Expression and Function of Histone Deacetylase 10 (HDAC10) in B Cell Malignancies

Histone deacetylase 10 (HDAC10) belongs to the class IIb HDAC family and its biological role remains mostly unidentified. A decreased HDAC10 expression has been reported in patients with aggressive solid tumors (Osada et al. Int J Cancer 112: 26-32, 2004; Jin et al. Int J Clin Exp Pathol 7: 5872-5879, 2014), suggesting that loss of HDAC10 expression might confer a survival advantage to malignant cells. Consequently, results from our lab suggests that overexpression of HDAC10 in aggressive mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) Z138c and MEC1 cells, respectively, resulted in a rapid induction of cell death in vitro with only 5 % of cells being alive at 48 h, cell cycle arrest, and up-regulation of co-stimulatory molecules. Here we present several standard methods to study the function of HDAC10 in B cell malignancies.

WT1 vaccination in AML and MDS: A pilot trial with synthetic analog peptides

Peptide vaccines are capable of eliciting immune responses targeting tumor-associated antigens such as the Wilms' Tumor 1 (WT1) antigen, often overexpressed in myeloid malignancies. Here, we assessed the safety, tolerability, and immunogenicity of a polyvalent WT1 peptide vaccine. Individuals with WT1-positive acute myeloid leukemia (AML) in first (CR1) or second (CR2) remission or with higher-risk myelodysplastic syndrome (MDS) following at least 1 prior line of therapy were vaccinated with a mixture of peptides derived from the WT1 protein, with sargramostim injections before vaccination to amplify immunogenicity. Six vaccinations were delivered biweekly, continuing then monthly until patients received 12 vaccinations or showed disease relapse or progression. Therapeutic efficacy was evaluated by progression-free and overall survival. Immune responses were evaluated by delayed-type hypersensitivity testing and T-cell IFNγ ELISPOT at specified intervals. In 16 patients who received at least one vaccination, 10 completed the planned course of six vaccinations and six continued for up to six additional monthly vaccinations. Vaccinations were well tolerated, with no patients discontinuing due to toxicity. One of two patients with high-risk MDS experienced a prolonged decrease in transfusion dependence. Two of 14 AML patients demonstrated relapse-free survival >1 year. Both patients were in CR2 at time of vaccination, with duration of their remission exceeding duration of their first remission, suggesting a potential benefit. Our WT1 vaccine was well-tolerated. The clinical benefit that we observed in several patients suggests engagement of a protective immune response, indicating a need for further trials.

A phase II study of the HDAC inhibitor SB939 in patients with castration resistant prostate cancer: NCIC clinical trials group study IND195

BACKGROUND

SB939 is a potent oral inhibitor of class 1, 2, and 4 histone deacetylases (HDACs). These three HDAC classes are highly expressed in castration resistant prostate cancer (CRPC) and associated with poor clinical outcomes. We designed a phase II study of SB939 in men with metastatic CRPC.

METHODS

Patients received SB939 60 mg on alternate days three times per week for 3 weeks on a 4-week cycle. Primary endpoints were PSA response rate (RR) and progression-free survival (PFS). Secondary endpoints included objective response rate and duration; overall survival; circulating tumor cell (CTC) enumeration and safety. Exploratory correlative studies of the TMPRSS2-ERG fusion and PTEN biomarkers were also performed.

RESULTS

Thirty-two patients were enrolled of whom 88 % had received no prior chemotherapy. The median number of SB939 cycles administered was three (range 1-8). Adverse events were generally grade 1-2, with five pts experiencing one or more grade three event. One patient died due to myocardial infarction. A confirmed PSA response was noted in two pts (6 %), lasting 3.0 and 21.6 months. In patients with measurable disease there were no objective responses. Six patients had stable disease lasting 1.7 to 8.0 months. CTC response (from ≥5 at baseline to <5 at 6 or 12 weeks) occurred in 9/14 evaluable patients (64 %).

CONCLUSION

Although SB939 was tolerable at the dose/schedule given, and showed declines in CTC in the majority of evaluable patients, it did not show sufficient activity based on PSA RR to warrant further study as a single agent in unselected patients with CRPC.

