Alzheimer's Disease Pathophysiology in the Retina.

The retina is an emerging CNS target for potential noninvasive diagnosis and tracking of Alzheimer's disease (AD). Studies have identified the pathological hallmarks of AD, including amyloid ß-protein (Aß) deposits and abnormal tau protein isoforms, in the retinas of AD patients and animal models. Moreover, structural and functional vascular abnormalities such as reduced blood flow, vascular Aß deposition, and blood-retinal barrier damage, along with inflammation and neurodegeneration, have been described in retinas of patients with mild cognitive impairment and AD dementia. Histological, biochemical, and clinical studies have demonstrated that the nature and severity of AD pathologies in the retina and brain correspond. Proteomics analysis revealed a similar pattern of dysregulated proteins and biological pathways in the retina and brain of AD patients, with enhanced inflammatory and neurodegenerative processes, impaired oxidative-phosphorylation, and mitochondrial dysfunction. Notably, investigational imaging technologies can now detect AD-specific amyloid deposits, as well as vasculopathy and neurodegeneration in the retina of living AD patients, suggesting alterations at different disease stages and links to brain pathology. Current and exploratory ophthalmic imaging modalities, such as optical coherence tomography (OCT), OCT-angiography, confocal scanning laser ophthalmoscopy, and hyperspectral imaging, may offer promise in the clinical assessment of AD. However, further research is needed to deepen our understanding of AD's impact on the retina and its progression. To advance this field, future studies require replication in larger and diverse cohorts with confirmed AD biomarkers and standardized retinal imaging techniques. This will validate potential retinal biomarkers for AD, aiding in early screening and monitoring.

Distinctive retinal peri-arteriolar versus peri-venular amyloid plaque distribution correlates with the cognitive performance.

Introduction: The vascular contribution to Alzheimer's disease (AD) is tightly connected to cognitive performance across the AD continuum. We topographically describe retinal perivascular amyloid plaque (AP) burden in subjects with normal or impaired cognition. Methods: Using scanning laser ophthalmoscopy, we quantified retinal peri-arteriolar and peri-venular curcumin-positive APs in the first, secondary and tertiary branches in twenty-eight subjects. Perivascular AP burden among cognitive states was correlated with neuroimaging and cognitive measures. Results: Peri-arteriolar exceeded peri-venular AP count (p<0.0001). Secondary branch AP count was significantly higher in cognitively impaired (p<0.01). Secondary small and tertiary peri-venular AP count strongly correlated with clinical dementia rating, hippocampal volumes, and white matter hyperintensity count. Discussion: Our topographic analysis indicates greater retinal amyloid accumulation in the retinal peri-arteriolar regions overall, and distal peri-venular regions in cognitively impaired individuals. Larger longitudinal studies are warranted to understand the temporal-spatial relationship between vascular dysfunction and perivascular amyloid deposition in AD. Highlights: Retinal peri-arteriolar region exhibits more amyloid compared with peri-venular regions.Secondary retinal vascular branches have significantly higher perivascular amyloid burden in subjects with impaired cognition, consistent across sexes.Cognitively impaired individuals have significantly greater retinal peri-venular amyloid deposits in the distal small branches, that correlate with CDR and hippocampal volumes.

Antigen-specific age-related memory CD8 T cells induce and track Alzheimer's-like neurodegeneration.

Cerebral (Aß) plaque and (pTau) tangle deposition are hallmarks of Alzheimer's disease (AD), yet are insufficient to confer complete AD-like neurodegeneration experimentally. Factors acting upstream of Aß/pTau in AD remain unknown, but their identification could enable earlier diagnosis and more effective treatments. T cell abnormalities are emerging AD hallmarks, and CD8 T cells were recently found to mediate neurodegeneration downstream of tangle deposition in hereditary neurodegeneration models. The precise impact of T cells downstream of Aß/fibrillar pTau, however, appears to vary depending on the animal model used. Our prior work suggested that antigen-specific memory CD8 T (" hi T") cells act upstream of Aß/pTau after brain injury. Here we examine whether hi T cells influence sporadic AD-like pathophysiology upstream of Aß/pTau. Examining neuropathology, gene expression, and behavior in our hi T mouse model we show that CD8 T cells induce plaque and tangle-like deposition, modulate AD-related genes, and ultimately result in progressive neurodegeneration with both gross and fine features of sporadic human AD. T cells required Perforin to initiate this pathophysiology, and IFNγ for most gene expression changes and progression to more widespread neurodegenerative disease. Analogous antigen-specific memory CD8 T cells were significantly elevated in the brains of human AD patients, and their loss from blood corresponded to sporadic AD and related cognitive decline better than plasma pTau-217, a promising AD biomarker candidate. Our work is the first to identify an age-related factor acting upstream of Aß/pTau to initiate AD-like pathophysiology, the mechanisms promoting its pathogenicity, and its relevance to human sporadic AD. Significance Statement: This study changes our view of Alzheimer's Disease (AD) initiation and progression. Mutations promoting cerebral beta-amyloid (Aß) deposition guarantee rare genetic forms of AD. Thus, the prevailing hypothesis has been that Aß is central to initiation and progression of all AD, despite contrary animal and patient evidence. We show that age-related T cells generate neurodegeneration with compelling features of AD in mice, with distinct T cell functions required for pathological initiation and neurodegenerative progression. Knowledge from these mice was applied to successfully predict previously unknown features of human AD and generate novel tools for its clinical management.

