Open Access
Olfactory characterization and training in older adults: protocol study
(Frontiers Media, 2021) Zambom Ferraresi, Fabíola; Zambom Ferraresi, Fabrício; Fernández Irigoyen, Joaquín; Lachén Montes, Mercedes; Cartas Cejudo, Paz; Lasarte, Juan José; Casares, Noelia; Fernández, Secundino; Cedeño Veloz, Bernardo Abel; Maravi Aznar, Enrique; Uzcanga Lacabe, María Iciar; Galbete Jiménez, Arkaitz; Santamaría Martínez, Enrique; Martínez Velilla, Nicolás; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Gobierno de Navarra / Nafarroako Gobernua
The aim of this article is to present the research protocol for a prospective cohort study that will assess the olfactory function and the effect of an intervention based on olfactory training in healthy very old adults (≥75 years old). A convenience sample of 180 older people (50% female) will be recruited in three different environments: hospitalized control group (CH) with stable acute illness (n = 60); ambulatory control group (CA) of community-based living (n = 60); and an experimental odor training group (EOT) from nursing homes (n = 60). The odor training (OT) intervention will last 12 weeks. All the volunteers will be assessed at baseline; CA and EOT groups will also be assessed after 12 weeks. The primary end point will be change in olfactory capacity from baseline to 12 weeks period of intervention or control. The intervention effects will be assessed with the overall score achieved in Sniffin Sticks Test (SST) – Threshold, Discrimination, and Identification (TDI) extended version. Secondary end points will be changes in cognitive tasks, quality of life, mood, immune status, and functional capacity. All these measurements will be complemented with an immune fitness characterization and a deep proteome profiling of the olfactory epithelium (OE) cultured ex vivo. The current study will provide additional evidence to support the implementation of olfactory precision medicine and the development of immunomodulatory nasal therapies based on non-invasive procedures. The proposed intervention will also intend to increase the knowledge about the olfactory function in very elderly people, improve function and quality of life, and promote the recovery of the health.
Open Access
Smelling the dark proteome: functional characterization of PITH domain-containing protein 1 (C1orf128) in olfactory metabolism
(American Chemical Society, 2020) Lachén Montes, Mercedes; Mendizuri, Naroa; Ausín, Karina; Pérez Mediavilla, Alberto; Azkargorta, Mikel; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Iloro, Ibon; Elortza, Félix; Kondo, Hiroyuki; Ohigashi, Izumi; Ferrer, Isidro; Torre, Rafael de la; Robledo, Patricia; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The Human Proteome Project (HPP) consortium aims to functionally characterize the dark proteome. On the basis of the relevance of olfaction in early neurodegeneration, we have analyzed the dark proteome using data mining in public resources and omics data sets derived from the human olfactory system. Multiple dark proteins localize at synaptic terminals and may be involved in amyloidopathies such as Alzheimer's disease (AD). We have characterized the dark PITH domain-containing protein 1 (PITHD1) in olfactory metabolism using bioinformatics, proteomics, in vitro and in vivo studies, and neuropathology. PITHD1-/- mice exhibit olfactory bulb (OB) proteome changes related to synaptic transmission, cognition, and memory. OB PITHD1 expression increases with age in wild-type (WT) mice and decreases in Tg2576 AD mice at late stages. The analysis across 6 neurological disorders reveals that olfactory tract (OT) PITHD1 is specifically upregulated in human AD. Stimulation of olfactory neuroepithelial (ON) cells with PITHD1 alters the ON phosphoproteome, modifies the proliferation rate, and induces a pro-inflammatory phenotype. This workflow applied by the Spanish C-HPP and Human Brain Proteome Project (HBPP) teams across the ON-OB-OT axis can be adapted as a guidance to decipher functional features of dark proteins. Data are available via ProteomeXchange with identifiers PXD018784 and PXD021634.