Targeting histone deacetylase 6 mediates a dual anti-melanoma effect: Enhanced antitumor immunity and impaired cell proliferation

The median survival for metastatic melanoma is in the realm of 8-16 months and there are few therapies that offer significant improvement in overall survival. One of the recent advances in cancer treatment focuses on epigenetic modifiers to alter the survivability and immunogenicity of cancer cells. Our group and others have previously demonstrated that pan-HDAC inhibitors induce apoptosis, cell cycle arrest and changes in the immunogenicity of melanoma cells. Here we interrogated specific HDACs which may be responsible for this effect. We found that both genetic abrogation and pharmacologic inhibition of HDAC6 decreases in vitro proliferation and induces G1 arrest of melanoma cell lines without inducing apoptosis. Moreover, targeting this molecule led to an important upregulation in the expression of tumor associated antigens and MHC class I, suggesting a potential improvement in the immunogenicity of these cells. Of note, this anti-melanoma activity was operative regardless of mutational status of the cells. These effects translated into a pronounced delay of in vivo melanoma tumor growth which was, at least in part, dependent on intact immunity as evidenced by the restoration of tumor growth after CD4+ and CD8+ depletion. Given our findings, we provide the initial rationale for the further development of selective HDAC6 inhibitors as potential therapeutic anti-melanoma agents.

If so many are "few," how few are "many"?

The scope of reference of a word's meaning can be highly variable. We present a novel paradigm to investigate the flexible interpretation of word meaning. We focus on quantifiers such as “many” or “few,” a class of words that depends on number knowledge but can be interpreted in a flexible manner. Healthy young adults performed a truth value judgment task on pictorial arrays of varying amounts of blue and yellow circles, deciding whether the sentence “Many/few of the circles are yellow” was an adequate description of the stimulus. The study consisted of two experiments, one focusing on “many,” one on “few.” Each experiment had three blocks. In a first “baseline” block, each individual's criterion for “many” and “few” was assessed. In a second “adaptation” block, subjects received feedback about their decisions that was different from their initial judgments in an effort to evaluate the flexibility of a subject's interpretation. A third “test” block assessed whether adaptation of quantifier meaning induced in block 2 then was generalized to alter a subject's baseline meaning for “many” and “few.” In Experiment 1, a proportion of yellow circles as small as 40% was reinforced as “many”; in Experiment 2, a proportion of yellow circles as large as 60% was reinforced as “few.” Subjects learned the new criterion for “many” in Experiment 1, which also affected their criterion for “few” although it had never been mentioned. Likewise, in Experiment 2, subjects changed their criterion for “few,” with a comparable effect on the criterion for “many” which was not mentioned. Thus, the meaning of relational quantifiers like “many” and “few” is flexible and can be adapted. Most importantly, adapting the criterion for one quantifier (e.g., “many”) also appeared to affect the reciprocal quantifier (in this case, “few”). Implications of this result for psychological interventions and for investigations of the neurobiology of the language-number interface are discussed.

A phase II study of SB939, a novel pan-histone deacetylase inhibitor, in patients with translocation-associated recurrent/metastatic sarcomas-NCIC-CTG IND 200†

BACKGROUND

A subgroup of sarcomas is characterized by defining chromosomal translocations, creating fusion transcription factor oncogenes. Resultant fusion oncoproteins associate with chromatin-modifying complexes containing histone deacetylases (HDAC), and lead to epigenetic transcriptional dysregulation. HDAC inhibitors were shown to be effective in vitro, reversing gene repression by these complexes, restoring PTEN expression and apoptosis via the PI3K/Akt/mTOR pathway.

PATIENTS AND METHODS

SB939 is an oral inhibitor of classes 1 and 2 HDAC. Eligible patients with recurrent or metastatic translocation-associated sarcoma (TAS) by local pathology were treated with 60 mg/day every other day for 3 of 4 weeks. Central pathology review was conducted with fusion oncogenes characterized, and HDAC2 expression correlated with efficacy in pre-specified methods.

RESULTS

Twenty-two patients were treated with a median of 2 cycles. Fourteen patients were assessable for response with confirmed specific chromosomal translocations; 8 had a best response of stable disease (SD) (median duration 5.4 months) with no confirmed objective responses. The 3-month progression-free survival (PFS) rate was 49%. Among those with HDAC2 score ≥5, 7/10 had SD, versus 0/3 with HDAC2 score <5. SB939 was considered as well tolerated with <10% patients experienced ≥grade 3 toxicity.

CONCLUSION

This study was stopped prematurely due to prolonged unavailability of SB939. No objective responses were seen. Although the observed SD in HDAC2 high patients was interesting, due to the small sample size, no definitive conclusion can be drawn about the efficacy of SB939 in this patient population.

