Biology subjects

Naaldijk, Y.

Publications and source records attributed to Naaldijk, Y..

6 recordsLinked to original sources

bioRxiv2025

Leucine-rich repeat kinase 2 impairs the release sites of Parkinson's disease vulnerable dopamine axons

The end-stage pathology of Parkinsons disease (PD) involves the loss of dopamine-producing neurons in the substantia nigra pars compacta (SNc). However, synaptic deregulation of these neurons begins much earlier. Understanding the mechanisms behind synaptic deficits is crucial for early therapeutic intervention, yet these remain largely unknown. In the SNc, different dopamine neuron subtypes show varying susceptibility patterns to PD, complicating our understanding. This study uses intersectional genetic mouse models to uncover synaptic perturbations in vulnerable dopamine neurons, focusing on the LRRK2 kinase, a protein closely linked to PD. Through a combination of immunofluorescence and advanced proximity labeling methods, we found higher LRRK2 expression in the most vulnerable dopamine neuron subclusters. High-resolution imaging revealed that pathogenic LRRK2 disrupts release sites in vulnerable dopamine axons, leading to decreased in vivo spontaneous and evoked striatal dopamine release in mice with LRRK2 mutations. Proteomic and biochemical analyses indicate that mutant LRRK2 increases the phosphorylation of RAB3 proteins, reducing their interactions with RIM1and RIM2 effector proteins and impacting their synaptic functions. Overall, this research highlights the cell-autonomous dysfunctions caused by mutant LRRK2 in neurons, which are primarily affected by the disease. It also provides a framework for future therapeutic strategies for early nigrostriatal synaptic deficits in PD.

neuroscience↗

bioRxiv2024

Pathogenic LRRK2 causes age-dependent and region-specific deficits in ciliation, innervation and viability of cholinergic neurons

Pathogenic activating point mutations in the LRRK2 kinase cause autosomal-dominant familial Parkinso[n]s disease (PD). In cultured cells, mutant LRRK2 causes a deficit in de novo cilia formation and also impairs ciliary stability. In brain, previous studies have shown that in PD patients due to the G2019S-LRRK2 mutation as well as in middle-aged G2019S-LRRK2 knockin mice, striatal cholinergic interneurons show a deficit in primary cilia. Here, we show that cilia loss in G2019S-LRRK2 knockin mice is not limited to cholinergic striatal interneurons but common to cholinergic neurons across distinct brain nuclei. The lack of cilia in cholinergic forebrain neurons is accompanied by the accumulation of LRRK2-phosphorylated Rab12 GTPase and correlates with the presence of dystrophic cholinergic axons. Those deficits are already evident in young adult mutant LRRK2 mice. In contrast, the age-dependent loss of cilia in brainstem cholinergic neurons correlates with an age-dependent loss of cholinergic innervation derived from this brain area. Strikingly, we find cholinergic cell loss in mutant LRRK2 mice that is age-dependent, cell type-specific and disease-relevant. The age-dependent loss of a subset of cholinergic neurons mimics that observed in sporadic PD patients, highlighting the possibility that these particular neurons may require functional cilia for long-term cell survival.

neuroscience↗

bioRxiv2023

Targeting phosphoRab-RILPL Interactions as a Strategy to Downregulate Pathogenic LRRK2 in Parkinson's Disease

Familial Parkinsons disease (PD) is frequently linked to multiple disease-causing mutations within Leucine-Rich Repeat Protein Kinase 2 (LRRK2), leading to aberrant kinase activity. Multiple pathogenic effects of enhanced LRRK2 activity have been identified including loss of cilia and centrosomal cohesion defects. When phosphorylated by LRRK2, Rab8a and Rab10 bind to phospho-specific RILPL effector proteins. RILPL-mediated accumulation of pRabs proximal to the mother centriole is critical for initiating deficits in ciliogenesis and centrosome cohesion mediated by LRRK2. We hypothesized that Rab-derived phospho-mimics may serve to block phosphorylated Rab proteins from docking with RILPL in the context of hyperactive LRRK2 mutants. This would serve as an alternative strategy to downregulate pathogenic signaling mediated by LRRK2, rather than targeting LRRK2 kinase activity itself. To test this theory, we designed a series of constrained peptides mimicking phosphorylated Switch II derived from Rab8. These RILPL interacting peptides, termed RIP, were further shown to permeate cells. Further, several peptides were found to bind RILPL2 and restore ciliogenesis and centrosomal cohesion defects in cells expressing PD-associated mutant LRRK2. This research demonstrates the utility of constrained peptides as downstream inhibitors to target pathogenic LRRK2 activity and may provide an alternative approach to target specific pathways activated by LRRK2.

biochemistry↗

bioRxiv2023

A potential patient stratification biomarker for Parkinson's disease based on LRRK2 kinase-mediated centrosomal alterations in peripheral blood-derived cells

Parkinsos disease (PD) is a common neurodegenerative movement disorder and leucine-rich repeat kinase 2 (LRRK2) is a promising therapeutic target for disease intervention. However, the ability to stratify patients who will benefit from such treatment modalities based on shared etiology is critical for the success of disease-modifying therapies. Ciliary and centrosomal alterations are commonly associated with pathogenic LRRK2 kinase activity and can be detected in many cell types. We previously found centrosomal deficits in immortalized lymphocytes from G2019S-LRRK2 PD patients. Here, to investigate whether such deficits may serve as a potential blood biomarker for PD which is susceptible to LRKK2 inhibitor treatment, we characterized patient-derived cells from distinct PD cohorts. We report centrosomal alterations in peripheral cells from a subset of early-stage idiopathic PD patients which is mitigated by LRRK2 kinase inhibition, supporting a role for aberrant LRRK2 activity in idiopathic PD. Centrosomal defects are detected in R1441G-LRRK2 and G2019S-LRRK2 PD patients and in non-manifesting LRRK2 mutation carriers, indicating that they acumulate prior to a clinical PD diagnosis. They are present in immortalized cells as well as in primary lymphocytes from peripheral blood. These findings indicate that analysis of centrosomal defects as a blood-based patient stratification biomarker may help nominate PD patients who will benefit from LRRK2-related therapeutics. One-sentence summaryPeripheral blood-derived cells can be employed to stratify Parkinsos disease patients most likely to respond to LRRK2-related therapeutics.

