Biology subjects

Manfredsson, F. P.

Publications and source records attributed to Manfredsson, F. P..

5 recordsLinked to original sources

bioRxiv2026

Dual kinase inhibition provides early clues to restoration of neuroimmune homeostasis in an AAV-haSyn model of Parkinsons disease

Background Previous studies of drugs targeting mixed linage kinase type 3 (MLK3) and/or leucine rich repeat kinase type 2 (LRRK2) in sporadic Parkinsons disease (PD) have failed to meet clinical endpoints despite multiple lines of evidence implicating these kinases in pathogenesis. This has reduced enthusiasm for MLK3 and LRRK2 as druggable targets. Largely overlooked is the evidence that these targets remain valid but must be considered in combination to achieve a therapeutic outcome. This provides the rationale for this study. Methods We conducted a pilot study modeling early, pre-symptomatic PD with subsequent evaluation of therapeutic potential of a multi-kinase inhibitor (URMC-099) in alleviating disease pathology. Sprague Dawley rats received unilateral intranigral injections of low dose AAV-haSyn. After a two-week recovery period, all animals were administered either once-daily intraperitoneal (i.p.) injection of URMC-099 or its vehicle control until their terminal endpoint. Induction of early PD, and its alleviation with URMC-099, was evaluated by lateralized motor impairment using the cylinder test and immunohistochemical analysis of neuropathology in the substantia nigra (SN) and striatum. Finally, an in vitro microglial PD model exposed to aSyn pre-formed fibrils and treated with URMC-099 was used to further evaluate the mechanism underlying therapeutic activity. Results A unilateral model of early and progressive AAV-haSyn model for PD was used to demonstrate the therapeutic potential of a targeted multi-kinase inhibitor to attenuate PD-associated neuropathology and prevent the manifestation of lateral motor deficits. Immunohistochemical analysis revealed protection of neuronal cellular integrity along the nigral-striatal pathway with once-daily i.p. URMC-099. The mitigation of degenerative neuropathology was linked to targeted inhibition of MLK3 and LRRK2 and complemented by reduced levels of gliosis in astrocytes and microglia in the SN. Single-microglia segmentation analysis suggested URMC-099 treatment preserved dynamic effector state switching in microglia to enhance autophagic flux to reduce the overall burden of pathologic aSyn. Transcriptomic analysis of a complementary in vitro microglia model corroborated the retention of a homeostatic-like effector state with URMC-099 treatment that was unique to MLK3/LRRK2 dual inhibition. Conclusions Unilateral injection of low dose AAV-haSyn successfully resulted in a lateralized model of early, progressive PD. Dual inhibition of aberrant MLK3 and LRRK2 activity with once-daily i.p. URMC-099 therapy significantly mitigated the development of PD pathology and progression in an early manifest phenotype. Our results present a potential mechanism of therapeutic action dependent on the dual inhibition of MLK3 and LRRK2. This presents a novel therapeutic modality that may be beneficial to a broad population of etiologic PD patients.

neuroscience↗

bioRxiv2024

Amyloid-beta, alpha-synuclein and tau aggregated co-pathologies enhance neuropathology and neuroinflammation

Alzheimers (AD) and Parkinson disease (PD) pathology often co-occur. Amyloid-{beta} and phosphorylated tau are found in 30-50% of idiopathic PD cases, while -synuclein inclusions are present in 50% of AD cases. These co-pathologies are linked to increased mortality and earlier onset of cognitive decline. Immune activation is a hallmark of these neurodegenerative diseases, but current models primarily examine each pathology in isolation. How these co-pathologies drive inflammation and neuronal loss remains poorly understood. We therefore developed a mouse model combining tau, amyloid-{beta}, and -synuclein. We found that co-pathologies synergistically trigger an amplified neuroimmune response, with expanded populations of CD4+ and CD8+ tissue-resident memory T cells and CD68+ microglia, compared to single pathologies. These changes were abundant in the hippocampus and cortex, regions with elevated protein pathology load and enhanced neuronal loss. Our findings demonstrate that co-pathologies enhance proteinopathy and synergistically enhance immune activation and neurodegeneration, suggesting that combinatorial therapeutic strategies that target both co-pathologies and inflammation, may be disease modifying. SummaryWebster et al. demonstrate that co-occurring Alzheimers and Parkinson disease protein pathologies, common in cognitively impaired patient populations, amplify proteinopathy and synergistically enhance CNS neuroinflammatory responses and neurodegeneration. This work supports the need for combinatorial therapeutic strategies and positions neuroinflammation as an important link for co-pathology enhanced neurodegeneration.

neuroscience↗

bioRxiv2023

Modulation of cannabinoid receptor 2 alters neuroinflammation and reduces formation of alpha-synuclein aggregates in a rat model of nigral synucleinopathy