CLINICAL TRIAL

NCT01112384.

ALS-Plus syndrome: non-pyramidal features in a large ALS cohort

OBJECTIVE

Autopsy studies show widespread pathology in amyotrophic lateral sclerosis (ALS), but clinical surveys of multisystem disease in ALS are rare. We investigated ALS-Plus syndrome, an understudied group of patients with clinical features extending beyond pyramidal and neuromuscular systems with or without cognitive/behavioral deficits.

METHODS

In a large, consecutively-ascertained cohort of 550 patients with ALS, we documented atypical clinical manifestations. Genetic screening for C9orf72 hexanucleotide expansions was performed in 343 patients, and SOD1, TARDBP, and VCP were tested in the subgroup of patients with a family history of ALS. Gray matter and white matter imaging was available in a subgroup of 30 patients.

RESULTS

Seventy-five (13.6%) patients were identified with ALS-Plus syndrome. We found disorders of ocular motility, cerebellar, extrapyramidal and autonomic functioning. Relative to those without ALS-Plus, cognitive impairment (8.0% vs 2.9%, p=0.029), bulbar-onset (49.3% vs 23.2%, p<0.001), and pathogenic mutations (20.0% vs 8.4%, p=0.015) were more than twice as common in ALS-Plus. Survival was significantly shorter in ALS-Plus (29.66 months vs 42.50 months, p=0.02), regardless of bulbar-onset or mutation status. Imaging revealed significantly greater cerebellar and cerebral disease in ALS-Plus compared to those without ALS-Plus.

CONCLUSIONS

ALS-Plus syndrome is not uncommon, and the presence of these atypical features is consistent with neuropathological observations that ALS is a multisystem disorder. ALS-Plus syndrome is associated with increased risk for poor survival and the presence of a pathogenic mutation.

Abstract 5537: Histone deacetylase 11 (HDAC11) regulates B cell lymphopoiesis and potentiates plasma cell survival in multiple myeloma

Initially studied mainly for its role as a regulator of neural cell differentiation and development, expression of HDAC11 was once thought to be restricted exclusively to brain, kidney and testes. Hence, our recent discovery that HDAC11 acts as an important modulator of antigen presentation and T cell activation, downregulating IL-10 transcription via interactions with the IL-10 promoter at the chromatin level, exposes a previously unknown capacity and tissue specificity for this enzyme. Transgenic mice harboring an eGFP reporter construct driven by the HDAC11 promoter (Tg-HDAC11-eGFP) (Heinz, N Nat. Rev. Neuroscience 2001) clearly illustrate the dynamic changes in HDAC11 gene expression in hematopoietic cell lineages, additionally unveiling an important role for HDAC11 in B cell lymphopoiesis and plasma cell biology. While common lymphoid progenitors appear to be devoid of HDAC11 transcriptional activation as indicated by minimal detectable eGFP expression, eGFP intensity markedly increases in the B-1 stage of differentiation in the periphery. Interestingly, examination of both the bone marrow (BM) and peripheral blood (PB) plasma cell compartment demonstrates an increase in expression of eGFP/HDAC11 mRNA at the steady-state, and these results are consistent with HDAC11 expression measured in PB from healthy human subjects. Furthermore, mice globally deficient in HDAC11 expression (HDAC11KO mice) exhibit a 50% decrease in plasma cells in both the bone marrow and peripheral blood plasma cell compartments relative to wild-type mice. The concordance of HDAC11 expression and plasma cell differentiation leads us to hypothesize that HDAC11 may also be critical to malignant plasma cell survival. A comparison of normal bone marrow and malignant plasma cells isolated from multiple myeloma patient samples reveals a significantly higher level of HDAC11 expression associated with malignancy. Similar results are observed in 8 of 12 myeloma cell lines suggesting that HDAC11 expression may provide a distinct survival advantage to malignant plasma cells. Further stratification of patients into “newly diagnosed” and “proteasome inhibitor resistant” categories defines a positive correlation between HDAC11 expression and refractory disease. Treatment of the myeloma cell lines with Quisinostat, a second-generation HDAC inhibitor with enhanced selectivity for HDAC 1, 2, 4, 10 and 11 induces growth retardation at low nanomolar concentrations. Future studies will entail direct targeting of HDAC11 in myeloma cell lines and patient specimens to determine the contribution of HDAC11 to Quinsinostat activity. Taken together, we have unveiled a previously unknown role for HDAC11 in plasma cell differentiation and survival. The demonstration of HDAC11 overexpression in primary human myeloma cells provides a framework for therapeutics targeting this HDAC in multiple myeloma.

