq500. Single nucleotide variants were detected using GATK and copy number variants using ExomeDepth algorithm. Sanger sequencing was performed for GRN variant confirmation and MLPA technique for ABCA7 deletion validation. C9orf72 repeat expansion was studied with a repeat primed PCR and fragment analysis. Biological samples from his mother and a brother were obtained. Commercial ELISA kit was used to measure serum PGRN levels (Adipogen).ResultsPatient showed an ABCA7 partial deletion (exons 17‐47) plus 4 contiguous genes, of a total of 105 kb in size (hg19 chr19:g.1048865_1154298). Deletion was confirmed in the proband and discarded in the proband’s mother and brother by MLPA. Patient and his mother (asymptomatic at 81 yo) were also carriers of a reported GRN variant, p.(Asp33Glu; rs63750742). Progranulin serum levels were normal in the patient and his family members. C9orf72 screening was negative.ConclusionsThe patient harbored two genetic alterations in genes related to dementia risk, although it is unlikely that any of them alone could be responsible of the FTD phenotype. ABCA7 deletion should be de novo or father inherited. ABCA7 protein truncating variant at exon 14 (p.Arg578fs), which has a similar protein consequence, is relatively frequent in control population, although has showed a 1.8‐fold enrichment in AD patients. Moreover, GRN variant does not seem to be pathogenic or low penetrance because proband’s mother is unaffected and serum progranulin levels are normal. In conclusion, these variants per se are likely not sufficient to cause the disease, but rather risk variants of intermediate to high penetrance along with other factors.

Alpha-lipoic acid treatment increases serum progranulin level in diabetic neuropathy

Alpha-lipoic acid treatment increases serum progranulin level in diabetic neuropathy

Serum progranulin level is associated with disease activity following orthopedic surgery in rheumatoid arthritis patients.

BackgroundFew studies have focused on the ability of progranulin to predict postoperative disease activity in rheumatoid arthritis (RA) patients who have undergone surgery. This study evaluated serum progranulin levels in active RA patients and analyzed its relationship with postoperative disease activity.MethodsOne hundred thirty-two patients with active RA and 72 healthy subjects were included in this study. Serum progranulin was measured, and clinical data were collected. The postoperative 1-year Disease Activity Score in 28 joints calculated with C-reactive protein (DAS28-CRP) scores was evaluated as an indicator of disease activity. The predictive value of progranulin in postoperative 1-year disease activity in RA patients was also analyzed.ResultsSerum progranulin was significantly associated with the postoperative 1-year RA disease activity. The mean serum progranulin level in patients with a high disease activity was significantly higher than that of RA patients with low-to-moderate disease activity (54.2 ± 10.6 ng/mL vs. 46.7 ± 8.8 ng/mL). Serum progranulin was also evaluated as an independent predictive factor for postoperative 1-year RA disease activity in multivariate analysis (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.02–8.85).ConclusionsSerum progranulin levels may be a promising indicator of postoperative disease activity in RA patients who underwent orthopedic surgery.

Progranulin Promotes Osteogenic Differentiation and Osteosynthesis of Bone Marrow Mesenchymal Stem Cells and Alleviates Osteoporosis Through Phosphatidylinositol 3-Kinase/Protein Kinase B/Peroxisome Proliferator-Activated Receptor γ Pathway

Bone marrow mesenchymal stem cells (BMSCs) have self-renewal potential with multi-directional differentiation. Progranulin prevents bone degradation, inhibits inflammation and protects bone tissue. However, the role of Progranulin in osteoporotic BMSCs is unclear. Osteoporosis (OP) rat models were prepared by ovarian removal and treated with different doses (5 and 10 μM) of Progranulin followed by analysis of BMP-2 level by ELISA, bone mineral density and ALP activity. OP rat BMSCs were isolated and assigned into control group and Progranulin group followed by analysis of Progranulin level by ELISA, cell proliferation by MTT assay, RUNX2 and COL1A1 mRNA level by Real time PCR, and PI3K/Akt/PPARγ signaling protein level by Western blot. Progranulin treatment of OP rats dose-dependently increased BMP-2 expression, bone density and ALP activity. Compared with OP group, there were significant differences (P <0.05). Progranulin expression and BMSCs proliferation was increased, and RUNX2 and COL1A1 mRNA expression was elevated in Progranulin-treated OP group along with increased PI3K/Akt expression and decreased PPARγ protein expression. Compared with OP group, the difference was statistically significant, and the change was more significant with increasing concentration (P <0.05). Progranulin promotes BMSCs osteogenic differentiation and proliferation by regulating PI3K/Akt/PPARγ signaling pathway, which is beneficial for OP rats’ bone synthesis.

