Evolution and development of extraocular motor neurons, nerves and muscles in vertebrates

Annals of Anatomy - Anatomischer Anzeiger, Journal Year: 2024, Volume and Issue: 253, P. 152225 - 152225

Published: Feb. 10, 2024

Language: Английский

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Understanding the role of inflammation in sensorineural hearing loss: Current goals and future prospects

Brain‐X, Journal Year: 2023, Volume and Issue: 1(3)

Published: Sept. 1, 2023

Abstract Sensorineural hearing loss (SNHL) is a common otologic condition caused by damage to hair cells and spiral ganglion neurons that affects transmission pathways. Most of these cannot be regenerated, there has been no breakthrough in regeneration techniques for inner ear cells. SNHL high incidence rate can cause variety clinical symptoms, greatly impacting people's daily lives. With limited treatments, the search critical targets urgent. Studies have shown inflammation prevalent pathogenesis plays significant role it. Inflammation normal body defense response, systemic anti‐inflammatory approach undesirable. It crucial us identify potential take measures specifically targeting those with minimal impact. This paper firstly describes various types then provides an overview interactions between cochlear immunity, microcirculation, vascular spasm, glutamate metabolism finally comprehensively examines feasibility interactions. expected facilitate development targeted anti‐inflammation provide strategies approaches treating SNHL.

Language: Английский

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Gene networks and the evolution of olfactory organs, eyes, hair cells and motoneurons: a view encompassing lancelets, tunicates and vertebrates

Frontiers in Cell and Developmental Biology, Journal Year: 2024, Volume and Issue: 12

Published: March 12, 2024

Key developmental pathways and gene networks underlie the formation of sensory cell types structures involved in chemosensation, vision mechanosensation, efferents these inputs can activate. We describe similarities differences selected species three main chordate groups, lancelets, tunicates, vertebrates, leading to divergent development olfactory receptors, eyes, hair cells motoneurons. The lack appropriately posited expression certain transcription factors lancelets tunicates prevents them from developing vertebrate-like receptors although they generate alternative for chemosensation vision. Lancelets mechanosensory associated with sensation acoustic stimuli, but have gravisensitive organs ciliated epidermal that may (and some cases clearly do) provide mechanosensation thus capacity respond movement relative surrounding water. Although functionally analogous vertebrate vestibular apparatus lateral line, homology is questionable due key Neurog Atoh1/7, on which depends. cell-bearing inner ear line likely represent major evolutionary advances specific vertebrates. Motoneurons develop vertebrates under control ventral signaling molecule hedgehog/sonic hedgehog ( Hh,Shh ), against an opposing inhibitory effect mediated by dorsal molecules. Many elements Shh -signaling downstream genes specifying differentiating motoneurons are also exhibited repertoire MNs broader, indicating greater diversity motoneuron differentiation programs.

Language: Английский

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Irx3/5 Null Deletion in Mice Blocks Cochlea‐Saccule Segregation and Disrupts the Auditory Tonotopic Map

The Journal of Comparative Neurology, Journal Year: 2024, Volume and Issue: 532(12)

Published: Dec. 1, 2024

A gene cadre orchestrates the normal development of sensory and non-sensory cells in inner ear, segregating cochlea with a distinct tonotopic sound frequency map, similar brain projection, five vestibular end-organs. However, role genes driving ear is largely unknown. Here, we show double deletion Iroquois homeobox 3 5 transcription factors (Irx3/5 DKO) leads to fusion saccule cochlear base. The overlying otoconia tectorial membranes are absent Irx3/5 DKO primary auditory neurons project fibers both hair cells. central neuronal projections from apex-base contour not fully segregated into dorsal ventral innervation nucleus, obliterating characteristic map. Additionally, reveals pronounced cochlear-apex-vestibular "vestibular-cochlear" nerve (VCN) bilateral connection that less noticeable wild-type control mice. Moreover, incomplete segregation apex base expands connect nuclei. results suggest mammalian derived lagena reminiscent sarcopterygians. Thus, Irx3 potential evolutionary branch-point necessary for balance-sound segregation, which fused saccule-cochlea organization.