Citation Format: Eva Sahakian, Jason Brayer, John Powers, Mark Meads, Susan Deng, Allison Distler, Melissa Alsina, Taiga Nishihori, Rachid Baz, Alejandro Villagra, Javier Pinilla-Ibarz, Eduardo Sotomayor, Kenneth Shain. Histone deacetylase 11 (HDAC11) regulates B cell lymphopoiesis and potentiates plasma cell survival in multiple myeloma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5537. doi:10.1158/1538-7445.AM2014-5537

Abstract 4090: Inhibition of class I histone deacetylases promotes robust and durable enhancement of PDL1 expression in melanoma: Rationale for combination therapy

Histone deacetylase inhibitors (HDACi) have shown remarkable anti-tumor activity, leading to FDA approval of two HDACi for the treatment of CTCL and several others currently at various stages of clinical development for the treatment of both solid and hematological malignancies. Previous work from our lab has shown that treatment with HDACi results in increased expression of pro-inflammatory promoting surface markers on melanoma cells, promoting enhanced T-cell activation. Recent clinical trial data has shown that blockade of the PD1/PDL1 interaction is effective in the treatment of melanoma, renal cell and non-small cell lung cancer. Importantly, responses to PD1 blocking antibodies were preferentially seen in patients with tumors expressing PDL1. Here we report that HDACi targeting class I HDACs, but not class II, augments expression of PDL1 in melanoma cells. Two murine and five human melanoma cell lines were treated for up to 72 hours with DMSO, LBH589 (pan-HDACi), MS275 (class I inhibitor), MGCD0103 (class I inhibitor), an HDAC6 specific inhibitor, or a class IIa inhibitor. Using flow cytometry, dose dependent, increases in PDL1 expression were found in the LBH589, MS275 and MGCD0103 treated groups, but not in those receiving HDAC6i or class IIa inhibitor, relative to DMSO. Increased expression was noted as early as 24 hours after treatment and peaked at 72 to 96 hours post-treatment. As IFN-γ is known to upregulate the expression of PDL1 in both normal and transformed cells, we evaluated whether these results were associated with induction of IFN-γ expression by the melanoma cells. However, no detectable levels of IFN-γ were seen in either non-treated, class I HDACi, or class II HDACi-treated cells. Melanoma cells treated with HDACi in addition to IFN-γ have enhanced expression of PDL1 relative to either treatment alone. To further gain insight into the specific HDAC regulating the expression of PDL1, preliminary experiments utilizing knockdowns (KD) of individual class I HDACs were performed. In all KD melanoma cells no increase in PDL1 expression was seen, suggesting that the increased expression of PDL1 is dependent on inhibition of multiple class I HDACs. Supporting this conclusion, treatment of class I HDAC-KDs with HDACi recapitulates the increased PDL1 expression seen with WT melanoma. Finally, in preliminary in vivo experiments combining treatment of melanoma bearing mice with anti-PDL1 antibodies, mice receiving the combination treatment had a survival advantage over those receiving PDL1 blocking antibodies or HDACi alone. These results provide a strong rationale for the evaluation of combination therapies utilizing PDL1 or PD1 blocking antibodies in combination with HDACi. Furthermore, these results support the need for further development and investigation of iso-specific HDACi in order to obtain more directed therapeutic efficacy.

Citation Format: David M. Woods, Andressa L. Sodre, Eva Sahakian, John Powers, Maritza Lienlaf-Moreno, Patricio Perez-Villarroel, Alejandro Villagra, Javier Pinilla-Ibarz, Eduardo Sotomayor. Inhibition of class I histone deacetylases promotes robust and durable enhancement of PDL1 expression in melanoma: Rationale for combination therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4090. doi:10.1158/1538-7445.AM2014-4090

Myelin oligodendrocyte basic protein and prognosis in behavioral-variant frontotemporal dementia

OBJECTIVE

To determine the prognostic utility of tauopathy-associated single nucleotide polymorphisms (SNPs) in sporadic behavioral-variant frontotemporal dementia (bvFTD).

