COVID-19 epidemic spread and green areas Italy and Spain between 2020 and 2021: An observational multi-country retrospective study.

Several studies have proposed that environmental factors influencing human wellbeing, such as chronic exposures to high levels of particulate matter, could indirectly or even directly affect also the severity of COVID-19 disease in case of infection by novel coronavirus SARS-COV2. This study has investigated the association between COVID-19 infections, hospitalizations or deaths and the extension of public green areas (km2 per 100,000 based on OECD data of 2014), an indicator that has been chosen as independent endpoint variable to test the research hypothesis in 10 Italian and 8 Spanish Provinces with more than 500.000 inhabitants, including capitals (Rome and Madrid) and bigger cities (Bologna, Catania, Florence, Genoa, Milan, Naples, Palermo, Turin and Venice for Italy; Barcelona, Valencia, Seville, Zaragoza, Malaga, Las Palmas and Bilbao for Spain). Two different methodologies have been applied: a bottom-up approach was applied to Spanish institutional data concerning contagions/hospitalizations/deaths and the extent of public green areas for each responder to an official questionnaire in the frame of a nationwide survey (with detailed data granularity per province) containing specific georeferenced information; a top-down approach was used for Italy, starting from the official figures of contagions/hospitalizations/deaths of each province and linking them to the OECD statistics about the extension of public green areas in the different areas. Linear and generalized models were used for statistical analyses including also PM2.5 in a multivariate approach (with annual average concentrations from official air quality monitoring stations) and were able to adjust for the different number inhabitants living in each province, in order to take into account the difference in contagion dynamics related to the different density of population. The results obtained for Spain are consistent with those observed for Italy, as for both countries, it has clearly emerged a statistically significant association between COVID-19 clinical features (contagions, hospitalizations, and deaths) and the extension of public green areas, as well as the annual average concentrations of PM2.5 (with this latter variable loosing statistical significance in some province). Therefore, the extension of public green areas and air pollution seem to have a high correlation with COVID-19 severity.

MALL, a membrane-tetra-spanning proteolipid overexpressed in cancer, is present in membraneless nuclear biomolecular condensates.

Proteolipids are proteins with unusual lipid-like properties. It has long been established that PLP and plasmolipin, which are two unrelated membrane-tetra-spanning myelin proteolipids, can be converted in vitro into a water-soluble form with a distinct conformation, raising the question of whether these, or other similar proteolipids, can adopt two different conformations in the cell to adapt their structure to distinct environments. Here, we show that MALL, another proteolipid with a membrane-tetra-spanning structure, distributes in membranes outside the nucleus and, within the nucleus, in membrane-less, liquid-like PML body biomolecular condensates. Detection of MALL in one or other environment was strictly dependent on the method of cell fixation used, suggesting that MALL adopts different conformations depending on its physical environment -lipidic or aqueous- in the cell. The acquisition of the condensate-compatible conformation requires PML expression. Excess MALL perturbed the distribution of the inner nuclear membrane proteins emerin and LAP2ß, and that of the DNA-binding protein BAF, leading to the formation of aberrant nuclei. This effect, which is consistent with studies identifying overexpressed MALL as an unfavorable prognostic factor in cancer, could contribute to cell malignancy. Our study establishes a link between proteolipids, membranes and biomolecular condensates, with potential biomedical implications.

Structure and function of the N-terminal extension of the formin INF2.

In INF2-a formin linked to inherited renal and neurological disease in humans-the DID is preceded by a short N-terminal extension of unknown structure and function. INF2 activation is achieved by Ca2+-dependent association of calmodulin (CaM). Here, we show that the N-terminal extension of INF2 is organized into two α-helices, the first of which is necessary to maintain the perinuclear F-actin ring and normal cytosolic F-actin content. Biochemical assays indicated that this helix interacts directly with CaM and contains the sole CaM-binding site (CaMBS) detected in INF2. The residues W11, L14 and L18 of INF2, arranged as a 1-4-8 motif, were identified as the most important residues for the binding, W11 being the most critical of the three. This motif is conserved in vertebrate INF2 and in the human population. NMR and biochemical analyses revealed that CaM interacts directly through its C-terminal lobe with the INF2 CaMBS. Unlike control cells, INF2 KO cells lacked the perinuclear F-actin ring, had little cytosolic F-actin content, did not respond to increased Ca2+ concentrations by making more F-actin, and maintained the transcriptional cofactor MRTF predominantly in the cytoplasm. Whereas expression of intact INF2 restored all these defects, INF2 with inactivated CaMBS did not. Our study reveals the structure of the N-terminal extension, its interaction with Ca2+/CaM, and its function in INF2 activation.