Identification of retinal tau oligomers, citrullinated tau, and other tau isoforms in early and advanced AD and relations to disease status.

Importance: This study identifies and quantifies diverse pathological tau isoforms in the retina of both early and advanced-stage Alzheimer's disease (AD) and determines their relationship with disease status. Objective: A case-control study was conducted to investigate the accumulation of retinal neurofibrillary tangles (NFTs), paired helical filament (PHF)-tau, oligomeric tau (oligo-tau), hyperphosphorylated tau (p-tau), and citrullinated tau (Cit-tau) in relation to the respective brain pathology and cognitive dysfunction in mild cognitively impaired (MCI) and AD dementia patients versus normal cognition (NC) controls. Design setting and participants: Eyes and brains from donors diagnosed with AD, MCI (due to AD), and NC were collected (n=75 in total), along with clinical and neuropathological data. Brain and retinal cross-sections-in predefined superior-temporal and inferior-temporal (ST/IT) subregions-were subjected to histopathology analysis or Nanostring GeoMx digital spatial profiling. Main outcomes and measure: Retinal burden of NFTs (pretangles and mature tangles), PHF-tau, p-tau, oligo-tau, and Cit-tau was assessed in MCI and AD versus NC retinas. Pairwise correlations revealed associations between retinal and brain parameters and cognitive status. Results: Increased retinal NFTs (1.8-fold, p=0.0494), PHF-tau (2.3-fold, p<0.0001), oligo-tau (9.1-fold, p<0.0001), CitR 209 -tau (4.3-fold, p<0.0001), pSer202/Thr205-tau (AT8; 4.1-fold, p<0.0001), and pSer396-tau (2.8-fold, p=0.0015) were detected in AD patients. Retinas from MCI patients showed significant increases in NFTs (2.0-fold, p=0.0444), CitR 209 -tau (3.5-fold, p=0.0201), pSer396-tau (2.6-fold, p=0.0409), and, moreover, oligo-tau (5.8-fold, p=0.0045). Nanostring GeoMx quantification demonstrated upregulated retinal p-tau levels in MCI patients at phosphorylation sites of Ser214 (2.3-fold, p=0.0060), Ser396 (1.8-fold, p=0.0052), Ser404 (2.4-fold, p=0.0018), and Thr231 (3.3-fold, p=0.0028). Strong correlations were found between retinal tau forms to paired-brain pathology and cognitive status: a) retinal oligo-tau vs. Braak stage (r=0.60, P=0.0002), b) retinal PHF-tau vs. ABC average score (r=0.64, P=0.0043), c) retinal pSer396-tau vs. brain NFTs (r=0.68, P<0.0001), and d) retinal pSer202/Thr205-tau vs. MMSE scores (r= -0.77, P=0.0089). Conclusions and Relevance: This study reveals increases in immature and mature retinal tau isoforms in MCI and AD patients, highlighting their relationship with brain pathology and cognition. The data provide strong incentive to further explore retinal tauopathy markers that may be useful for early detection and monitoring of AD staging through noninvasive retinal imaging.

Meningioma transformation to glioblastoma following stereotactic radiosurgery: A case report and review of the literature.