METHODS

Eighty-one patients with sporadic bvFTD were genotyped for tauopathy-associated SNPs at rs8070723 (microtubule-associated protein tau [MAPT]) and rs1768208 (myelin-associated oligodendrocyte basic protein [MOBP]). We performed a retrospective case-control study comparing age at onset and disease duration between carriers of ≥1 polymorphism allele and noncarriers for these SNPs. Subanalyses were performed for autopsied subgroups with tauopathy (n = 20) and TDP-43 proteinopathy (n = 12). To identify a potential biological basis for disease duration, neuroimaging measures of white matter integrity were evaluated (n = 37).

RESULTS

Carriers of risk allele (T) in rs1768208 (i.e., MOBP RA+) had a shorter median disease duration (TC/TT = 5.5 years, CC = 9.5 years; p = 0.02). This was also found in the subset of cases with autopsy-confirmed tauopathies (p = 0.04) but not with TDP-43 proteinopathies (p > 0.1). By comparison, polymorphisms at rs8070723 (MAPT) had no effect on disease duration (p > 0.1), although carriers of protective allele (G) in rs8070723 had a younger median age at onset (AG/GG = 54.5 years, AA = 58 years; p < 0.01). MOBP RA+ patients had increased radial diffusivity in the superior corona radiata and midbrain, and reduced fractional anisotropy in the superior corona radiata as well as superior and inferior longitudinal fasciculi compared with noncarriers (p < 0.01).

CONCLUSIONS

The rs1768208 risk polymorphism in MOBP may have prognostic value in bvFTD. MOBP RA+ patients have more severe white matter degeneration in bvFTD that may contribute to shorter disease duration. Future studies are needed to help confirm these findings.

Phosphorylated tau as a candidate biomarker for amyotrophic lateral sclerosis

IMPORTANCE

An increasingly varied clinical spectrum of cases with amyotrophic lateral sclerosis (ALS) has been identified, and objective criteria for clinical trial eligibility are necessary.

OBJECTIVE

To develop a cerebrospinal fluid (CSF) biomarker sensitive and specific for the diagnosis of ALS.

DESIGN, SETTING, AND PARTICIPANTS

A case-control study including 51 individuals with ALS and 23 individuals with a disorder associated with a 4-repeat tauopathy was conducted at an academic medical center.

MAIN OUTCOMES AND MEASURES

The CSF level of tau phosphorylated at threonine 181 (ptau) and ratio of ptau to total tau (ttau).

RESULTS

Using a cross-validation prediction procedure, we found significantly reduced CSF levels of ptau and the ptau:ttau ratio in ALS relative to 4-repeat tauopathy and to controls. In the validation cohort, the receiver operating characteristic area under the curve for the ptau:ttau ratio was 0.916, and the comparison of ALS with 4-repeat tauopathy showed 92.0% sensitivity and 91.7% specificity. Correct classification based on a low CSF ptau:ttau ratio was confirmed in 18 of 21 cases (86%) with autopsy-proved or genetically determined disease. In patients with available measures, ptau:ttau in ALS correlated with clinical measures of disease severity, such as the Mini-Mental State Examination (n = 51) and ALS Functional Rating Scale-Revised (n = 42), and regression analyses related the ptau:ttau ratio to magnetic resonance imaging (n = 10) evidence of disease in the corticospinal tract and white matter projections involving the prefrontal cortex.

CONCLUSIONS AND RELEVANCE

The CSF ptau:ttau ratio may be a candidate biomarker to provide objective support for the diagnosis of ALS.

Grammatical comprehension deficits in non-fluent/agrammatic primary progressive aphasia

IMPORTANCE

Grammatical comprehension difficulty is an essential supporting feature of the non-fluent/agrammatic variant of primary progressive aphasia (naPPA), but well-controlled clinical measures of grammatical comprehension are unavailable.

OBJECTIVE

To develop a measure of grammatical comprehension and examine this comparatively in PPA variants and behavioural-variant frontotemporal degeneration (bvFTD) and to assess the neuroanatomic basis for these deficits with volumetric grey matter atrophy and whole-brain fractional anisotropy (FA) in white matter tracts.

DESIGN

Case-control study.

SETTING

Academic medical centre.

PARTICIPANTS

39 patients with variants of PPA (naPPA=12, lvPPA=15 and svPPA=12), 27 bvFTD patients without aphasia and 12 healthy controls.

MAIN OUTCOME MEASURE

Grammatical comprehension accuracy.