The role of outdoor and indoor air quality in the spread of SARS-CoV-2: Overview and recommendations by the research group on COVID-19 and particulate matter (RESCOP commission).

There are important questions surrounding the potential contribution of outdoor and indoor air quality in the transmission of SARS-CoV-2 and perpetuation of COVID-19 epidemic waves. Environmental health may be a critical component of COVID-19 prevention. The public health community and health agencies should consider the evolving evidence in their recommendations and statements, and work to issue occupational guidelines. Evidence coming from the current epidemiological and experimental research is expected to add knowledge about virus diffusion, COVID-19 severity in most polluted areas, inter-personal distance requirements and need for wearing face masks in indoor or outdoor environments. The COVID-19 pandemic has highlighted the need for maintaining particulate matter concentrations at low levels for multiple health-related reasons, which may also include the spread of SARS-CoV-2. Indoor environments represent even a more crucial challenge to cope with, as it is easier for the SARS-COV2 to spread, remain vital and infect other subjects in closed spaces in the presence of already infected asymptomatic or mildly symptomatic people. The potential merits of preventive measures, such as CO2 monitoring associated with natural or controlled mechanical ventilation and air purification, for schools, indoor public places (restaurants, offices, hotels, museums, theatres/cinemas etc.) and transportations need to be carefully considered. Hospital settings and nursing/retirement homes as well as emergency rooms, infectious diseases divisions and ambulances represent higher risk indoor environments and may require additional monitoring and specific decontamination strategies based on mechanical ventilation or air purification.

Determination of SARS-CoV-2 RNA in different particulate matter size fractions of outdoor air samples in Madrid during the lockdown.

BACKGROUND: Previous studies described the presence of SARS-CoV-2 in outdoor air particulate matter (PM) in urban areas of northern Italy and USA. The city of Madrid was heavily affected by COVID-19 during March-June 2020. Also, this city usually displays high concentrations of PM under several atmospheric situations. This is mandatory to assess the presence of viral RNA in PM, as an indicator of epidemic recurrence. Our study was aimed at investigating the presence of SARS-CoV-2 RNA in outdoor air samples (on PM10, PM2.5 and PM1). METHODS: Six samples of PM10, PM2.5 and PM1 were collected between the May 4th and 22nd 2020 in Madrid, on quartz fiber filters by using MCV high volume samplers (30 m3 h-1 flow) with three inlets (Digitel DHA-80) for sampling PM10, PM2.5 and PM1. RNA extraction and amplification was performed according to the protocol recently set by Setti et al.2020c in Italy. Up to three highly specific molecular marker genes (N1, N2, and RP) were used to test the presence of SARS-CoV-2 RNA. RESULTS: After RNA extraction and expression measurements of N1, N2 and RP genes from all the collected filters, no presence of SARS-CoV-2 RNA was observed. Control tests to exclude false positive results were successfully accomplished. CONCLUSIONS: No presence of SARS-CoV-2 in quartz fiber filters samplers for PM10, PM2.5 and PM1 fractions was observed in our study carried out in Madrid during the month of May 2020. Nevertheless, the absence of viral genomes could be due to different factors including: limited social interactions and economic activities resulting in reduced circulation of the coronavirus, lower daily PM concentration in outdoor air, as well as to meteorological stability and higher temperature that characterize spring season. Further research should be carried out during winter, in presence of higher viral circulation and daily PM exceedances.

Efficacy and safety of intranasal haloperidol in an acute Psychiatry Unit: a pilot study on schizophrenic patients with mild-modedate agitation.

To study the efficacy and safety of intranasal administration of 5 mg haloperidol on mild-moderate agitated patients with schizophrenia or schizoaffective disorder in an acute psychiatry unit setting.

Modelling the effects of climate change and population growth in four intensively exploited Mediterranean aquifers. The Mijas range, southern Spain.

