Alterations in Lysosomal, Glial and Neurodegenerative Biomarkers in Patients with Sporadic and Genetic Forms of Frontotemporal Dementia.

Background: Frontotemporal dementia (FTD) is the most common cause of early-onset dementia with 10-20% of cases caused by mutations in one of three genes: GRN, C9orf72, or MAPT. To effectively develop therapeutics for FTD, the identification and characterization of biomarkers to understand disease pathogenesis and evaluate the impact of specific therapeutic strategies on the target biology as well as the underlying disease pathology are essential. Moreover, tracking the longitudinal changes of these biomarkers throughout disease progression is crucial to discern their correlation with clinical manifestations for potential prognostic usage. Methods: We conducted a comprehensive investigation of biomarkers indicative of lysosomal biology, glial cell activation, synaptic and neuronal health in cerebrospinal fluid (CSF) and plasma from non-carrier controls, sporadic FTD (symptomatic non-carriers) and symptomatic carriers of mutations in GRN, C9orf72, or MAPT, as well as asymptomatic GRN mutation carriers. We also assessed the longitudinal changes of biomarkers in GRN mutation carriers. Furthermore, we examined biomarker levels in disease impacted brain regions including middle temporal gyrus (MTG) and superior frontal gyrus (SFG) and disease-unaffected inferior occipital gyrus (IOG) from sporadic FTD and symptomatic GRN carriers. Results: We confirmed glucosylsphingosine (GlcSph), a lysosomal biomarker regulated by progranulin, was elevated in the plasma from GRN mutation carriers, both symptomatic and asymptomatic. GlcSph and other lysosomal biomarkers such as ganglioside GM2 and globoside GB3 were increased in the disease affected SFG and MTG regions from sporadic FTD and symptomatic GRN mutation carriers, but not in the IOG, compared to the same brain regions from controls. The glial biomarkers GFAP in plasma and YKL40 in CSF were elevated in asymptomatic GRN carriers, and all symptomatic groups, except the symptomatic C9orf72 mutation group. YKL40 was also increased in SFG and MTG regions from sporadic FTD and symptomatic GRN mutation carriers. Neuronal injury and degeneration biomarkers NfL in CSF and plasma, and UCHL1 in CSF were elevated in patients with all forms of FTD. Synaptic biomarkers NPTXR, NPTX1/2, and VGF were reduced in CSF from patients with all forms of FTD, with the most pronounced reductions observed in symptomatic MAPT mutation carriers. Furthermore, we demonstrated plasma NfL was significantly positively correlated with disease severity as measured by CDR+NACC FTLD SB in genetic forms of FTD and CSF NPTXR was significantly negatively correlated with CDR+NACC FTLD SB in symptomatic GRN and MAPT mutation carriers. Conclusions: In conclusion, our comprehensive investigation replicated alterations in biofluid biomarkers indicative of lysosomal function, glial activation, synaptic and neuronal health across sporadic and genetic forms of FTD and unveiled novel insights into the dysregulation of these biomarkers within brain tissues from patients with GRN mutations. The observed correlations between biomarkers and disease severity open promising avenues for prognostic applications and for indicators of drug efficacy in clinical trials. Our data also implicated a complicated relationship between biofluid and tissue biomarker changes and future investigations should delve into the mechanistic underpinnings of these biomarkers, which will serve as a foundation for the development of targeted therapeutics for FTD.

Iduronate-2-sulfatase transport vehicle rescues behavioral and skeletal phenotypes in a mouse model of Hunter syndrome.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder caused by deficiency of the iduronate-2-sulfatase (IDS) enzyme, resulting in cellular accumulation of glycosaminoglycans (GAGs) throughout the body. Treatment of MPS II remains a considerable challenge as current enzyme replacement therapies do not adequately control many aspects of the disease, including skeletal and neurological manifestations. We developed an IDS transport vehicle (ETV:IDS) that is engineered to bind to the transferrin receptor; this design facilitates receptor-mediated transcytosis of IDS across the blood-brain barrier and improves its distribution into the brain while maintaining distribution to peripheral tissues. Here we show that chronic systemic administration of ETV:IDS in a mouse model of MPS II reduced levels of peripheral and central nervous system GAGs, microgliosis, and neurofilament light chain, a biomarker of neuronal injury. Additionally, ETV:IDS rescued auricular and skeletal abnormalities when introduced in adult MPS II mice. These effects were accompanied by improvements in several neurobehavioral domains, including motor skills, sensorimotor gating, and learning and memory. Together, these results highlight the therapeutic potential of ETV:IDS for treating peripheral and central abnormalities in MPS II. DNL310, an investigational ETV:IDS molecule, is currently in clinical trials as a potential treatment for patients with MPS II.

Rescue of a lysosomal storage disorder caused by Grn loss of function with a brain penetrant progranulin biologic.

GRN mutations cause frontotemporal dementia (GRN-FTD) due to deficiency in progranulin (PGRN), a lysosomal and secreted protein with unclear function. Here, we found that Grn-/- mice exhibit a global deficiency in bis(monoacylglycero)phosphate (BMP), an endolysosomal phospholipid we identified as a pH-dependent PGRN interactor as well as a redox-sensitive enhancer of lysosomal proteolysis and lipolysis. Grn-/- brains also showed an age-dependent, secondary storage of glucocerebrosidase substrate glucosylsphingosine. We investigated a protein replacement strategy by engineering protein transport vehicle (PTV):PGRN-a recombinant protein linking PGRN to a modified Fc domain that binds human transferrin receptor for enhanced CNS biodistribution. PTV:PGRN rescued various Grn-/- phenotypes in primary murine macrophages and human iPSC-derived microglia, including oxidative stress, lysosomal dysfunction, and endomembrane damage. Peripherally delivered PTV:PGRN corrected levels of BMP, glucosylsphingosine, and disease pathology in Grn-/- CNS, including microgliosis, lipofuscinosis, and neuronal damage. PTV:PGRN thus represents a potential biotherapeutic for GRN-FTD.