Cross-Sectional and Longitudinal Associations Between Plasma Neurodegenerative Biomarkers and Physical Performance Among Community-Dwelling Older Adults

Abstract Background Plasma amyloid-beta (Aβ), neurofilament light chain (NfL), and progranulin (PGRN) have been related to multiple neurodegenerative conditions that might affect physical performance. The aim of this study was to explore the relationship between these plasma neurodegenerative markers and physical performance among community-dwelling older adults. Methods Five hundred and seven older adults (aged 76 ± 5 years) previously recruited in the Multidomain Alzheimer’s Preventive Trial, and had received blood and physical performance tests, were included in this study. Plasma Aβ (Aβ 42/Aβ 40 ratio), NfL, and PGRN levels were measured. Physical performance was assessed by handgrip strength and the Short Physical Performance Battery (combining gait speed, chair stands, and balance tests). Physical performance measured at the same time point and after the blood tests were used. Mixed-effect linear models were performed with age, sex, allocation to Multidomain Alzheimer’s Preventive Trial group, body mass index, and Mini-Mental State Examination score as covariates. Results The mean values of Aβ 42/Aβ 40 ratio, NfL, and PGRN were 0.11, 84.06 pg/mL, and 45.43 ng/mL, respectively. At the cross-sectional level, higher plasma NfL was associated with a lower Short Physical Performance Battery score (β = −0.004, 95% CI [−0.007, −0.001]). At the longitudinal level, higher PGRN levels were associated with decreasing handgrip strength over time (β = −0.02, 95% CI [−0.04, −0.007]). All the other associations were statistically nonsignificant. Conclusion Our findings suggest the possibility of using plasma NfL and PGRN as markers of physical performance in older adults.

Secretory leukocyte protease inhibitor and progranulin as possible regulators of cervical remodeling in pregnancy

Secretory leukocyte protease inhibitor (SLPI) and progranulin (PGRN) are secretory proteins with an anti-inflammatory property. Their involvement in cervical remodeling in pregnant uterus is not yet elucidated. Thus, this study aimed to explore the significance of SLPI and PGRN in the maintenance of pregnancy by investigating the factors associated with their expression levels at the cervix. Concentrations of SLPI and PGRN proteins were measured in cervical mucus samples collected from asymptomatic pregnant women at 24–26 weeks of gestation (n = 166). The concentrations of those molecules were analyzed with clinical parameters related to risk for preterm delivery (PD). In pregnant mice, we evaluated the effect of lipopolysaccharide-induced inflammation and progesterone effect modulation on cervical mRNA expression of SLPI and PGRN. The cervical PGRN level was significantly lower in women with short cervix (<35 mm) and with a history of threatened PD. In women with short cervix, cervical SLPI concentrations were positively correlated with inflammatory cytokines, interleukin-6 (R2 = 0.75) and interleukin-8 (R2 = 0.71). In pregnant mice, cervical mRNA expressions of PGRN and SLPI were increased in response to progesterone supplementation and were suppressed by a progesterone antagonist, mifepristone. Lipopolysaccharide-induced inflammation caused remarkable upregulation in cervical SLPI mRNA level but not in PGRN. Progesterone and local inflammation are the factors controlling expression levels of PGRN and SLPI at the cervix. The observed relationship of PGRN and SLPI levels in the cervical mucus with PD-related clinical parameters supports that those anti-inflammatory molecules possibly play a significant role in appropriate regulation of cervical remodeling.