Background: Meningiomas are the most common primary intracranial tumor with increasing incidence. Stereotactic Radiosurgery Gamma Knife (SRS-GK) is a commonly used modality for neoadjuvant and adjuvant treatment of these tumors and is often necessary for long-term disease control, particularly for the World Health Organization grade II/III meningiomas. While there is strong evidence to support the use of SRS-GK for meningioma, there exists a risk of secondary malignancy that is not well understood. We report a case of glioblastoma (GBM) that arose near the bed of a meningioma previously treated with SRS-GK and discuss other cases of GBM that emerged at a site of meningioma reported in the literature. Case Description: A 79-year-old female with a history of a blood-clotting disorder presented to the hospital with sudden facial sensory disturbances. On magnetic resonance imaging (MRI), a homogeneously enhancing lesion was observed in the right temporal lobe, consistent with a meningioma. Following 2 years of surveillance, the patient underwent SRS-GK for enlargement of the lesion. The patient later presented with headache and gait instability 12 years following SRS-GK. MRI revealed a large ring-enhancing lesion with surrounding edema histologically confirmed to be a GBM. At 9 months following initial tumor resection and a combination of radiotherapy and temozolomide, the patient was neurologically intact. Conclusion: There is a very small risk of meningioma to GBM conversion following SRS. Although SRS-GK poses a risk of secondary malignancy, there are some reported cases that underwent malignant transformation without SRS-GK. This suggests that SRS-GK is not the only factor in transformation and is a reasonable therapeutic modality to consider utilizing. Patients and their families should be appropriately counseled on the potential risks of radiation therapy, even for benign lesions like a meningioma.

Exposure to environmental airborne particulate matter caused wide-ranged transcriptional changes and accelerated Alzheimer's-related pathology: A mouse study.

Air pollution poses a significant threat to human health, though a clear understanding of its mechanism remains elusive. In this study, we sought to better understand the effects of various sized particulate matter from polluted air on Alzheimer's disease (AD) development using an AD mouse model. We exposed transgenic Alzheimer's mice in their prodromic stage to different sized particulate matter (PM), with filtered clean air as control. After 3 or 6 months of exposure, mouse brains were harvested and analyzed. RNA-seq analysis showed that various PM have differential effects on the brain transcriptome, and these effects seemed to correlate with PM size. Many genes and pathways were affected after PM exposure. Among them, we found a strong activation in mRNA Nonsense Mediated Decay pathway, an inhibition in pathways related to transcription, neurogenesis and survival signaling as well as angiogenesis, and a dramatic downregulation of collagens. Although we did not detect any extracellular Aß plaques, immunostaining revealed that both intracellular Aß1-42 and phospho-Tau levels were increased in various PM exposure conditions compared to the clean air control. NanoString GeoMx analysis demonstrated a remarkable activation of immune responses in the PM exposed mouse brain. Surprisingly, our data also indicated a strong activation of various tumor suppressors including RB1, CDKN1A/p21 and CDKN2A/p16. Collectively, our data demonstrated that exposure to airborne PM caused a profound transcriptional dysregulation and accelerated Alzheimer's-related pathology.

ß-Amyloid targeting nanodrug for neuron-specific delivery of nucleic acids in Alzheimer's disease mouse models.

Delivery of therapeutic substances into the brain poses a significant challenge in the treatment of neurological disorders. This is primarily due to the blood-brain barrier (BBB), which restricts access, alongside the limited stability and distribution of these agents within the brain tissue. Here we demonstrate an efficient delivery of microRNA (miRNA) and antisense RNA preferentially to neurons compared to astroglia in the brain of healthy and Alzheimer's disease mice, via disulfide-linked conjugation with poly(ß-L-malic acid-trileucine)-copolymer a biodegradable, amphiphilic, and multivalent platform. By conjugating a D-configured (D3)-peptide (vector) for specific targeting, highly efficient delivery across the BBB is achieved through the Low-Density Lipoprotein Receptor-Related Protein-1 (LRP-1) transcytosis pathway, amyloid beta (Aß) peptides. Nanodrug distribution was determined by fluorescent labeling and analyzed by microscopy in neurons, astroglia, and in extracellular amyloid plaques typical for Alzheimer's disease. Whereas D-configured BBB-vectors can efficiently target neurons, L-configured (e.g., AP2-peptide) guided vector can only cross BBB but not seem to bind neurons. An analysis of post-injection fluorescence distribution, and RNA-seq followed by real-time PCR validation, confirmed a successful in vivo delivery of morpholino-miRNA-186 nanoconjugates into mouse brain. The size and fluorescence intensity of the intracellular nanodrug particulates were analyzed and verified by a competition with non-fluorescent conjugates. Differentially expressed genes (DEGs) from RNA-seq were identified in the nanodrug injected mice, and the changes of selected DEGs related to Alzheimer's disease were further validated by western blot and real-time PCR. Collectively, these results demonstrated that D3-peptide-conjugated nanopolymer drug is able to achieve neuron-selective delivery of miRNA and can serve as an efficient brain delivery vehicle in Alzheimer's disease (AD) mouse models.