RESULTS

Patients with naPPA had selective difficulty understanding cleft sentence structures, while all PPA variants and patients with bvFTD were impaired with sentences containing a centre-embedded subordinate clause. Patients with bvFTD were also impaired understanding sentences involving short-term memory. Linear regressions related grammatical comprehension difficulty in naPPA to left anterior-superior temporal atrophy and reduced FA in corpus callosum and inferior frontal-occipital fasciculus. Difficulty with centre-embedded sentences in other PPA variants was related to other brain regions.

CONCLUSIONS AND RELEVANCE

These findings emphasise a distinct grammatical comprehension deficit in naPPA and associate this with interruption of a frontal-temporal neural network.

Genetic and neuroanatomic associations in sporadic frontotemporal lobar degeneration

Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) that are sensitive for tau or TDP-43 pathology in frontotemporal lobar degeneration (FTLD). Neuroimaging analyses have revealed distinct distributions of disease in FTLD patients with genetic mutations. However, genetic influences on neuroanatomic structure in sporadic FTLD have not been assessed. In this report, we use novel multivariate tools, Eigenanatomy, and sparse canonical correlation analysis to identify associations between SNPs and neuroanatomic structure in sporadic FTLD. Magnetic resonance imaging analyses revealed that rs8070723 (MAPT) was associated with gray matter variance in the temporal cortex. Diffusion tensor imaging analyses revealed that rs1768208 (MOBP), rs646776 (near SORT1), and rs5848 (PGRN) were associated with white matter variance in the midbrain and superior longitudinal fasciculus. In an independent autopsy series, we observed that rs8070723 and rs1768208 conferred significant risk of tau pathology relative to TDP-43, and rs646776 conferred increased risk of TDP-43 pathology relative to tau. Identified brain regions and SNPs may help provide an in vivo screen for underlying pathology in FTLD and contribute to our understanding of sporadic FTLD.

Tensile bond strength of four denture resins to porcelain teeth with different surface treatment

PURPOSE

This study evaluated the bond strength between porcelain denture teeth (Bioblend 43D) and four different polymerized denture resins (Lucitone 199, Palapress, Acron MC, Triad) with and without a bonding agent and after four different types of surface treatment (polished, HF etched, sandblasted, air-abraded).

MATERIALS AND METHODS

Central incisor porcelain denture teeth were divided into 32 groups of 5 each. Tensile bond strength (MPa) was determined using a testing machine at crosshead speed of 0.5 mm/min. Mean and standard deviation are listed. Data were analyzed by two-way ANOVA. Means were compared by Tukey-Kramer intervals at 0.05 significance level.

RESULTS

All surface treatment increased bond strength compared to polished surface and the highest bond strength was found with Palapress resin with etched porcelain surface (8.1 MPa). Bonding agent improved the bond strength of all denture resins to porcelain teeth. Superior bonding was found with Palapress and air-abraded porcelain (39 MPa).

CONCLUSION

Resins with different curing methods affect the bond strength of porcelain teeth to denture bases. Superior bonding was found with auto-polymerized resin (Palapress). Application of ceramic primer and bonding agent to porcelain teeth with and without surface treatment will improve the bond strength of all denture resins to porcelain teeth.

Disruption of large-scale neural networks in non-fluent/agrammatic variant primary progressive aphasia associated with frontotemporal degeneration pathology

Non-fluent/agrammatic primary progressive aphasia (naPPA) is a progressive neurodegenerative condition most prominently associated with slowed, effortful speech. A clinical imaging marker of naPPA is disease centered in the left inferior frontal lobe. We used multimodal imaging to assess large-scale neural networks underlying effortful expression in 15 patients with sporadic naPPA due to frontotemporal lobar degeneration (FTLD) spectrum pathology. Effortful speech in these patients is related in part to impaired grammatical processing, and to phonologic speech errors. Gray matter (GM) imaging shows frontal and anterior-superior temporal atrophy, most prominently in the left hemisphere. Diffusion tensor imaging reveals reduced fractional anisotropy in several white matter (WM) tracts mediating projections between left frontal and other GM regions. Regression analyses suggest disruption of three large-scale GM-WM neural networks in naPPA that support fluent, grammatical expression. These findings emphasize the role of large-scale neural networks in language, and demonstrate associated language deficits in naPPA.