Research into the disequilibrium of microglial phenotypes has become an area of intense focus in neurodegenerative disease as a potential mechanism that contributes to chronic neuroinflammation and neuronal loss in Parkinsons disease (PD). There is growing evidence that neuroinflammation accompanies and may promote progression of alpha-synuclein (Asyn)-induced nigral dopaminergic (DA) degeneration. From a therapeutic perspective, development of immunomodulatory strategies that dampen overproduction of pro-inflammatory cytokines from chronically activated immune cells and induce a pro-phagocytic phenotype is expected to promote Asyn removal and protect vulnerable neurons. Cannabinoid receptor-2 (CB2) is highly expressed on activated microglia and peripheral immune cells, is upregulated in the substantia nigra of individuals with PD and in mouse models of nigral degeneration. Furthermore, modulation of CB2 protects against rotenone-induced nigral degeneration; however, CB2 has not been pharmacologically and selectively targeted in an Asyn model of PD. Here, we report that 7 weeks of peripheral administration of CB2 inverse agonist SMM-189 reduced phosphorylated (pSer129) alpha-synuclein in the substantia nigra compared to vehicle treatment. Additionally, SMM-189 delayed Asyn-induced immune cell infiltration into the brain as determined by flow cytometry, increased CD68 protein expression, and elevated wound-healing-immune-mediator gene expression. Additionally, peripheral immune cells increased wound-healing non-classical monocytes and decreased pro-inflammatory classical monocytes. In vitro analysis of RAW264.7 macrophages treated with lipopolysaccharide (LPS) and SMM-189 revealed increased phagocytosis as measured by the uptake of fluorescence of pHrodo E. coli bioparticles. Together, results suggest that targeting CB2 with SMM-189 skews immune cell function toward a phagocytic phenotype and reduces toxic aggregated species of Asyn. Our novel findings demonstrate that CB2 may be a target to modulate inflammatory and immune responses in proteinopathies.

immunology↗

bioRxiv2019

α-synuclein aggregates induce c-Abl activation and neurodegeneration by a redox stress mechanism

ObjectiveRedox stress, c-Abl activation, and -synuclein aggregates each independently contribute to neurodegeneration in Parkinsons disease. Interactions between these factors may underlie convergent and feed-forward mechanisms of disease progression. Methods-synuclein aggregate formation was induced in neuronal cultures and mouse substantia nigra by exposure to pre-formed human -synuclein fibrils or by AAV-mediated over-expression of -synuclein. Aggregate formation, c-Abl activation, redox stress, and neurodegeneration were evaluated by immunohistochemistry and Western blots, and mouse motor function was evaluated using the rota-rod and pole tests. To suppress redox stress, cultures and mice were treated with N-acetyl cysteine, a thiol repletion agent that supports neuronal glutathione metabolism. ResultsIn primary neuron cultures, the formation of -synuclein aggregates led to redox stress and c-Abl activation. Redox stress alone, in the absence of -synuclein aggregates, was also sufficient to induced c-Abl activation. N-acetyl cysteine suppressed redox stress, and likewise suppressed both c-Abl activation and -synuclein aggregation. A similar pattern was observed in the two mouse models of Parkinsons disease. In both models, -synuclein aggregates in the substantia nigra were accompanied by redox stress, c-Abl activation, dopaminergic neurodegeneration and motor impairment, all of which were attenuated in mice treated with oral N-acetyl cysteine. InterpretationThese results indicate that -synuclein aggregates induce c-Abl activation by a redox stress mechanism. c-Abl in turn promotes -synuclein aggregation, and this potentially feed-forward process can be blocked by N-acetyl cysteine. The findings thus add mechanistic support for N-acetyl cysteine as a therapeutic for Parkinsons disease.

neuroscience↗

bioRxiv2019

The Norepinephrine Metabolite DOPEGAL Confers Locus Coeruleus Tau Vulnerability and Propagation via Asparagine Endopeptidase

Aberrant Tau inclusions in the locus coeruleus (LC) are the earliest detectable Alzheimers disease (AD)-like neuropathology in the human brain; however, why LC neurons are selectively vulnerable to developing early Tau pathology and degenerating later in disease and whether the LC might seed the stereotypical spread of Tau pathology to the rest of the brain remain unclear. Here we show that 3,4-dihydroxyphenylglycolaldehyde (DOPEGAL), which is produced exclusively in noradrenergic neurons by monoamine oxidase A (MAO-A) metabolism of norepinephrine (NE), activates asparagine endopeptidase (AEP) that cleaves Tau at residue N368 into aggregation- and propagation-prone forms, thereby leading to LC degeneration and the spread of Tau pathology. DOPEGAL triggers AEP-cleaved Tau aggregation in vitro and in intact cells, resulting in LC neurotoxicity and propagation of pathology to the forebrain. Thus, our findings reveal a novel molecular mechanism underlying the selective vulnerability of LC neurons in AD.

neuroscience↗