The effects of enhancing angiotensin converting enzyme in myelomonocytes on ameliorating Alzheimer's-related disease and preserving cognition.

This review examines the role of angiotensin-converting enzyme (ACE) in the context of Alzheimer's disease (AD) and its potential therapeutic value. ACE is known to degrade the neurotoxic 42-residue long alloform of amyloid ß-protein (Aß42), a peptide strongly associated with AD. Previous studies in mice, demonstrated that targeted overexpression of ACE in CD115+ myelomonocytic cells (ACE10 models) improved their immune responses to effectively reduce viral and bacterial infection, tumor growth, and atherosclerotic plaque. We further demonstrated that introducing ACE10 myelomonocytes (microglia and peripheral monocytes) into the double transgenic APPSWE/PS1ΔE9 murine model of AD (AD+ mice), diminished neuropathology and enhanced the cognitive functions. These beneficial effects were dependent on ACE catalytic activity and vanished when ACE was pharmacologically blocked. Moreover, we revealed that the therapeutic effects in AD+ mice can be achieved by enhancing ACE expression in bone marrow (BM)-derived CD115+ monocytes alone, without targeting central nervous system (CNS) resident microglia. Following blood enrichment with CD115+ ACE10-monocytes versus wild-type (WT) monocytes, AD+ mice had reduced cerebral vascular and parenchymal Aß burden, limited microgliosis and astrogliosis, as well as improved synaptic and cognitive preservation. CD115+ ACE10-versus WT-monocyte-derived macrophages (Mo/MΦ) were recruited in higher numbers to the brains of AD+ mice, homing to Aß plaque lesions and exhibiting a highly Aß-phagocytic and anti-inflammatory phenotype (reduced TNFα/iNOS and increased MMP-9/IGF-1). Moreover, BM-derived ACE10-Mo/MΦ cultures had enhanced capability to phagocytose Aß42 fibrils, prion-rod-like, and soluble oligomeric forms that was associated with elongated cell morphology and expression of surface scavenger receptors (i.e., CD36, Scara-1). This review explores the emerging evidence behind the role of ACE in AD, the neuroprotective properties of monocytes overexpressing ACE and the therapeutic potential for exploiting this natural mechanism for ameliorating AD pathogenesis.

Osteopontin depletion in macrophages perturbs proteostasis via regulating UCHL1-UPS axis and mitochondria-mediated apoptosis.

Introduction: Osteopontin (OPN; also known as SPP1), an immunomodulatory cytokine highly expressed in bone marrow-derived macrophages (BMMΦ), is known to regulate diverse cellular and molecular immune responses. We previously revealed that glatiramer acetate (GA) stimulation of BMMΦ upregulates OPN expression, promoting an anti-inflammatory, pro-healing phenotype, whereas OPN inhibition triggers a pro-inflammatory phenotype. However, the precise role of OPN in macrophage activation state is unknown. Methods: Here, we applied global proteome profiling via mass spectrometry (MS) analysis to gain a mechanistic understanding of OPN suppression versus induction in primary macrophage cultures. We analyzed protein networks and immune-related functional pathways in BMMΦ either with OPN knockout (OPNKO) or GA-mediated OPN induction compared with wild type (WT) macrophages. The most significant differentially expressed proteins (DEPs) were validated using immunocytochemistry, western blot, and immunoprecipitation assays. Results and discussion: We identified 631 DEPs in OPNKO or GA-stimulated macrophages as compared to WT macrophages. The two topmost downregulated DEPs in OPNKO macrophages were ubiquitin C-terminal hydrolase L1 (UCHL1), a crucial component of the ubiquitin-proteasome system (UPS), and the anti-inflammatory Heme oxygenase 1 (HMOX-1), whereas GA stimulation upregulated their expression. We found that UCHL1, previously described as a neuron-specific protein, is expressed by BMMΦ and its regulation in macrophages was OPN-dependent. Moreover, UCHL1 interacted with OPN in a protein complex. The effects of GA activation on inducing UCHL1 and anti-inflammatory macrophage profiles were mediated by OPN. Functional pathway analyses revealed two inversely regulated pathways in OPN-deficient macrophages: activated oxidative stress and lysosome-mitochondria-mediated apoptosis (e.g., ROS, Lamp1-2, ATP-synthase subunits, cathepsins, and cytochrome C and B subunits) and inhibited translation and proteolytic pathways (e.g., 60S and 40S ribosomal subunits and UPS proteins). In agreement with the proteome-bioinformatics data, western blot and immunocytochemical analyses revealed that OPN deficiency perturbs protein homeostasis in macrophages-inhibiting translation and protein turnover and inducing apoptosis-whereas OPN induction by GA restores cellular proteostasis. Taken together, OPN is essential for macrophage homeostatic balance via the regulation of protein synthesis, UCHL1-UPS axis, and mitochondria-mediated apoptotic processes, indicating its potential application in immune-based therapies.