Age-related vulnerability in the neural systems supporting semantic processing

Our ability to form abstract representations of objects in semantic memory is crucial to language and thought. The utility of this information relies both on the representations of sensory-motor feature knowledge stored in long-term memory and the executive processes required to retrieve, manipulate, and evaluate this semantic knowledge in a task-relevant manner. These complementary components of semantic memory can be differentially impacted by aging. We investigated semantic processing in normal aging using functional magnetic resonance imaging (fMRI). Young and older adults were asked to judge whether two printed object names match on a particular feature (for example, whether a tomato and strawberry have the same color). The task thus required both retrieval of relevant visual feature knowledge of object concepts and evaluating this information. Objects were drawn from either natural kinds or manufactured objects, and were queried on either color or shape in a factorial design. Behaviorally, all subjects performed well, but older adults could be divided into those whose performance matched that of young adults (better performers) and those whose performance was worse (poorer performers). All subjects activated several cortical regions while performing this task, including bilateral inferior and lateral temporal cortex and left frontal and prefrontal cortex. Better performing older adults showed increased overall activity in bilateral premotor cortex and left lateral occipital cortex compared to young adults, and increased activity in these brain regions relative to poorer performing older adults who also showed gray matter atrophy in premotor cortex. These findings highlight the contribution of domain-general executive processing brain regions to semantic memory, and illustrate differences in how these regions are recruited in healthy older adults.

White matter imaging helps dissociate tau from TDP-43 in frontotemporal lobar degeneration

BACKGROUND

Frontotemporal lobar degeneration (FTLD) is most commonly associated with TAR-DNA binding protein (TDP-43) or tau pathology at autopsy, but there are no in vivo biomarkers reliably discriminating between sporadic cases. As disease-modifying treatments emerge, it is critical to accurately identify underlying pathology in living patients so that they can be entered into appropriate etiology-directed clinical trials. Patients with tau inclusions (FTLD-TAU) appear to have relatively greater white matter (WM) disease at autopsy than those patients with TDP-43 (FTLD-TDP). In this paper, we investigate the ability of white matter (WM) imaging to help discriminate between FTLD-TAU and FTLD-TDP during life using diffusion tensor imaging (DTI).

METHODS

Patients with autopsy-confirmed disease or a genetic mutation consistent with FTLD-TDP or FTLD-TAU underwent multimodal T1 volumetric MRI and diffusion weighted imaging scans. We quantified cortical thickness in GM and fractional anisotropy (FA) in WM. We performed Eigenanatomy, a statistically robust dimensionality reduction algorithm, and used leave-one-out cross-validation to predict underlying pathology. Neuropathological assessment of GM and WM disease burden was performed in the autopsy-cases to confirm our findings of an ante-mortem GM and WM dissociation in the neuroimaging cohort.

RESULTS

ROC curve analyses evaluated classification accuracy in individual patients and revealed 96% sensitivity and 100% specificity for WM analyses. FTLD-TAU had significantly more WM degeneration and inclusion severity at autopsy relative to FTLD-TDP.

CONCLUSIONS

These neuroimaging and neuropathological investigations provide converging evidence for greater WM burden associated with FTLD-TAU, and emphasise the role of WM neuroimaging for in vivo discrimination between FTLD-TAU and FTLD-TDP.

Comparative semantic profiles in semantic dementia and Alzheimer's disease

Patients with the semantic variant of primary progressive aphasia, also known as semantic dementia, and Alzheimer's disease have deficits in semantic memory. However, few comparative studies have been performed to determine whether these patient groups have distinct semantic memory impairments. We asked 15 patients with semantic variant primary progressive aphasia and 57 patients with Alzheimer's disease to judge semantic category membership of coloured photos and printed words that are members of familiar natural and manufactured categories, and we related performance to grey matter atrophy. We found that both semantic variant primary progressive aphasia and Alzheimer's disease are significantly impaired on this task. Moreover, patients with semantic variant primary progressive aphasia had a significantly more prominent deficit for natural objects than their own deficit judging manufactured objects. Both semantic variant primary progressive aphasia and Alzheimer's disease had atrophy that included portions of the left temporal lobe. Regression analyses related performance in semantic variant primary progressive aphasia to ventral and medial portions of the left temporal lobe, while regression analyses in Alzheimer's disease related performance to these ventral and medial temporal areas as well as lateral temporal-parietal regions in the left hemisphere. We conclude that both semantic variant primary progressive aphasia and Alzheimer's disease are significantly impaired in a simple category membership judgement task and the selective impairment for natural kinds in semantic variant primary progressive aphasia is related in part to disease in visual association cortex in ventral-medial portions of the left temporal lobe. We discuss factors that may contribute to the semantic memory deficit in semantic variant primary progressive aphasia.