Groundwater is key to economic growth in the Mediterranean region. This is particularly true of areas such as southern Spain, where aquifers underpin social development by supplying water to a booming tourist industry. Intensive groundwater use raises sustainability concerns, as pumping often exceeds the long-term recharge rate. Climate change and population growth are likely to exacerbate the water supply challenge in the coming years, due to the expected decrease in rainfall and to increasing competition among users. This paper examines some of the main aquifers in the Costa del Sol region, one of Spain's leading tourist destinations, where intensive groundwater extraction has led to water table drawdowns and the desiccation of all major springs. A numerical model was developed and calibrated for the purpose of evaluating the likely evolution of the system in the future. Downscaled scenarios from global circulation models were coupled with population growth forecasts to establish a range of plausible water management scenarios. Given the relatively small size of the aquifers and the limited recharge rate, the current pumping patterns appear unsustainable. Results suggest that drawdowns in excess of 150 m could take place within the next decade, thus compromising domestic supplies.

The MAL protein is crucial for proper membrane condensation at the ciliary base, which is required for primary cilium elongation.

The base of the primary cilium contains a zone of condensed membranes whose importance is not known. Here, we have studied the involvement of MAL, a tetraspanning protein that exclusively partitions into condensed membrane fractions, in the condensation of membranes at the ciliary base and investigated the importance of these membranes in primary cilium formation. We show that MAL accumulates at the ciliary base of epithelial MDCK cells. Knockdown of MAL expression resulted in a drastic reduction in the condensation of membranes at the ciliary base, the percentage of ciliated cells and the length of the cilia, but did not affect the docking of the centrosome to the plasma membrane or produce missorting of proteins to the pericentriolar zone or to the membrane of the remaining cilia. Rab8 (for which there are two isoforms, Rab8A and Rab8b), IFT88 and IFT20, which are important components of the machinery of ciliary growth, were recruited normally to the ciliary base of MAL-knockdown cells but were unable to elongate the primary cilium correctly. MAL, therefore, is crucial for the proper condensation of membranes at the ciliary base, which is required for efficient primary cilium extension.

Rethinking assessment measures of phonological development and their application in bilingual acquisition.

This article discusses the measurements for phonological and prosodic development put forward in Ingram [Ingram, D. (2002). The measurement of whole-word productions. Journal of Child Language, 29, 713-733.], while at the same time expanding the crucial measures, phonological mean length of utterance (PMLU) and proportion of whole-word proximity (PWP). The goal of the expansion is to accommodate a wider set of phenomena, specifically those related to bilingual acquisition of languages with different categories (e.g. closed syllables in German and open syllables in Spanish). Data from three monolingual Spanish children and from three bilingual German--Spanish children are presented as illustration of the modified measurements: expanded PMLU of features (ePMLU-F), expanded PMLU of syllables (ePMLU-S) and expanded PWP (ePWP). By means of measuring both features and prosodic positions, the expanded measurements do better justice to the various aspects of child phonology. Nonetheless, an important goal of this article is to stimulate discussion in order to bring our state-of-the-art closer to descriptive adequacy.

Hyperthyroidism and cardiovascular disease: an association study using big data analytics.

BACKGROUND: The cardiovascular (CV) system is profoundly affected by thyroid hormones. Both hypo- and hyperthyroidism can increase the risk of severe CV complications. OBJECTIVE: To assess the association of hyperthyroidism with major CV risk factors (CVRFs) and CV diseases (CVDs) using a big data methodology with the Savana Manager platform. MATERIAL AND METHODS: This was an observational and retrospective study. The data were obtained from the electronic medical records of the University Hospital Puerta de Hierro Majadahonda (Spain). Artificial intelligence techniques were used to extract the information from the electronic health records and Savana Manager 3.0 software was used for analysis. RESULTS: Of a total of 540,939 patients studied (53.62% females; mean age 42.2 ± 8.7 years), 5504 patients (1.02%; 69.9% women) had a diagnosis of hyperthyroidism. Patients with this diagnosis had a significantly (p < 0.0001) higher frequency of CVRFs than that found in non-hyperthyroid subjects. The higher frequency of CVRFs in patients with hyperthyroidism was observed in both women and men and in patients younger and older than 65 years of age. The total frequency of CVDs was also significantly (p < 0.0001) higher in patients diagnosed with hyperthyroidism than that found in patients without this diagnosis. The highest odds ratio values obtained were 6.40 (4.27-9.61) for embolic stroke followed by 5.99 (5.62-6.38) for atrial fibrillation. The frequency of all CVDs evaluated in patients with a diagnosis of hyperthyroidism was significantly higher in both women and men, as well as in those younger and older than 65 years, compared to subjects without this diagnosis. A multivariate regression analysis showed that hyperthyroidism was significantly and independently associated with all the CVDs evaluated except for embolic stroke. CONCLUSION: The data from this hospital cohort suggest that there is a significant association between the diagnosis of hyperthyroidism and the main CVRFs and CVDs in our population, regardless of the age and gender of the patients. Our study, in addition to confirming this association, provides useful information for understanding the applicability of artificial intelligence techniques to "real-world data and information".