STUDY OF SERUM PROGRANULIN LEVEL AND ITS RELATION TO MICROVASCULAR COMPLICATIONS IN PATIENTS WITH TYPE 1 DIABETES

Progranulin (PGRN) is a cysteine rich secreted protein, expressed in epithelial cells, immune cells, neurons, and adipocytes. Full length PGRN stimulates cell growth and survival and has anti-inflammatory activity. However, proteolytic cleavage of PGRN producesgranulin peptides (GRNs), some of which stimulate inflammation. Recent studies have demonstrated that activation of inflammatory process may lead to development of diabetic microangiopathy.Aim of the workThe aim of the present study was to study the relation between serum Progranulin level and microvascular complications in subjects with type 1 diabetes mellitus.Subjects and methodsThis study included 80 subjects classified as: 20 healthy subjects as a control group, 20 diabetic patients with duration of DM less than one year and 40 diabetic patients with duration more than 5 years. Serum progranulin level was measured by ELISA technique. This study included 80 subjects classified as: 20 healthy subjects as a control group, 20 diabetic patients with duration of DM less than one year and 40 diabetic patients with duration more than 5 years. Serum progranulin level was measured by ELISA technique.

Regulation of progranulin expression and location by sortilin in oxygen–glucose deprivation/reoxygenation injury

Progranulin is a secreted glycoprotein expressed in neurons and microglial cells that is involved in maintaining physiological functions. Many studies have found that progranulin may play a protective role against ischemic brain injury, but little is known about how the expression level and cellular localization status of progranulin is regulated after hypoxia–ischemia. Research has confirmed that sortilin, encoded by SORT1, can bind with progranulin and deliver a mature secretory isoform of progranulin to lysosomes, and progranulin is then cleaved. In the present study, we aimed to figure out whether sortilin could affect the expression and cellular localization of progranulin and regulate cell apoptosis during hypoxia–ischemia. In this study, oxygen–glucose deprivation/reoxygenation (OGD/R) in primary cortical neurons was used to mimic hypoxic–ischemic episodes. After OGD/R, the neuroprotective effects of progranulin against hypoxia–ischemia were examined, and primary cortical neurons were transduced with a SORT1 knockdown lentivirus to inhibit the expression of sortilin. The results showed that sortilin inhibition increased PGRN expression and alleviated cell injury induced by hypoxia–ischemia. Additionally, sortilin inhibition was associated with less PGRN localization in lysosomes. All of these findings suggest that sortilin can regulate the expression of PGRN, most likely by transporting it to lysosomes and affecting the cell injury in hypoxia–ischemia.

Adeno-associated virus serotype 1-based gene therapy for FTD caused by GRN mutations.

ObjectiveDominant loss‐of‐function mutations in the gene encoding the lysosomal protein, progranulin, cause 5‐10% of frontotemporal dementia cases. As progranulin undergoes secretion and endocytosis, a small number of progranulin‐expressing cells can potentially supply the protein to the entire central nervous system. Thus, gene therapy is a promising treatment approach.MethodsWe evaluated adeno‐associated viral vector administration into the cerebrospinal fluid as a minimally invasive approach to deliver the granulin gene to the central nervous system in a murine disease model and nonhuman primates.ResultsIn progranulin‐deficient mice, vector delivery into the lateral cerebral ventricles increased progranulin levels in the cerebrospinal fluid and normalized histological and biochemical markers of progranulin deficiency. A single vector injection into the cisterna magna of nonhuman primates achieved CSF progranulin concentrations up to 40‐fold higher than those of normal human subjects and exceeded CSF progranulin levels of successfully treated mice. Animals treated with an adeno‐associated virus serotype 1 vector exhibited progranulin expression fivefold higher than those treated with an AAV5 vector or the AAV9 variant, AAVhu68, apparently due to remarkably efficient transduction of ependymal cells. Progranulin expression mediated by adeno‐associated viral vectors was well tolerated in nonhuman primates with no evidence of dose‐limiting toxicity, even at vector doses that induced supraphysiologic progranulin expression.InterpretationThese findings support the development of AAV1‐based gene therapy for frontotemporal dementia caused by progranulin deficiency.

Serum progranulin levels are associated with frailty in middle-aged individuals.