Differentiating primary progressive aphasias in a brief sample of connected speech

OBJECTIVE

A brief speech expression protocol that can be administered and scored without special training would aid in the differential diagnosis of the 3 principal forms of primary progressive aphasia (PPA): nonfluent/agrammatic PPA, logopenic variant PPA, and semantic variant PPA.

METHODS

We used a picture-description task to elicit a short speech sample, and we evaluated impairments in speech-sound production, speech rate, lexical retrieval, and grammaticality. We compared the results with those obtained by a longer, previously validated protocol and further validated performance with multimodal imaging to assess the neuroanatomical basis of the deficits.

RESULTS

We found different patterns of impaired grammar in each PPA variant, and additional language production features were impaired in each: nonfluent/agrammatic PPA was characterized by speech-sound errors; logopenic variant PPA by dysfluencies (false starts and hesitations); and semantic variant PPA by poor retrieval of nouns. Strong correlations were found between this brief speech sample and a lengthier narrative speech sample. A composite measure of grammaticality and other measures of speech production were correlated with distinct regions of gray matter atrophy and reduced white matter fractional anisotropy in each PPA variant.

CONCLUSIONS

These findings provide evidence that large-scale networks are required for fluent, grammatical expression; that these networks can be selectively disrupted in PPA syndromes; and that quantitative analysis of a brief speech sample can reveal the corresponding distinct speech characteristics.

Histone deacetylase 11 is an epigenetic regulator of cytotoxic T-lymphocyte effector function and memory formation (P1404)

The roles of individual histone deacetylases in the regulation of T-cell development and function remain largely unknown. Here we provide evidence for HDAC11 as an epigenetic regulator of T-cell inflammatory response as well as CTL central memory formation. To investigate the role of HDAC11 in T-cells, an HDAC11 knockout (HDAC11KO) mouse model was utilized. HDAC11KO mice display no gross phenotypic abnormalities and no alterations in T-cell development or CD4+/CD8+ population distributions. However, HDAC11KO CTLs are hyper-proliferative and secrete significantly higher levels of IL-2, TNF, and IFN-γ upon activation, and HDAC11KO mice accumulate higher percentages of central memory CTLs. In an allogeneic bone marrow transfer model, HDAC11KO T-cells mediate more potent and robust graft vs host disease associated with increased inflammatory cytokines. Mechanistically, we provide evidence that in CTLs HDAC11 interacts with the Eomes gene promoter, a known regulator of IFN-γ production and memory formation. HDAC11KO CTLs, at both basal state and post stimulation, display higher levels of acetylation at the Eomes promoter, indicative of a permissive transcriptional state. Correspondingly, eomes mRNA levels in HDAC11KO cells are elevated. Finally, chromatin immunoprecipitation of HDAC11 reveals interaction between HDAC11 and the Eomes promoter in CTLs. These results support HDAC11 as an epigenetic regulator of CTL function and memory formation through epigenetic regulation of Eomes.

Research to improve extension ladder angular positioning

A leading cause for extension ladder fall incidents is a slide-out event usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury. The objective of the study was to comparatively evaluate the effectiveness of a multimodal angle indicator with other existing methods for extension ladder angular positioning. Twenty experienced and 20 inexperienced ladder users participated in the study. Four ladder positioning methods were tested in a controlled laboratory environment with 4.88 m (16 ft) and 7.32 m (24 ft) ladders in extended and retracted positions. The positioning methods included a no-instruction method, the current standard anthropometric method, and two instrumental methods - a bubble level indicator, and a multimodal indicator providing direct feedback with visual and sound signals. Performance measures included positioning angle and time. The results indicated that the anthropometric method was effective in improving the extension ladder positioning angle (p < 0.001); however, it was associated with considerable variability and required 50% more time than no-instruction. The bubble level indicator was an accurate positioning method (with very low variability), but required more than double the time of the no-instruction method (p < 0.001). The multimodal indicator improved the ladder angle setting as compared to the no-instruction and anthropometry methods (p < 0.001) and required the least time for ladder positioning among the tested methods (p < 0.001). An indicator with direct multimodal feedback is a viable approach for quick and accurate ladder positioning. The main advantage of the new multimodal method is that it provides continuous feedback on the angle of the device and hence does not require repositioning of the ladder. Furthermore, this indicator can be a valuable tool for training ladder users to correctly apply the current ANSI A14 standard anthropometric method in ladder angular positioning. The multimodal indicator concept has been further developed to become a hand-held tool in the form of a smart phone application.