Monitoring the mass, eigenfrequency, and quality factor of mammalian cells.

The regulation of mass is essential for the development and homeostasis of cells and multicellular organisms. However, cell mass is also tightly linked to cell mechanical properties, which depend on the time scales at which they are measured and change drastically at the cellular eigenfrequency. So far, it has not been possible to determine cell mass and eigenfrequency together. Here, we introduce microcantilevers oscillating in the Ångström range to monitor both fundamental physical properties of the cell. If the oscillation frequency is far below the cellular eigenfrequency, all cell compartments follow the cantilever motion, and the cell mass measurements are accurate. Yet, if the oscillating frequency approaches or lies above the cellular eigenfrequency, the mechanical response of the cell changes, and not all cellular components can follow the cantilever motions in phase. This energy loss caused by mechanical damping within the cell is described by the quality factor. We use these observations to examine living cells across externally applied mechanical frequency ranges and to measure their total mass, eigenfrequency, and quality factor. The three parameters open the door to better understand the mechanobiology of the cell and stimulate biotechnological and medical innovations.

No gender differences in the 24-month course of non-invasive liver fibrosis markers after DAA therapy in HCV-mono and HCV/HIV-coinfected patients.

Untreated HCV mono and HCV/HIV coinfected women have lower degrees of liver fibrosis (LF) compared to men. Direct acting antiviral (DAA) therapy attains viral eradication in > 90% of patients with progressive LF decline in parallel. Gender-related differences in LF regression in the long term assessed by non-invasive liver fibrosis markers (NILFM) in HCV mono and HCV/HIV coinfected after DAA treatment have not been explored so far. 374 HCV-infected adult patients, 214 of them HCV/HIV coinfected, were followed-up for 24 months after starting DAA therapy. LF was assessed by NILFM: transient elastometry (TE) and several biochemical indexes (APRI, Forns, FIB-4). Men had significantly more advanced LF at baseline than women assessed by NILFM. No LF differences at baseline in age, HIV coinfection course (CD4, HIV viral load), and HCV features (HCV viral load, genotype) were detected. No significant gender differences in LF decline after comparing 24-month and baseline LF values were observed. LF changes after DAA therapy were similar in HCV mono and HCV/HIV coinfected patients and in both sexes. Gender did not influence the course of LF decline after DAA assessed by NILFM: TE (P = 0.8), APRI (P = 0.9), Forns (P = 0.4) and FIB-4 (P = 0.7) by multivariate analysis. No gender differences in the 24 month LF decline after DAA with independence of having HCV mono or HCV/HIV coinfection were found.

Primary Hyperparathyroidism and Cardiovascular Disease: An Association Study Using Clinical Natural Language Processing Systems and Big Data Analytics.

Primary hyperparathyroidism (PHPT) seems to be associated with different cardiovascular diseases (CVDs). We evaluated the association of PHPT with major CV risk factors (CVRFs) and CVDs by using artificial intelligence (AI) tools. An observational and retrospective study was conducted using data from the electronic health records (EHRs) of the Hospital Universitario Puerta de Hierro Majadahonda (Spain). Of a total of 699,157 patients over 18 years of age studied (54.7% females), 6515 patients (0.9%; 65.4% women; mean age 67.6 ± 15.9 years) had a diagnosis of PHPT. The overall frequencies of hypertension, dyslipidemia, diabetes mellitus, and smoking habit in the cohort of patients with PTHP were all significantly (p < 0.001) higher than those found in patients without a diagnosis of PTHP. The total frequency of stroke, ischemic heart disease, atrial fibrillation, deep vein thrombosis, and pulmonary embolism in the cohort of PHPT patients were significantly (p < 0.001) higher than that found in patients without the diagnosis of PHPT. A multivariate regression analysis showed that PHPT was significantly (p < 0.001) and independently associated with all the CVDs evaluated. Our data show that there is a significant association between the diagnosis of PHPT and the main CVRFs and CVDs in our hospital population.

In mitosis integrins reduce adhesion to extracellular matrix and strengthen adhesion to adjacent cells.