Glioma immunotherapy enhancement and CD8-specific sialic acid cleavage by isocitrate dehydrogenase (IDH)-1.

The promise of adaptive cancer immunotherapy in treating highly malignant tumors such as glioblastoma multiforme (GBM) can only be realized through expanding its benefits to more patients. Alleviating various modes of immune suppression has so far failed to achieve such expansion, but exploiting endogenous immune enhancers among mutated cancer genes could represent a more direct approach to immunotherapy improvement. We found that Isocitrate Dehydrogenase-1 (IDH1), which is commonly mutated in gliomas, enhances glioma vaccine efficacy in mice and discerns long from short survivors after vaccine therapy in GBM patients. Extracellular IDH1 directly enhanced T cell responses to multiple tumor antigens, and prolonged experimental glioma cell lysis. Moreover, IDH1 specifically bound to and exhibited sialidase activity against CD8. By contrast, mutant IDH1R132H lacked sialidase activity, delayed killing in glioma cells, and decreased host survival after immunotherapy. Overall, our findings identify IDH1 as an immunotherapeutic enhancer that mediates the known T cell-enhancing reaction of CD8 desialylation. This uncovers a new axis for immunotherapeutic improvement in GBM and other cancers, reveals novel physiological and molecular functions of IDH1, and hints at an unexpectedly direct link between lytic T cell function and metabolic activity in target cells.

Retinal arterial Aß40 deposition is linked with tight junction loss and cerebral amyloid angiopathy in MCI and AD patients.

INTRODUCTION: Vascular amyloid beta (Aß) protein deposits were detected in retinas of mild cognitively impaired (MCI) and Alzheimer's disease (AD) patients. We tested the hypothesis that the retinal vascular tight junctions (TJs) were compromised and linked to disease status. METHODS: TJ components and Aß expression in capillaries and larger blood vessels were determined in post mortem retinas from 34 MCI or AD patients and 27 cognitively normal controls and correlated with neuropathology. RESULTS: Severe decreases in retinal vascular zonula occludens-1 (ZO-1) and claudin-5 correlating with abundant arteriolar Aß40 deposition were identified in MCI and AD patients. Retinal claudin-5 deficiency was closely associated with cerebral amyloid angiopathy, whereas ZO-1 defects correlated with cerebral pathology and cognitive deficits. DISCUSSION: We uncovered deficiencies in blood-retinal barrier markers for potential retinal imaging targets of AD screening and monitoring. Intense retinal arteriolar Aß40 deposition suggests a common pathogenic mechanism of failed Aß clearance via intramural periarterial drainage.

Retinal pathological features and proteome signatures of Alzheimer's disease.