Open Access
Impact of medication use on olfactory performance in older adults
(Frontiers Media, 2025-04-03) Izco-Cubero, Maite; Zambom Ferraresi, Fabíola; Zambom Ferraresi, Fabrício; Fernández González de la Riva, María Luisa; Santamaría Martínez, Enrique; Fernández Irigoyen, Joaquín; Lachén Montes, Mercedes; Lasarte, Juan José; Uzcanga Lacabe, María Iciar; Fernández, Secundino; Sanjurjo San Martín, Gloria; Maravi Aznar, Enrique; Martínez Velilla, Nicolás; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Introduction: Olfactory dysfunction impacts quality of life, safety, and nutrition. Despite its relevance among older adults, the role of medications in influencing olfactory performance remains understudied. This research investigates whether olfactory alterations in older adults are associated with the type or number of medications prescribed. Methods: An observational cross-sectional study was conducted with 107 participants (mean age of 86.1 ± 5.1 years). Olfactory performance was evaluated using the Sniffin’ Sticks Test (SST). Functional capacity, cognitive function and the number and type of medications were also assessed. Results: The analysis demonstrated a correlation between better olfactory performance and higher cognitive function. An inverse correlation was found between the age of participants and olfactory identification. While polypharmacy (intake of five or more medications) did not show a significant association with olfactory dysfunction, the intake of laxatives was associated with poorer olfactory threshold performance (−1.21, 95% CI −2.07 to −0.34; p = 0.008). In contrast, proton pump inhibitors (PPIs) (1.14, 95% CI 0.07 to 2.21; p = 0.04) and vitamin D (1.09, 95% CI 0.03 to 2.15; p = 0.04) intake were linked to improved olfactory identification. Discussion: These findings suggest that certainmedications influence olfactory performance; however, further research is needed to clarify the effects of different drug classes on olfaction.
Open Access
Olfaction and neurodegeneration: olfactory proteotyping across proteinopathies
(2019) Lachén Montes, Mercedes; Santamaría Martínez, Enrique; Fernández Irigoyen, Joaquín; Ciencias de la Salud; Osasun Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua
La disfunción olfatoria es un síntoma temprano y común en diversas enfermedades neurodegenerativas (ENs). Según el grado de disfunción olfatoria que presentan, existen ENs con disfunción olfatoria pronunciada, como la enfermedad de Alzheimer (EA) y la enfermedad de Parkinson (EP), y otras con déficits más leves, como ocurre en las demencias frontotemporales. Se ha sugerido que la existencia de un sustrato patológico común actuando mediante diferentes mecanismos en este amplio espectro de ENs podría ser el causante de estas diferencias en el déficit olfatorio. El bulbo olfatorio (BO) es la primera estructura del cerebro responsable de procesar la información olfatoria y el depósito de sustratos neuropatológicos como el péptido amiloide o la forma hiperfosforilada de la proteína tau en esta región se ha propuesto también como posible origen de este síntoma. Sin embargo, se desconoce si los agregados neuropatológicos son causa o consecuencia del proceso neurodegenerativo que ocurre en esta región. En esta tesis se ha realizado un análisis molecular de alto rendimiento en BOs procedentes de: a) dos modelos animales de la EA; y b) sujetos diagnosticados con cuatro ENs incluyendo la EA, la EP, la degeneración lobar fronto-temporal con depósitos de TAR DNA-binding protein (FTLD-TDP43) y la parálisis supranuclear progresiva (PSP), con el objetivo de caracterizar los mecanismos neuropatofisiológicos que ocurren en esta región durante el proceso neurodegenerativo. Este amplio análisis ha demostrado que existe una gran alteración en la proteostasis del BO durante la EA y la EP, donde los resultados mostraron un 20% del proteoma cuantificado diferencialmente expresado. Por otra parte, en el caso de los sujetos diagnosticados con FTLD-TDP43 y PSP, el número de alteraciones fue mucho menor, constituyendo alrededor del 1% del proteoma cuantificado. Es interesante resaltar que se han encontrado tanto similitudes como diferencias en los mediadores proteicos diferencialmente expresados entre las ENs analizadas y la población control. Por otra parte, el estudio en los dos modelos animales de EA ha demostrado que, a nivel de BO, existen alteraciones moleculares previas a la aparición de placas amiloides y deficits cognitivos. Finalmente, se ha demostrado la utilidad de la proteómica dirigida a estructuras olfatorias como fuente de biomarcadores en ENs. De hecho, se propone la proteína Glucosamine-6-phosphate isomerase 2 (GNPDA2) como potencial biomarcador de la EP.
Open Access
Progressive modulation of the human olfactory bulb transcriptome during Alzheimer´s disease evolution: novel insights into the olfactory signaling across proteinopathies
(Impact Journals, 2017) Lachén Montes, Mercedes; Zelaya Huerta, María Victoria; Segura, Víctor; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua, PC025; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Alzheimer´s disease (AD) is characterized by progressive dementia, initially presenting olfactory dysfunction. Despite the olfactory bulb (OB) is the first central structure of the olfactory pathway, we lack a complete molecular characterization of the transcriptional events that occurs in this olfactory area during AD progression. To address this gap in knowledge, we have assessed the genome-wide expression in postmortem OBs from subjects with varying degree of AD pathology. A stagedependent deregulation of specific pathways was observed, revealing transmembrane transport, and neuroinflammation as part of the functional modules that are disrupted across AD grading. Potential drivers of neurodegeneration predicted by networkdriven transcriptomics were monitored across different types of dementia, including progressive supranuclear palsy (PSP), mixed dementia, and frontotemporal lobar degeneration (FTLD). Epidermal growth factor receptor (EGFR) expression was significantly increased in the OB of AD and mixed dementia subjects. Moreover, a significant increment in the activation of signal transducer and activator of transcription 3 (STAT3) was exclusively detected in advanced AD stages, whereas total STAT3 levels were specifically overexpressed in mixed dementia. Furthermore, transcription factors deregulated in the OB of mixed dementia subjects such as cAMP Responsive Element Binding Protein 1 (CREB1) and AP-1 Transcription Factor Subunit (c-Jun) were not differentially modulated at olfactory level across AD grading. On the other hand, olfactory expression of this signal transducer panel was unchanged in PSP and FTLD subjects. Taken together, this study unveils cross-disease similarities and differences for specific signal transducers, providing mechanistic clues to the intriguing divergence of AD pathology across proteinopathies.