neuroscience↗

bioRxiv2022

Bone Marrow- and Umbilical Cord-Derived Mesenchymal Stem Cell Secretome Alters Gene Expression and Upregulates Motility of Human Endometrial Stromal Cells

IntroductionCyclic regeneration of the endometrium, and its repair after parturition or injury, are crucial for successful reproduction. Mesenchymal stem cells (MSCs) derived from bone marrow (BM-MSC) and umbilical cord (UC-MSC) facilitate tissue repair via their secretome, which contains growth factors and cytokines that promote wound healing. Despite the implication of MSCs in endometrial regeneration and repair, the mechanisms remain unclear. This study tested the hypothesis that the secretome of MSCs from human BM and UC upregulates human endometrial stromal cell (HESC) proliferation, migration and invasion, and activates pathways to increase HESC motility. MethodsMSCs were purchased from ATCC (BM-MSC-1) and cultured from the BM aspirate of three healthy female donors (BM-MSC-2-4), and from umbilical cords of two healthy male term infants (UC-MSC-1-2). Indirect co-culture of MSCs and hTERT-immortalized HESCs via a transwell system studied the effect of the BM-MSC and UC-MSC secretome on HESC proliferation, migration, and invasion. To study the effect of the MSC secretome on HESC gene expression, HESCs were exposed to the BM-MSC secretome via indirect co-culture for 24 h. Total RNA was extracted from HESCs for RNA sequencing (RNA-Seq). Differentially expressed genes (DEG) and significantly altered pathways were identified. MSigDB was used to identify the top 15 enriched biological pathways (padj < 0.05). RT-qPCR was performed to validate changes in mRNA expression of DEG common to both BM-MSC exposures. Given robust upregulation of CCL2 mRNA expression in HESCs exposed to the BM- and UC-MSC secretomes, transwell migration and invasion assays were performed to determine the effect of recombinant CCL2 on HESC motility. Statistical significance was defined as p<0.05. ResultsIndirect co-culture of HESCs with BM- or UC-MSCs resulted in significant increase in HESC migration and invasion regardless of the source of MSCs. However, effects on cellular proliferation varied among the MSC donors. Exposure of HESCs to the secretome of BM-MSCs changed the expression of 10,139 genes with FDR < 0.05. There was overlap among 4350 genes between HESCs exposed to BM-MSC-1 and BM-MSC-2. Within four biological pathways enriched in HESCs, 4 genes (CCL2, HGF, PLAU, and BDKRB2) were differentially expressed in HESCs that had been cocultured with BM-MSC-1 and BM-MSC-2. qRT-PCR showed significantly increased mRNA expression of CCL2 in HESCs exposed to BM-MSC-1 (5-fold) and BM-MSC-2 (7.7-fold). In contrast, the increase in HGF expression was significant after exposure to BM-MSC-2 (1.8-fold) but not BM-MSC-1. Exposure to the UC-MSC secretome had similar effects on HESC-derived CCL2 and HGF levels. CCL2 expression was significantly increased (6.5-fold) by UC-MSC-2 but not by UC-MSC-1; HGF expression was significantly increased (1.6-fold) by UC-MSC-2 but not by UC-MSC-1. Validation studies indicated that exposure to recombinant CCL2 for 48 hours significantly increased HESC migration (1.2-fold) and invasion (1.4-fold). These data suggest that CCL2 is a key factor in mediating MSC-induced HESC motility. ConclusionIncreased HESC motility by the secretome of BM- and UC-MSC appears to be mediated by paracrine and autocrine mechanisms, in part by upregulated CCL2 expression in HESC. Together, our data support the potential for leveraging the MSC secretome as a novel cell-free therapy in the treatment of disorders of endometrial regeneration.

cell biology↗

bioRxiv2021

LRRK2 causes centrosomal deficits via phosphorylated Rab10 and RILPL1 at centriolar subdistal appendages

The Parkinsons disease-associated LRRK2 kinase phosphorylates multiple Rab GTPases including Rab8 and Rab10, which enhances their binding to RILPL1 and RILPL2. The nascent interaction between phospho-Rab10 and RILPL1 blocks ciliogenesis in vitro and in the intact brain, and interferes with the cohesion of duplicated centrosomes in dividing cells. We show here that various LRRK2 risk variants and all currently described regulators of the LRRK2 signaling pathway converge upon causing centrosomal cohesion deficits. The cohesion deficits do not require the presence of RILPL2 or of other LRRK2 kinase substrates including Rab12, Rab35 and Rab43. Rather, they depend on the RILPL1-mediated centrosomal accumulation of phosphorylated Rab10. RILPL1 localizes to the subdistal appendages of the mother centriole, followed by recruitment of the LRRK2-phosphorylated Rab protein to cause the centrosomal defects. These data reveal a common molecular pathway by which alterations in the LRRK2 kinase activity impact upon centrosome-related events.

neuroscience↗