Alzheimer's disease (AD) pathologies were discovered in the accessible neurosensory retina. However, their exact nature and topographical distribution, particularly in the early stages of functional impairment, and how they relate to disease progression in the brain remain largely unknown. To better understand the pathological features of AD in the retina, we conducted an extensive histopathological and biochemical investigation of postmortem retina and brain tissues from 86 human donors. Quantitative examination of superior and inferior temporal retinas from mild cognitive impairment (MCI) and AD patients compared to those with normal cognition (NC) revealed significant increases in amyloid ß-protein (Aß42) forms and novel intraneuronal Aß oligomers (AßOi), which were closely associated with exacerbated retinal macrogliosis, microgliosis, and tissue atrophy. These pathologies were unevenly distributed across retinal layers and geometrical areas, with the inner layers and peripheral subregions exhibiting most pronounced accumulations in the MCI and AD versus NC retinas. While microgliosis was increased in the retina of these patients, the proportion of microglial cells engaging in Aß uptake was reduced. Female AD patients exhibited higher levels of retinal microgliosis than males. Notably, retinal Aß42, S100 calcium-binding protein B+ macrogliosis, and atrophy correlated with severity of brain Aß pathology, tauopathy, and atrophy, and most retinal pathologies reflected Braak staging. All retinal biomarkers correlated with the cognitive scores, with retinal Aß42, far-peripheral AßOi and microgliosis displaying the strongest correlations. Proteomic analysis of AD retinas revealed activation of specific inflammatory and neurodegenerative processes and inhibition of oxidative phosphorylation/mitochondrial, and photoreceptor-related pathways. This study identifies and maps retinopathy in MCI and AD patients, demonstrating the quantitative relationship with brain pathology and cognition, and may lead to reliable retinal biomarkers for noninvasive retinal screening and monitoring of AD.

The Role of Cellular Immunity and Adaptive Immunity in Pathophysiology of Brain and Spinal Cord Tumors.

Major advances have been made in our understanding of CNS tumors, especially glioma, however, the survival of patients with malignant glioma remains poor. While radiation and chemotherapy have increased overall survival, glioblastoma multiforme (GBM) still has one of the worst 5-year survival rates of all human cancers. Here, in this chapter, the authors review the abrogation of the immune system in the tumor setting, revealing many plausible targets for therapy and the current immunotherapy treatment strategies employed. Notably, glioma has also been characterized as a subset of primary spinal cord tumor and current treatment recommendations are outlined here.

Activated T cell therapy targeting glioblastoma cancer stem cells.

Naïve T cells become effector T cells following stimulation by antigen-loaded dendritic cells (DCs) and sequential cytokine activation. We aimed to develop procedures to efficiently activate T cells with tumor-associated antigens (TAAs) to glioblastoma (GBM) stem cells. To remove antigen presentation outside of the immunosuppressive tumor milieu, three different glioma stem cell (GSC) specific antigen sources to load DCs were compared in their ability to stimulate lymphocytes. An activated T cell (ATC) protocol including cytokine activation and expansion in culture to target GSCs was generated and optimized for a planned phase I clinical trial. We compared three different antigen-loading methods on DCs to effectively activate T cells, which were GBM patient-derived GSC-lysate, acid-eluate of GSCs and synthetic peptides derived from proteins expressed in GSCs. DCs derived from HLA-A2 positive blood sample were loaded with TAAs. Autologous T cells were activated by co-culturing with loaded DCs. Efficiency and cytotoxicity of ATCs were evaluated by targeting TAA-pulsed DCs or T2 cells, GSCs, or autologous PHA-blasts. Characteristics of ATCs were evaluated by Flow Cytometry and ELISpot assay, which showed increased number of ATCs secreting IFN-γ targeting GSCs as compared with non-activated T cells and unloaded target cells. Neither GSC-lysate nor acid-eluate loading showed enhancement in response of ATCs but the synthetic peptide pool showed significantly increased IFN-γ secretion and increased cytotoxicity towards target cells. These results demonstrate that ATCs activated using a TAA synthetic peptide pool efficiently enhance cytotoxicity specifically to target cells including GSC.

ZEB1 loss increases glioma stem cell tumorigenicity and resistance to chemoradiation.

OBJECTIVE: Glioblastoma has been known to be resistant to chemotherapy and radiation, whereas the underlying mechanisms of resistance have not been fully elucidated. The authors studied the role of the transcription factor ZEB1 (zinc finger E-box-binding homeobox 1 protein), which is associated with epithelial-mesenchymal transition (EMT) and is central to the stemness of glioblastoma, to determine its role in therapeutic resistance to radiation and chemotherapy. The authors previously demonstrated that ZEB1 is deleted in a majority of glioblastomas. METHODS: The authors explored resistance to therapy in the context of ZEB1 loss and overexpression in glioma stem cells (GSCs) and in patient data. RESULTS: Patients with ZEB1 loss had a shorter survival time than patients with wild-type ZEB1 in both the high- and low-MGMT groups. Consistent with the clinical data, mice implanted with ZEB1 knockdown GSCs showed shortened survival compared with mice inoculated with nonsilencing control (NS) short-hairpin RNA (shRNA) GSC glioblastoma. ZEB1-deleted GSCs demonstrated increased tumorigenicity with regard to proliferation and invasion. Importantly, GSCs that lose ZEB1 expression develop enhanced resistance to chemotherapy, radiotherapy, and combined chemoradiation. ZEB1 loss may lead to increased HER3 expression through the HER3/Akt pathway associated with this chemoresistance. Conversely, overexpression of ZEB1 in GSCs that are ZEB1 null leads to increased sensitivity to chemoradiation. CONCLUSIONS: The study results indicate that ZEB1 loss in cancer stem cells confers resistance to chemoradiation and uncovers a potentially targetable cell surface receptor in these resistant cells.