To enter mitosis, most adherent animal cells reduce adhesion, which is followed by cell rounding. How mitotic cells regulate adhesion to neighboring cells and extracellular matrix (ECM) proteins is poorly understood. Here we report that, similar to interphase, mitotic cells can employ integrins to initiate adhesion to the ECM in a kindlin- and talin-dependent manner. However, unlike interphase cells, we find that mitotic cells cannot engage newly bound integrins to actomyosin via talin or vinculin to reinforce adhesion. We show that the missing actin connection of newly bound integrins leads to transient ECM-binding and prevents cell spreading during mitosis. Furthermore, ß1 integrins strengthen the adhesion of mitotic cells to adjacent cells, which is supported by vinculin, kindlin, and talin1. We conclude that this dual role of integrins in mitosis weakens the cell-ECM adhesion and strengthens the cell-cell adhesion to prevent delamination of the rounding and dividing cell.

Retrospective study of the epidemiological risk and serological diagnosis of human babesiosis in Asturias, Northwestern Spain.

BACKGROUND: Babesiosis is a globally growing tick-borne disease in humans. Severe babesiosis caused by Babesia divergens has been reported in two patients from Asturias (Northwestern Spain), suggesting an undetected risk for the disease. To analyze this risk, we retrospectively evaluated the seroprevalence of babesiosis in the Asturian population from 2015 through 2017, a period covering the intermediate years in which these two severe cases occurred. METHODS: Indirect fluorescent assay (IFA) and Western blot (WB) were performed to detect B. divergens IgG antibodies in 120 serum samples from Asturian patients infected with the tick-transmitted spirochete Borrelia burgdorferi sensu lato, a condition that indicates exposure to tick bites. RESULTS: This retrospective study confirmed a B. divergens seroprevalence rate of 39.2% according to IFA results. B. divergens incidence was 7.14 cases/100,000 population, exceeding previously reported seroprevalence rates. No differences in epidemiology and risk factors were found between patients infected solely with B. burgdorferi s.l. and those infected with B. burgdorferi s.l. and with IgG antibodies against B. divergens. This last group of patients lived in Central Asturias, had a milder clinical course and, according to WB results, developed different humoral responses against B. divergens. CONCLUSIONS: Babesia divergens parasites have circulated for several years in Asturias. Epidemiological evidence of babesiosis makes Asturias an emerging risk area for this zoonosis. Human babesiosis could also be relevant in other Spanish and European regions affected by borreliosis. Hence, the potential risk of babesiosis on human health in Asturias and other European forest regions needs to be addressed by the health authorities.

The deep inferior epigastric artery perforator (DIEAP) flap for total glossectomy reconstruction.

PURPOSE: Total or subtotal glossectomy following the resection of intraoral tumors causes significant morbidity. However, which reconstructive technique is the most successful remains controversial. PATIENTS AND METHODS: After approval by the Ethics Committee, charts were reviewed retrospectively for patients treated at the Oral and Maxillofacial Surgery Department, University Hospital La Paz (Madrid, Spain), during a 3-year period (2005-2008). All were reconstructed with a deep inferior epigastric artery perforator (DIEAP) flap after total glossectomy. Data collected included affiliation data, extent of extirpation, type of reconstruction, and surgical outcome, including donor-site morbidity, complications, and functional results. RESULTS: Seven patients (5 men, 71.4%; 2 women, 28.6%) with primary squamous cell carcinoma of the tongue underwent total glossectomy and simultaneous microsurgical reconstruction with a DIEAP flap. In all cases, the flap was harvested with a fusiform shape oriented craniocaudally and limited to zone 1. The average size of the flap was 16.7 × 7.2 cm. Functional outcome related to swallowing was poor; 57.1% of the patients required a permanent gastrostomy. Speech was considered intelligible in 85.7% of cases by 2 independent observers. The surgical outcome was uneventful in most of the cases, with only 1 case of local dehiscence at the mouth floor. None of the cases developed abdominal wall dehiscence or an abdominal hernia at mid- or long-term follow-up. CONCLUSIONS: The DIEAP flap is a reliable alternative for tongue reconstruction. It provides a large volume of soft tissue for transfer and is predictable and stable over time with low donor-site morbidity.

Correlative confocal and scanning electron microscopy of cultured cells without using dedicated equipment.

This protocol enables correlative light and electron microscopy (CLEM) imaging of cell surface features without using dedicated equipment. Cells are cultured and fixed on transparent substrates for confocal microscopy imaging. No conductive coating is employed in the scanning electron microscopy workflow, providing a clean cell surface observation, with fiducial markers assisting alignment of optical and topographical images. This protocol describes CLEM imaging for midbody remnants in MDCK cells but can also be applied to different cell types and surface features. For complete details on the use and execution of this protocol, please refer to Casares-Arias et al. (2020).