Characterization of Fluid Biomarkers Reveals Lysosome Dysfunction and Neurodegeneration in Neuronopathic MPS II Patients.

Mucopolysaccharidosis type II is a lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS) and characterized by the accumulation of the primary storage substrate, glycosaminoglycans (GAGs). Understanding central nervous system (CNS) pathophysiology in neuronopathic MPS II (nMPS II) has been hindered by the lack of CNS biomarkers. Characterization of fluid biomarkers has been largely focused on evaluating GAGs in cerebrospinal fluid (CSF) and the periphery; however, GAG levels alone do not accurately reflect the broad cellular dysfunction in the brains of MPS II patients. We utilized a preclinical mouse model of MPS II, treated with a brain penetrant form of IDS (ETV:IDS) to establish the relationship between markers of primary storage and downstream pathway biomarkers in the brain and CSF. We extended the characterization of pathway and neurodegeneration biomarkers to nMPS II patient samples. In addition to the accumulation of CSF GAGs, nMPS II patients show elevated levels of lysosomal lipids, neurofilament light chain, and other biomarkers of neuronal damage and degeneration. Furthermore, we find that these biomarkers of downstream pathology are tightly correlated with heparan sulfate. Exploration of the responsiveness of not only CSF GAGs but also pathway and disease-relevant biomarkers during drug development will be crucial for monitoring disease progression, and the development of effective therapies for nMPS II.

Alterations in cancer stem-cell marker CD44 expression predict oncologic outcome in soft-tissue sarcomas.

BACKGROUND: Cancer stem cells (CSCs) have been shown to resist chemotherapy and promote metastasis after cytotoxic therapies. We sought to determine if the expression of CSC markers (aldehyde dehydrogenase [ALDH], CD44, and epidermal growth factor receptor [EGFR]) predicted outcomes in soft-tissue sarcoma (STS) patients. METHODS: We queried an institutional database of 23 STS patients and evaluated immunohistochemical expression of CSC markers ALDH, CD44, and EGFR. The Cancer Genome Atlas (TCGA) was also queried for STS clinical and genomic data. Disease-specific (DSS) and overall survival (OS) were assessed by univariate and Kaplan-Meier analysis. RESULTS: Of the 23 institutional patients, the majority was female, had high-grade tumors and had extremity tumors. With a median follow-up of 27 months, nine patients (39%) experienced distant recurrence, and four (17%) died of disease. Mean H-scores at diagnosis (±standard error of the mean) for CD44, ALDH1, and EGFR were 169 ± 27, 77 ± 15, and 144 ± 23, respectively. On univariate analysis, there was a trend for increased CD44 score to predict both worse DSS and OS (hazard ratio = 1.01, 95% confidence interval 1-1.02, P = 0.056), whereas ALDH and EGFR scores did not. Analysis of 74 TCGA STS cases with complete clinical and genomic data revealed that CD44 copy number alterations predicted worse DSS (9.89 months versus 72.5 months, P = 0.007) and a trend for worse OS (14.03 months versus 38.6 months, P = 0.12), whereas ALDH1 and EGFR copy number alteration did not. Multivariate analysis of the combined data sets was consistent with worse DSS among patients with higher CD44 expression. CONCLUSIONS: Institutional and national TCGA data show the association of elevated baseline CD44 expression with worse STS outcomes. Further study of CD44 as a possible novel STS biomarker appears indicated.

Increasing Rates of No Treatment in Advanced-Stage Non-Small Cell Lung Cancer Patients: A Propensity-Matched Analysis.

INTRODUCTION: Variation in treatment and survival outcomes for NSCLC is high among patients with stage III or IV disease, but patients with untreated NSCLC have not been critically analyzed to evaluate for improvable outcomes. We evaluated treatment trends and their association with oncologic outcomes for NSCLC, hypothesizing that there are a substantial number of untreated patients who are similar to patients who undergo treatment. METHODS: Linear regression was used to calculate trends in utilization of treatment. Kaplan-Meier and Cox regression modeling were used to determine predictors of receiving treatment. Propensity matching was used to compare survival among subsets of treated versus untreated patients. RESULTS: Patients with primary NSCLC were identified from the National Cancer Data base from 1998 to 2012, and 21% of patients (190,539) received no treatment. For stage IIIA and IV, the proportion of untreated patients increased over the study period by 0.21% and 0.4%, respectively (p = 0.003 and p < 0.0001). Regardless of stage, untreated patients had significantly shorter overall survival (OS) (p < 0.0001). Propensity-matched analyses of 6144 stage IIIA patient pairs treated with chemoradiation versus no treatment confirmed shorter OS for untreated patients (median 16.5 versus 6.1 months, p < 0.0001). For 19,046 stage IV patient pairs treated with chemotherapy versus no treatment, similar results were obtained (median OS 9.3 versus 2.0 months, p < 0.0001). CONCLUSIONS: The proportion of untreated patients with stage IIIA and IV disease is increasing. Survival outcomes among patients with advanced-stage disease are superior with treatment, independent of selection bias. The benefits and risks of treatment should be carefully assessed before choosing to forego treatment.