Regulating microglial miR-155 transcriptional phenotype alleviates Alzheimer's-induced retinal vasculopathy by limiting Clec7a/Galectin-3+ neurodegenerative microglia.

Single cell RNA sequencing studies identified novel neurodegeneration-associated microglial (MGnD/DAM) subtypes activated around cerebral amyloid plaques. Micro-RNA (miR)-155 of the TREM2-APOE pathway was shown to be a key transcriptional regulator of MGnD microglial phenotype. Despite growing interest in studying manifestations of Alzheimer's disease (AD) in the retina, a CNS organ accessible to noninvasive high-resolution imaging, to date MGnD microglia have not been studied in the AD retina. Here, we discovered the presence and increased populations of Clec7a+ and Galectin-3+ MGnD microglia in retinas of transgenic APPSWE/PS1L166P AD-model mice. Conditionally targeting MGnD microglia by miR-155 ablation via the tamoxifen-inducible CreERT2 system in APPSWE/PS1L166P mice diminished retinal Clec7a+ and Galectin-3+ microglial populations while increasing homeostatic P2ry12+ microglia. Retinal MGnD microglia were often adhering to microvessels; their depletion protected the inner blood-retina barrier and reduced vascular amyloidosis. Microglial miR-155 depletion further limits retinal inflammation. Mass spectrometry analysis revealed enhanced retinal PI3K-Akt signaling and predicted IL-8 and Spp1 decreases in mice with microglia-specific miR-155 knockout. Overall, this study identified MGnD microglia in APPSWE/PS1L166P mouse retina. Transcriptional regulation of these dysfunctional microglia mitigated retinal inflammation and vasculopathy. The protective effects of microglial miR-155 ablation should shed light on potential treatments for retinal inflammation and vascular damage during AD and other ocular diseases.

Label-free hyperspectral imaging and deep-learning prediction of retinal amyloid ß-protein and phosphorylated tau.

Alzheimer's disease (AD) is a major risk for the aging population. The pathological hallmarks of AD-an abnormal deposition of amyloid ß-protein (Aß) and phosphorylated tau (pTau)-have been demonstrated in the retinas of AD patients, including in prodromal patients with mild cognitive impairment (MCI). Aß pathology, especially the accumulation of the amyloidogenic 42-residue long alloform (Aß42), is considered an early and specific sign of AD, and together with tauopathy, confirms AD diagnosis. To visualize retinal Aß and pTau, state-of-the-art methods use fluorescence. However, administering contrast agents complicates the imaging procedure. To address this problem from fundamentals, ex-vivo studies were performed to develop a label-free hyperspectral imaging method to detect the spectral signatures of Aß42 and pS396-Tau, and predicted their abundance in retinal cross-sections. For the first time, we reported the spectral signature of pTau and demonstrated an accurate prediction of Aß and pTau distribution powered by deep learning. We expect our finding will lay the groundwork for label-free detection of AD.

Signature Effects of Vector-Guided Systemic Nano Bioconjugate Delivery Across Blood-Brain Barrier of Normal, Alzheimer's, and Tumor Mouse Models.