Language: Английский

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Fish hearing revealed: Do we understand hearing in critical fishes and marine tetrapods

The Journal of the Acoustical Society of America, Journal Year: 2023, Volume and Issue: 154(5), P. 3019 - 3026

Published: Nov. 1, 2023

Hearing evolved in lampreys with a frequency range of 50–200 Hz. This hearing is comparable to that elasmobranchs, most non-teleosts, and lungfish. Elasmobranchs likely use the saccule papilla neglecta (PN) for hearing. In non-teleosts teleosts, lungfish, certain tetrapods sensor sound reception while lagena PN are important gravistatic sensing. Coelacanth have basilar (BP) coelacanth tetrapods, hair cells BP contact tectorial membrane. These membranes transmit mechanical vibrations. A cochlear aqueduct (CA) provides connection between cerebrospinal fluid has sodium rich space potassium endolymph known vertebrates. unique feature basic sarcopterygians, intracranial joint, never developed actinopterygians been lost lungfish tetrapods. The coelacanths thought generate pressure joint will be transmitted CA. Lungs or swim bladder not forming Chondrichthyes, structures major impact on teleosts

Language: Английский

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Signaling pathways regulating the immune function of cochlear supporting cells and their involvement in cochlear pathophysiology

Glia, Journal Year: 2023, Volume and Issue: 72(4), P. 665 - 676

Published: Nov. 7, 2023

The inner ear, including the cochlea, used to be regarded as an immune-privileged site because of its immunologically isolated environment caused by blood-labyrinthine barrier. Cochlear resident macrophages, which originate from yolk sac or fetal liver during embryonic stage and are maintained after birth, distributed throughout various regions cochlear duct. Intriguingly, these cells absent in organ Corti, where hair (HCs) supporting (SCs) located, except for a limited number ionized calcium-binding adapter molecule 1 (Iba1)-positive cells. Instead, SCs exert glial functions varying quiescent emergency state. Notably, acquire nature macrophages begin secrete inflammatory cytokines viral infection is ostensibly unprotected owing lack general macrophages. This review provides overview both positive negative enabled macrophage phenotypes upon focusing on signaling pathways that regulate functions. former function protects HCs inducting type I interferons, latter induces HC death necroptosis, leading sensorineural hearing loss. Thus, play contradictory roles immune with acquired phenotypes; thereby, they favorable unfavorable HCs, pivotal role function.

Language: Английский

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Influence of inner ear impedance on middle ear sound transfer functions

Heliyon, Journal Year: 2024, Volume and Issue: 10(6), P. e27758 - e27758

Published: March 1, 2024

IntroductionFor experimental studies on sound transfer in the middle ear, it may be advantageous to perform measurements without inner ear. In this case, is important know influence of ear impedance function (METF). Previous provide contradictory results regard. With current study, we investigate more detail and find possible reasons for deviations previous studies.Methods11 fresh frozen temporal bones were prepared our study. The factors related impedance, including round window membrane stiffness, cochleostomy, cochlea fluid destruction involved design. After measuring intact specimen as a reference (step 1), was punctured 2), then completely removed 3). cochleostomy performed 4) before cochlear carefully suctioned through scala tympani 5) vestibuli 6). Finally, destroyed by drilling 7). Translational rotational movement stapes footplate measured calculated at each step. steps compared quantify effect changing process drainage.ResultsAs decreases from step 1 7, amplitudes METF curves frequency gradually increase general. From 6 on, are significantly different with respect group high frequencies above 3 kHz. differences dependent. However, significant decrement motion appears 4.5 kHz 5.ConclusionThis study confirms only higher (≥3 kHz). motions sensitive drainage frequency. Study that found no due incomplete cochlea.

Language: Английский

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Single-cell atlas comparison across vertebrates reveals auditory cell evolution and mechanisms for hair cell regeneration

Communications Biology, Journal Year: 2024, Volume and Issue: 7(1)

Published: Dec. 19, 2024

Mammals suffer permanent hearing impairment from the loss of auditory hair cells due to their inability regenerate. In contrast, lower vertebrates exhibit extraordinary capacity for cell regeneration and restoration, but mechanisms remain unclear. Here we characterize single-cell atlas Xenopus laevis inner ear perform a comprehensive comparison with mouse model. An exceptionally conserved neuronal type is discovered. The results reveal that outer (OHCs) exist exclusively in mammals. Importantly, our analyses an orchestrated gene expression program Xenopus, characterized by upregulation regeneration-related genes, coupled downregulation proliferation inhibitory genes. These findings unveil natural feature regenerative provide molecular evolutionary evidences differential capacities across vertebrates. This work offers insights amphibians into developing strategies solve challenges humans. Comparison between highly mice reveals evolution sheds light on regeneration.

Language: Английский

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THE ROLE OF FGF15/FGF19 IN THE DEVELOPMENT OF THE CENTRAL NERVOUS SYSTEM, EYES AND INNER EARS IN VERTEBRATES

Tissue and Cell, Journal Year: 2024, Volume and Issue: 91, P. 102619 - 102619

Published: Nov. 15, 2024

Language: Английский

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