Bilateral cochlear implants in a MELAS patient.

BACKGROUND: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a maternally inherited mitochondrial disease that affects various systems in the body, particularly the brain, nervous system, and muscles. Among these systems, sensorineural hearing loss is a common additional symptom. METHODS: A 42-year-old female patient with MELAS who experienced bilateral profound deafness and underwent bilateral sequential cochlear implantation (CIs). Speech recognition and subjective outcomes were evaluated. RESULTS: Following the first CI follow-up, the patient exhibited improved speech recognition ability and decided to undergo the implantation of the second ear just two months after the initial CI surgery. The second CI also demonstrated enhanced speech recognition ability. Subjective outcomes were satisfactory for bilateral CIs. CONCLUSIONS: MELAS patients receiving bilateral CIs can attain satisfactory post-CI speech recognition, spatial hearing, and sound qualities.

Galectin-3 aggravates microglial activation and tau transmission in tauopathy.

Alzheimer's disease is characterized by the accumulation of amyloid-ß plaques, aggregation of hyperphosphorylated tau (pTau), and microglia activation. Galectin-3 (Gal3) is a ß-galactoside-binding protein that has been implicated in amyloid pathology. Its role in tauopathy remains enigmatic. Here, we showed that Gal3 was upregulated in the microglia of humans and mice with tauopathy. pTau triggered the release of Gal3 from human induced pluripotent stem cell-derived microglia in both its free and extracellular vesicular-associated (EV-associated) forms. Both forms of Gal3 increased the accumulation of pathogenic tau in recipient cells. Binding of Gal3 to pTau greatly enhanced tau fibrillation. Besides Gal3, pTau was sorted into EVs for transmission. Moreover, pTau markedly enhanced the number of EVs released by iMGL in a Gal3-dependent manner, suggesting a role of Gal3 in biogenesis of EVs. Single-cell RNA-Seq analysis of the hippocampus of a mouse model of tauopathy (THY-Tau22) revealed a group of pathogenic tau-evoked, Gal3-associated microglia with altered cellular machineries implicated in neurodegeneration, including enhanced immune and inflammatory responses. Genetic removal of Gal3 in THY-Tau22 mice suppressed microglia activation, reduced the level of pTau and synaptic loss in neurons, and rescued memory impairment. Collectively, Gal3 is a potential therapeutic target for tauopathy.

Long-term auditory performance and psychosocial benefits of cochlear implantation in Mandarin-speaking older adults.

PURPOSE: Although previous studies have shown the efficacy of cochlear implants (CIs) in older adults, no study written in English has focused on Mandarin-speaking older recipients. Mandarin is a tonal language, it is hard to lip-read and tone recognition for CI users. This study aimed to evaluate the long-term post-CI outcomes in Mandarin-speaking older adults and the difference between them and younger recipients. MATERIALS AND METHODS: Forty-six post-lingually deafened adults were included. Speech perception tests (vowel, consonant, disyllable words, Mandarin monosyllable recognition test, and categories of audiology performance were evaluated) and psychosocial scale were evaluated. RESULTS: There were no significant differences between older and younger recipients in post-CI open-set speech perception. However, older recipients had significantly lower social and total scores in the subjective questionnaire than younger recipients. In both duration of deafness less than seven years and hearing years in life over 92.6 %, older recipients had no less capable speech perception than in younger. CONCLUSION: Mandarin-speaking older recipients can improve not only speech perception but also psychosocial benefits. Well hearing experience may confer an advantage to older recipients, despite their older implanted age. These results can help provide pre-CI consultation guidelines for older Mandarin-speaking recipients.

Phase separation driven by interchangeable properties in the intrinsically disordered regions of protein paralogs.

Paralogs, arising from gene duplications, increase the functional diversity of proteins. Protein functions in paralog families have been extensively studied, but little is known about the roles that intrinsically disordered regions (IDRs) play in their paralogs. Without a folded structure to restrain them, IDRs mutate more diversely along with evolution. However, how the diversity of IDRs in a paralog family affects their functions is unexplored. Using the RNA-binding protein Musashi family as an example, we applied multiple structural techniques and phylogenetic analysis to show how members in a paralog family have evolved their IDRs to different physicochemical properties but converge to the same function. In this example, the lower prion-like tendency of Musashi-1's IDRs, rather than Musashi-2's, is compensated by its higher α-helical propensity to assist their assembly. Our work suggests that, no matter how diverse they become, IDRs could evolve different traits to a converged function, such as liquid-liquid phase separation.

Liquid-liquid phase separation and extracellular multivalent interactions in the tale of galectin-3.

Liquid-liquid phase separation (LLPS) explains many intracellular activities, but its role in extracellular functions has not been studied to the same extent. Here we report how LLPS mediates the extracellular function of galectin-3, the only monomeric member of the galectin family. The mechanism through which galectin-3 agglutinates (acting as a "bridge" to aggregate glycosylated molecules) is largely unknown. Our data show that its N-terminal domain (NTD) undergoes LLPS driven by interactions between its aromatic residues (two tryptophans and 10 tyrosines). Our lipopolysaccharide (LPS) micelle model shows that the NTDs form multiple weak interactions to other galectin-3 and then aggregate LPS micelles. Aggregation is reversed when interactions between the LPS and the carbohydrate recognition domains are blocked by lactose. The proposed mechanism explains many of galectin-3's functions and suggests that the aromatic residues in the NTD are interesting drug design targets.