Background and objectiveA recent study identified progranulin as a candidate biomarker for frailty, based on gene expression databases. In the present study, we investigated associations between serum progranulin levels and frailty in a population-based sample of late middle-age and older adults.MethodsWe utilized a cohort study that included 358 African Americans (baseline ages 49–65). Frailty was assessed by three established methods: the interview-based FRAIL scale, the Cardiovascular Health Study (CHS) frailty scale that includes performance-based measurements, and the Frailty Index (FI) that is based on cumulative deficits. Serum levels of the following proteins and metabolites were measured: progranulin, cystatin C, fructosamine, soluble cytokine receptors (interleukin-2 and -6, tumor necrosis factor α-1 and -2), and C-reactive protein. Sarcopenia was assessed using the SARC-F index. Vital status was determined by matching through the National Death Index (NDI).ResultsSerum progranulin levels were associated with frailty for all indices (FRAIL, CHS, and FI) but not with sarcopenia. Inflammatory markers indicated by soluble cytokine receptors (sIL-2R, sIL-6R, sTNFR1, sTNFR2) were positively associated serum progranulin. Increased serum progranulin levels at baseline predicted poorer outcomes including future frailty as measured by the FRAIL scale and 15-year all-cause mortality independent of age, gender, and frailty.ConclusionsOur findings suggest that serum progranulin levels may be a candidate biomarker for physical frailty, independent of sarcopenia. Further studies are needed to validate this association and assess the utility of serum progranulin levels as a potential biomarker for prevalent frailty, for risk for developing incident frailty, and for mortality risk over and above the effect of baseline frailty.

Progranulin modulates cartilage-specific gene expression via sirtuin 1–mediated deacetylation of the transcription factors SOX9 and P65

Progranulin (PGRN) is an autocrine growth factor that exerts crucial roles within cartilage tissue; however, the molecular mechanisms underlying PGRN-mediated cartilage homeostasis remain elusive. In the present study, we investigated the role of PGRN in regulating chondrocyte homeostasis and its therapeutic potential for managing osteoarthritis (OA). We found that PGRN levels are significantly increased in human cartilage in mild OA and that its expression is decreased in the cartilage in severe OA. In vitro, treatment of primary rat chondrocytes with recombinant PGRN significantly enhanced the levels of collagen type II α 1 chain (COL2A1) and aggrecan, and attenuated TNFα-induced up-regulation of matrix metallopeptidase 13 (MMP13) and ADAM metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS5) in chondrocytes. These effects were abrogated in SIRT1-/- cells, indicating a causative role of SIRT1 in the effects of PGRN on protein expression in chondrocytes. Mechanistically, PGRN increased SIRT1 expression and activity, which reduced the acetylation levels of SRY-box transcription factor (SOX9) and transcription factor P65 (P65) and thereby promoted nuclear translocation of SOX9 and inhibited TNFα-induced P65 nuclear accumulation to maintain chondrocyte homeostasis. In conclusion, our findings reveal a mechanism of action for PGRN that maintains cartilage homeostasis and supports the notion that PGRN up-regulation may be a promising strategy for managing OA.

Abstract 1145: Assessing the diagnostic value of the combination of Matrix Metalloproteinase 2 (MMP2) and Progranulin (PGRN) preoperative plasma levels for colorectal cancer (CRC)

Abstract Introduction: MMP 2, also known as Gelatinase A, is an extracellular matrix remodeling enzymes. MMP-2 activity is regulated by various oncogenes, cytokines and growth factors. MMP 2 functions in the breakdown of extracellular matrix (ECM) and participates in tumor neoangiogensis. It is also associated with an angiogenic and metastatic tumor cell phenotype, in vivo. Up-regulation of MMP-2 aggravates the loss of basement membrane type IV collagen, breaks down ECM and promotes tumor progression and invasion. Progranulin (PGRN) is a ubiquitously expressed secreted glycoprotein that activates both the PI3k and ERK pathways, and promotes cyclin D1 and cyclin B expression which supports proliferation and survival of mesenchymal and epithelial origin cells. PGRN stimulates VEGF expression in breast cancer cells, in vitro, and stimulates inflammation, fibroblast accumulation and angiogenesis. Over-expression of MMP2 and PGRN has been reported in many cancers including CRC. The aim of this study was to compare preoperative (preop) plasma MMP2 and PGRN levels in CRC and benign colonic disease (BCD) patients (pts), alone and in combination, as a means of detecting CRC. Method: Preop plasma samples were obtained from consenting CRC and BCD pts undergoing elective resection for whom adequate preop plasma was available from an IRB approved tissue bank. Demographic, clinical, and pathologic data were collected. PreOp plasma levels of MMP2 and PGRN (ng/ml) were determined via ELISA in duplicate and reported as median + 95%CI. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to assess single or multiple plasma protein levels as a diagnostic tool for CRC. The Mann-Whitney test was used for statistical analysis (significance p&amp;lt;0.05). Results: A total of 172 CRC pts (70% colon, 30% rectal) and 102 BCD pts (adenoma 33%, diverticulitis 54%, other 15%) were eligible for the study. The CRC pathologic stage distributions were: Stage-I, 25%; Stage-2, 32%, Stage-3, 31%, Stage- 4, 12%. Median preop plasma protein levels in CRC pts were significantly higher than BCD pts. [MMP2; 205.3,CI 198.2,217.5 vs.165.3,CI 156.8,179.1: PGRN; 54.7,CI 51.8,57.1 vs.43.3,CI 40.1,46.8,P&amp;lt;0.001) The AUC value for ROC curve for MMP2 and PGRN were 0.721 and 0.724 respectively with 73% and 71% specificity. AUC for the combination of these 2 proteins was 0.757 with 97% specificity. Conclusion: Median MMP2 and PGRN levels were higher in CRC pts and the CRC median values were 24% and 26% higher than BCD median levels respectively. ROC curve analysis showed that the two protein combination improved specificity and AUC values. MMP2 and PGRN are potential candidates for a larger diagnostic panel to include other proteins found to be elevated in CRC pts. Further study is warranted. Citation Format: Chandana S K Herath Mudiyanselage, Neil Mitra, Dasuni Niyagama Gamage, Hiromichi Miyagaki, Abhinit Shah, Xiaohong Yan, Vesna Cekic, Richard L. Whelan. Assessing the diagnostic value of the combination of Matrix Metalloproteinase 2 (MMP2) and Progranulin (PGRN) preoperative plasma levels for colorectal cancer (CRC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1145.