The ability to cross the blood-brain barrier (BBB) is critical for targeted therapy of the central nerve system (CNS). Six peptide vectors were covalently attached to a 50 kDa poly(ß-l-malic acid)-trileucine polymer forming P/LLL(40%)/vector conjugates. The vectors were Angiopep-2 (AP2), B6, Miniap-4 (M4), and d-configurated peptides D1, D3, and ACI-89, with specificity for transcytosis receptors low-density lipoprotein receptor-related protein-1 (LRP-1), transferrin receptor (TfR), bee venom-derived ion channel, and Aß/LRP-1 related transcytosis complex, respectively. The BBB-permeation efficacies were substantially increased ("boosted") in vector conjugates of P/LLL(40%). We have found that the copolymer group binds at the endothelial membrane and, by an allosterically membrane rearrangement, exposes the sites for vector-receptor complex formation. The specificity of vectors is indicated by competition experiments with nonconjugated vectors. P/LLL(40%) does not function as an inhibitor, suggesting that the copolymer binding site is eliminated after binding of the vector-nanoconjugate. The two-step mechanism, binding to endothelial membrane and allosteric exposure of transcytosis receptors, is supposed to be an integral feature of nanoconjugate-transcytosis pathways. In vivo brain delivery signatures of the nanoconjugates were recapitulated in mouse brains of normal, tumor (glioblastoma), and Alzheimer's disease (AD) models. BBB permeation of the tumor was most efficient, followed by normal and then AD-like brain. In tumor-bearing and normal brains, AP2 was the top performing vector; however, in AD models, D3 and D1 peptides were superior ones. The TfR vector B6 was equally efficient in normal and AD-model brains. Cross-permeation efficacies are manifested through modulated vector coligation and dosage escalation such as supra-linear dose dependence and crossover transcytosis activities.

Glatiramer Acetate Immunomodulation: Evidence of Neuroprotection and Cognitive Preservation.

Novel, neuroprotective uses of Copaxone (generic name: glatiramer acetate-GA) are being examined, primarily in neurological conditions involving cognitive decline. GA is a well-studied synthetic copolymer that is FDA-approved for immune-based treatment of relapsing remitting multiple sclerosis (RRMS). Clinical studies have explored the potential mechanism of action (MOA) and outcomes of GA immunization in patients. Furthermore, results from these and animal studies suggest that GA has a direct immunomodulatory effect on adaptive and innate immune cell phenotypes and responses. These MOAs have been postulated to have a common neuroprotective impact in several neuroinflammatory and neurodegenerative diseases. Notably, several clinical studies report that the use of GA mitigated MS-associated cognitive decline. Its propensity to ameliorate neuro-proinflammatory and degenerative processes ignites increased interest in potential alternate uses such as in age-related macular degeneration (AMD), amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (AD). Preclinical studies are exploring less frequent subcutaneous administration of GA, such as once weekly or monthly or a single dosing regimen. Indeed, cognitive functions were found to be either preserved, reversed, or improved after the less frequent treatment regimens with GA in animal models of AD. In this systematic review, we examine the potential novel uses of GA across clinical and pre-clinical studies, with evidence for its beneficial impact on cognition. Future investigation in large-size, double-blind clinical trials is warranted to establish the impact of GA immunomodulation on neuroprotection and cognitive preservation in various neurological conditions.

A Phase I Study of Autologous Dendritic Cell Vaccine Pulsed with Allogeneic Stem-like Cell Line Lysate in Patients with Newly Diagnosed or Recurrent Glioblastoma.

PURPOSE: Glioblastoma (GBM) is a heterogeneous malignancy with multiple subpopulations of cancer cells present within any tumor. We present the results of a phase I clinical trial using an autologous dendritic cell (DC) vaccine pulsed with lysate derived from a GBM stem-like cell line. PATIENTS AND METHODS: Patients with newly diagnosed and recurrent GBM were enrolled as separate cohorts. Eligibility criteria included a qualifying surgical resection or minimal tumor size, ≤ 4-mg dexamethasone daily dose, and Karnofsky score ≥70. Vaccine treatment consisted of two phases: an induction phase with vaccine given weekly for 4 weeks, and a maintenance phase with vaccines administered every 8 weeks until depletion of supply or disease progression. Patients with newly diagnosed GBM also received standard-of-care radiation and temozolomide. The primary objective for this open-label, single-institution trial was to assess the safety and tolerability of the autologous DC vaccine. RESULTS: For the 11 patients with newly diagnosed GBM, median progression-free survival (PFS) was 8.75 months, and median overall survival was 20.36 months. For the 25 patients with recurrent GBM, median PFS was 3.23 months, 6-month PFS was 24%, and median survival was 11.97 months. A subset of patients developed a cytotoxic T-cell response as determined by an IFNγ ELISpot assay. CONCLUSIONS: In this trial, treatment of newly diagnosed and recurrent GBM with autologous DC vaccine pulsed with lysate derived from an allogeneic stem-like cell line was safe and well tolerated. Clinical outcomes add to the body of evidence suggesting that immunotherapy plays a role in the treatment of GBM.