The fibula osteomyocutaneous flap for mandible reconstruction: a 15-year experience.

PURPOSE: This report documents our experience over the previous 15 years using free vascularized fibular flaps for comprehensive reconstruction of large defects in the mandible, after combined resections of aggressive, malignant odontogenic tumors or for post-traumatic defects. PATIENTS AND METHODS: Charts were reviewed retrospectively for 117 consecutive patients who underwent microsurgical reconstruction of the oromandibular complex with a fibula osteocutaneous or osteomyocutaneous free flap over a 15-year period, with an average follow-up of 4 years. All charts were reviewed retrospectively for tumor type, stage and location, surgical procedure performed (including type of plate used), dental restoration if done, the use of pre- or postoperative radiotherapy, length of follow-up, and evidence of complications. RESULTS: Fibula osteocutaneous free flaps were used for reconstruction in 117 patients, of whom 60% were men (mean age, 57.1 years) and 40% were women (mean age, 56.6 years). Most cases (61.1%) were secondary to oral malignancies (89.1% of these were squamous cell carcinoma). Thirty-one patients (26.5%) developed postoperative complications, including hardware failure or intolerance in 16 patients (13.7%), total or partial flap failure in 10 patients (8.5%), wound infection in 3 patients (2.6%), and peroneal nerve damage in 2 patients (1.7%). Regarding donor site morbidity, calf paresthesias were recorded in 21% of cases. Similar rates of claw-toe deformity were also observed. CONCLUSIONS: In our opinion, the free fibula osteocutaneous flap is the most versatile and reliable option for microsurgical reconstruction of large mandibular defects. It provides a large quantity of bone, which is easily shaped to passively adapt to the remaining mandible. The bone height is suitable for an implant-based prosthetic restoration. Preoperative mapping of the cutaneous perforators of the skin paddle improves the versatility of the flap design and decreases the morbidity at the donor site. In selected cases, other options (iliac crest or scapular free flap) may also be considered.

A Model for Primary Cilium Biogenesis by Polarized Epithelial Cells: Role of the Midbody Remnant and Associated Specialized Membranes.

Primary cilia are solitary, microtubule-based protrusions surrounded by a ciliary membrane equipped with selected receptors that orchestrate important signaling pathways that control cell growth, differentiation, development and homeostasis. Depending on the cell type, primary cilium assembly takes place intracellularly or at the cell surface. The intracellular route has been the focus of research on primary cilium biogenesis, whereas the route that occurs at the cell surface, which we call the "alternative" route, has been much less thoroughly characterized. In this review, based on recent experimental evidence, we present a model of primary ciliogenesis by the alternative route in which the remnant of the midbody generated upon cytokinesis acquires compact membranes, that are involved in compartmentalization of biological membranes. The midbody remnant delivers part of those membranes to the centrosome in order to assemble the ciliary membrane, thereby licensing primary cilium formation. The midbody remnant's involvement in primary cilium formation, the regulation of its inheritance by the ESCRT machinery, and the assembly of the ciliary membrane from the membranes originally associated with the remnant are discussed in the context of the literature concerning the ciliary membrane, the emerging roles of the midbody remnant, the regulation of cytokinesis, and the role of membrane compartmentalization. We also present a model of cilium emergence during evolution, and summarize the directions for future research.

Midbody Remnant Inheritance Is Regulated by the ESCRT Subunit CHMP4C.

The inheritance of the midbody remnant (MBR) breaks the symmetry of the two daughter cells, with functional consequences for lumen and primary cilium formation by polarized epithelial cells, and also for development and differentiation. However, despite its importance, neither the relationship between the plasma membrane and the inherited MBR nor the mechanism of MBR inheritance is well known. Here, the analysis by correlative light and ultra-high-resolution scanning electron microscopy reveals a membranous stalk that physically connects the MBR to the apical membrane of epithelial cells. The stalk, which derives from the uncleaved side of the midbody, concentrates the ESCRT machinery. The ESCRT CHMP4C subunit enables MBR inheritance, and its depletion dramatically reduces the percentage of ciliated cells. We demonstrate (1) that MBRs are physically connected to the plasma membrane, (2) how CHMP4C helps maintain the integrity of the connection, and (3) the functional importance of the connection.