Open Access
Amyloid-driven tau accumulation on mitochondria potentially leads to cognitive deterioration in Alzheimer’s disease
(MDPI, 2021) Cuadrado-Tejedor, Mar; Pérez-González, Marta; Alfaro-Ruiz, Rocío; Badesso, Sara; Sucunza, Diego; Espelosín, María; Ursúa, Susana; Lachén Montes, Mercedes; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Luján, Rafael; García-Osta, Ana; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Despite the well-accepted role of the two main neuropathological markers (β-amyloid and tau) in the progression of Alzheimer’s disease, the interaction and specific contribution of each of them is not fully elucidated. To address this question, in the present study, an adeno-associated virus (AAV9) carrying the mutant P301L form of human tau, was injected into the dorsal hippocampi of APP/PS1 transgenic mice or wild type mice (WT). Three months after injections, memory tasks, biochemical and immunohistochemical analysis were performed. We found that the overexpression of hTauP301L accelerates memory deficits in APP/PS1 mice, but it did not affect memory function of WT mice. Likewise, biochemical assays showed that only in the case of APP/PS1-hTauP301L injected mice, an important accumulation of tau was observed in the insoluble urea fraction. Similarly, electron microscopy images revealed that numerous clusters of tau immunoparticles appear at the dendrites of APP/PS1 injected mice and not in WT animals, suggesting that the presence of amyloid is necessary to induce tau aggregation. Interestingly, these tau immunoparticles accumulate in dendritic mitochondria in the APP/PS1 mice, whereas most of mitochondria in WT injected mice remain free of tau immunoparticles. Taken together, it seems that amyloid induces tau aggregation and accumulation in the dendritic mitochondria and subsequently may alter synapse function, thus, contributing to accelerate cognitive decline in APP/PS1 mice.
Open Access
Network-driven proteogenomics unveils an aging-related imbalance in the olfactory IκBα-NFκB p65 complex functionality in Tg2576 Alzheimer’s disease mouse model
(MDPI, 2017) Palomino Alonso, Maialen; Lachén Montes, Mercedes; González Morales, Andrea; Ausín, Karina; Pérez Mediavilla, Alberto; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua, PC023-24; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Olfaction is often deregulated in Alzheimer’s disease (AD) patients, and is also impaired in transgenic Tg2576 AD mice, which overexpress the Swedish mutated form of human amyloid precursor protein (APP). However, little is known about the molecular mechanisms that accompany the neurodegeneration of olfactory structures in aged Tg2576 mice. For that, we have applied proteome- and transcriptome-wide approaches to probe molecular disturbances in the olfactory bulb (OB) dissected from aged Tg2576 mice (18 months of age) as compared to those of age matched wild-type (WT) littermates. Some over-represented biological functions were directly relevant to neuronal homeostasis and processes of learning, cognition, and behavior. In addition to the modulation of CAMP responsive element binding protein 1 (CREB1) and APP interactomes, an imbalance in the functionality of the IκBα-NFκB p65 complex was observed during the aging process in the OB of Tg2576 mice. At two months of age, the phosphorylated isoforms of olfactory IκBα and NFκB p65 were inversely regulated in transgenic mice. However, both phosphorylated proteins were increased at 6 months of age, while a specific drop in IκBα levels was detected in 18-month-old Tg2576 mice, suggesting a transient activation of NFκB in the OB of Tg2576 mice. Taken together, our data provide a metabolic map of olfactory alterations in aged Tg2576 mice, reflecting the progressive effect of APP overproduction and β-amyloid (Aβ) accumulation on the OB homeostasis in aged stages.