Discovery of small molecules that normalize the transcriptome and enhance cysteine cathepsin activity in progranulin-deficient microglia

Patients with frontotemporal dementia (FTD) resulting from granulin (GRN) haploinsufficiency have reduced levels of progranulin and exhibit dysregulation in inflammatory and lysosomal networks. Microglia produce high levels of progranulin, and reduction of progranulin in microglia alone is sufficient to recapitulate inflammation, lysosomal dysfunction, and hyperproliferation in a cell-autonomous manner. Therefore, targeting microglial dysfunction caused by progranulin insufficiency represents a potential therapeutic strategy to manage neurodegeneration in FTD. Limitations of current progranulin-enhancing strategies necessitate the discovery of new targets. To identify compounds that can reverse microglial defects in Grn-deficient mouse microglia, we performed a compound screen coupled with high throughput sequencing to assess key transcriptional changes in inflammatory and lysosomal pathways. Positive hits from this initial screen were then further narrowed down based on their ability to rescue cathepsin activity, a critical biochemical readout of lysosomal capacity. The screen identified nor-binaltorphimine dihydrochloride (nor-BNI) and dibutyryl-cAMP, sodium salt (DB-cAMP) as two phenotypic modulators of progranulin deficiency. In addition, nor-BNI and DB-cAMP also rescued cell cycle abnormalities in progranulin-deficient cells. These data highlight the potential of a transcription-based platform for drug screening, and advance two novel lead compounds for FTD.

Assessment the Serum progranulin level as a biomarker for retinopathy in type 2 diabetic patients

Background: Micro vascular complications of T2DM are associated with severe morbidity, mortality and a huge economic burden. So, there is an important need to identify new biomarker able to identify disease onset and progression and can be used as a therapeutic target for management of these complications. The Aim of this study was to assessment the Serum progranulin level as a biomarker for the presence and severity of retinopathy in type 2 diabetic patients. Patients and Methods: The current case-control study was carried out conducted on (48 type 2 diabetic patients) at the Internal Medicine and ophthalmology out-patient clinic of Zagazig University Hospitals, during the period from May 2019 to October 2019. All patient referred to ophthalmic out-patient clinic for fundal examination by ophthalmologist ,in which diabetic retinopathy was diagnosed, a complete physical examination including the measurement of height, weight, body mass index, and blood pressure (BP) was performed for all patients. Results: The current study showed that there was a high statistical significant increase in serum PGRN level in diabetic patients with retinopathy, there was a statistical significant positive correlation between serum PGRN level with disease duration, urea, creatinine level and urinary ACR of studied retinopathy patients and also there was a high statistical significant increase in serum PGRN level in diabetic patients with proliferative retinopathy. Conclusions: According to our results serum PRGN level could be used as a biomarker for the presence of microvascular retinal complication and to anticipate the severity of diabetic retinopathy in T2DM patients