Open Access
Olfactory bulb neuroproteomics reveals a chronological perturbation of survival routes and a disruption of prohibitin complex during Alzheimer's disease progression
(Springer Nature, 2017) Lachén Montes, Mercedes; González Morales, Andrea; Zelaya Huerta, María Victoria; Pérez Valderrama, Estela; Ausín, Karina; Ferrer, Isidro; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua, PC025; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Olfactory dysfunction is among the earliest features of Alzheimer’s disease (AD). Although neuropathological abnormalities have been detected in the olfactory bulb (OB), little is known about its dynamic biology. Here, OB- proteome analysis showed a stage-dependent synaptic proteostasis impairment during AD evolution. In addition to progressive modulation of tau and amyloid precursor protein (APP) interactomes, network-driven proteomics revealed an early disruption of upstream and downstream p38 MAPK pathway and a subsequent impairment of Phosphoinositide-dependent protein kinase 1 (PDK1)/Protein kinase C (PKC) signaling axis in the OB from AD subjects. Moreover, a mitochondrial imbalance was evidenced by a depletion of Prohibitin-2 (Phb2) levels and a specific decrease in the phosphorylated isoforms of Phb1 in intermediate and advanced AD stages. Interestingly, olfactory Phb subunits were also deregulated across different types of dementia. Phb2 showed a specific up-regulation in mixed dementia, while Phb1 isoforms were down-regulated in frontotemporal lobar degeneration (FTLD). However, no differences were observed in the olfactory expression of Phb subunits in progressive supranuclear palsy (PSP). To sum up, our data reflect, in part, the missing links in the biochemical understanding of olfactory dysfunction in AD, unveiling Phb complex as a differential driver of neurodegeneration at olfactory level.
Open Access
Tackling the biological meaning of the human olfactory bulb dyshomeostatic proteome across neurological disorders: an integrative bioinformatic approach
(MDPI, 2021) Cartas Cejudo, Paz; Lachén Montes, Mercedes; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Olfactory dysfunction is considered an early prodromal marker of many neurodegenerative diseases. Neuropathological changes and aberrant protein aggregates occur in the olfactory bulb (OB), triggering a tangled cascade of molecular events that is not completely understood across neurological disorders. This study aims to analyze commonalities and differences in the olfactory protein homeostasis across neurological backgrounds with different spectrums of smell dysfunction. For that, an integrative analysis was performed using OB proteomics datasets derived from subjects with Alzheimer’s disease (AD), Parkinson´s disease (PD), mixed dementia (mixD), dementia with Lewy bodies (DLB), frontotemporal lobar degeneration (FTLD-TDP43), progressive supranuclear palsy (PSP) and amyotrophic lateral sclerosis (ALS) with respect to OB proteome data from neurologically intact controls. A total of 80% of the differential expressed protein products were potentially disease-specific whereas the remaining 20% were commonly altered across two, three or four neurological phenotypes. A multi-level bioinformatic characterization revealed a subset of potential disease-specific transcription factors responsible for the downstream effects detected at the proteome level as well as specific densely connected protein complexes targeted by several neurological phenotypes. Interestingly, common or unique pathways and biofunctions were also identified, providing novel mechanistic clues about each neurological disease at olfactory level. The analysis of olfactory epithelium, olfactory tract and primary olfactory cortical proteotypes in a multi-disease format will functionally complement the OB dyshomeostasis, increasing our knowledge about the neurodegenerative process across the olfactory axis.
Open Access
Amyotrophic lateral sclerosis is accompanied by protein derangements in the olfactory bulb-tract axis
(MDPI, 2020) Lachén Montes, Mercedes; Mendizuri, Naroa; Ausín, Karina; Andrés Benito, Pol; Ferrer, Isidro; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua, Ref. 0011-1411-2020-000028
Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive muscle paralysis due to the degeneration of upper and lower motor neurons. Recent studies point out an involvement of the non-motor axis during disease progression. Despite smell impairment being considered a potential non-motor finding in ALS, the pathobiochemistry at the olfactory level remains unknown. Here, we applied an olfactory quantitative proteotyping approach to analyze the magnitude of the olfactory bulb (OB) proteostatic imbalance in ALS subjects (n = 12) with respect to controls (n = 8). Around 3% of the quantified OB proteome was differentially expressed, pinpointing aberrant protein expression involved in vesicle-mediated transport, macroautophagy, axon development and gliogenesis in ALS subjects. The overproduction of olfactory marker protein (OMP) points out an imbalance in the olfactory signal transduction in ALS. Accompanying the specific overexpression of glial fibrillary acidic protein (GFAP) and Bcl-xL in the olfactory tract (OT), a tangled disruption of signaling routes was evidenced across the OB–OT axis in ALS. In particular, the OB survival signaling dynamics clearly differ between ALS and frontotemporal lobar degeneration (FTLD), two faces of TDP-43 proteinopathy. To the best of our knowledge, this is the first report on high-throughput molecular characterization of the olfactory proteostasis in ALS.