Rhes, a striatal enriched protein, regulates post-translational small-ubiquitin-like-modifier (SUMO) modification of nuclear proteins and alters gene expression

Rhes (Ras homolog enriched in the striatum), a multifunctional protein that regulates striatal functions associated with motor behaviors and neurological diseases, can shuttle from cell to cell via the formation of tunneling-like nanotubes (TNTs). However, the mechanisms by which Rhes mediates diverse functions remain unclear. Rhes is a small GTPase family member which contains a unique C-terminal Small Ubiquitin-like Modifier (SUMO) E3-like domain that promotes SUMO post-translational modification of proteins (SUMOylation) by promoting "cross-SUMOylation" of the SUMO enzyme SUMO E1 (Aos1/Uba2) and SUMO E2 ligase (Ubc-9). Nevertheless, the identity of the SUMO substrates of Rhes remains largely unknown. Here, by combining high throughput interactome and SUMO proteomics, we report that Rhes regulates the SUMOylation of nuclear proteins that are involved in the regulation of gene expression. Rhes increased the SUMOylation of histone deacetylase 1 (HDAC1) and histone 2B, while decreasing SUMOylation of heterogeneous nuclear ribonucleoprotein M (HNRNPM), protein polybromo-1 (PBRM1) and E3 SUMO-protein ligase (PIASy). We also found that Rhes itself is SUMOylated at 6 different lysine residues (K32, K110, K114, K120, K124, and K245). Furthermore, Rhes regulated the expression of genes involved in cellular morphogenesis and differentiation in the striatum, in a SUMO-dependent manner. Our findings thus provide evidence for a previously undescribed role for Rhes in regulating the SUMOylation of nuclear targets and in orchestrating striatal gene expression via SUMOylation.

SUMO modifies GβL and mediates mTOR signaling

The mechanistic target of rapamycin (mTOR) signaling is influenced by multiple regulatory proteins and post-translational modifications; however, underlying mechanisms remain unclear. Here, we report a novel role of small ubiquitin-like modifier (SUMO) in mTOR complex assembly and activity. By investigating the SUMOylation status of core mTOR components, we observed that the regulatory subunit, GβL (G protein β-subunit-like protein, also known as mLST8), is modified by SUMO1, 2, and 3 isoforms. Using mutagenesis and mass spectrometry, we identified that GβL is SUMOylated at lysine sites K86, K215, K245, K261, and K305. We found that SUMO depletion reduces mTOR-Raptor (regulatory protein associated with mTOR) and mTOR-Rictor (rapamycin-insensitive companion of mTOR) complex formation and diminishes nutrient-induced mTOR signaling. Reconstitution with WT GβL but not SUMOylation-defective KR mutant GβL promotes mTOR signaling in GβL-depleted cells. Taken together, we report for the very first time that SUMO modifies GβL, influences the assembly of mTOR protein complexes, and regulates mTOR activity.

Ribosome Profiling and Mass Spectrometry Reveal Widespread Mitochondrial Translation Defects in a Striatal Cell Model of Huntington Disease

Huntington disease (HD) is caused by an expanded polyglutamine mutation in huntingtin (mHTT) that promotes prominent atrophy in the striatum and subsequent psychiatric, cognitive deficits, and choreiform movements. Multiple lines of evidence point to an association between HD and aberrant striatal mitochondrial functions; however, the present knowledge about whether (or how) mitochondrial mRNA translation is differentially regulated in HD remains unclear. We found that protein synthesis is diminished in HD mitochondria compared to healthy control striatal cell models. We utilized ribosome profiling (Ribo-Seq) to analyze detailed snapshots of ribosome occupancy of the mitochondrial mRNA transcripts in control and HD striatal cell models. The Ribo-Seq data revealed almost unaltered ribosome occupancy on the nuclear-encoded mitochondrial transcripts involved in oxidative phosphorylation (SDHA, Ndufv1, Timm23, Tomm5, Mrps22) in HD cells. By contrast, ribosome occupancy was dramatically increased for mitochondrially encoded oxidative phosphorylation mRNAs (mt-Nd1, mt-Nd2, mt-Nd4, mt-Nd4l, mt-Nd5, mt-Nd6, mt-Co1, mt-Cytb, and mt-ATP8). We also applied tandem mass tag-based mass spectrometry identification of mitochondrial proteins to derive correlations between ribosome occupancy and actual mature mitochondrial protein products. We found many mitochondrial transcripts with comparable or higher ribosome occupancy, but diminished mitochondrial protein products, in HD. Thus, our study provides the first evidence of a widespread dichotomous effect on ribosome occupancy and protein abundance of mitochondria-related genes in HD.

Morpho-anatomical characterization and DNA barcoding of Artemesia vulgaris L

Artemisia vulgaris L. belongs to Asteraceae, is a herbal plant that has various benefits in the medical field, so that its use in the medical field can be explored optimally, the plant must be thoroughly identified. This study aims to identify A. vulgaris both in terms of descriptive morpho-anatomy and DNA barcoding using BLAST and phylogenetic tree reconstruction. The morpho-anatomical character was observed on root, stem, and leaf. DNA barcoding analysis was carried out through amplification and alignment of the rbcL and matK genes. All studies were conducted on three samples from Taman Husada (Medicinal Plant Garden) Graha Famili Surabaya, Indonesia. The anatomical slide was prepared by the paraffin method. Morphological studies revealed that the leaves of A. vulgaris both on the lower-middle part and on the upper part of the stem have differences, especially in the character of the stipules, petioles, and incisions they have. Meanwhile, from the study of anatomy, A. vulgaris has an anomocytic type of stomata and its distribution is mostly on the ventral part of the leaves. Through the BLAST process and phylogenetic tree reconstruction, the plant sequences being studied are closely related to several species of the genus Artemisia as indicated by a percentage identity above 98% and branch proximity between taxa in the reconstructed phylogenetic tree.

Curbing Rhes Actions: Mechanism-based Molecular Target for Huntington's Disease and Tauopathies

A highly interconnected network of diverse brain regions is necessary for the precise execution of human behaviors, including cognitive, psychiatric, and motor functions. Unfortunately, degeneration of specific brain regions causes several neurodegenerative disorders, but the mechanisms that elicit selective neuronal vulnerability remain unclear. This knowledge gap greatly hinders the development of effective mechanism-based therapies, despite the desperate need for new treatments. Here, we emphasize the importance of the Rhes (Ras homolog-enriched in the striatum) protein as an emerging therapeutic target. Rhes, an atypical small GTPase with a SUMO (small ubiquitin-like modifier) E3-ligase activity, modulates biological processes such as dopaminergic transmission, alters gene expression, and acts as an inhibitor of motor stimuli in the brain striatum. Mutations in the Rhes gene have also been identified in selected patients with autism and schizophrenia. Moreover, Rhes SUMOylates pathogenic form of mutant huntingtin (mHTT) and tau, enhancing their solubility and cell toxicity in Huntington's disease and tauopathy models. Notably, Rhes uses membrane projections resembling tunneling nanotubes to transport mHTT between cells and Rhes deletion diminishes mHTT spread in the brain. Thus, we predict that effective strategies aimed at diminishing brain Rhes levels will prevent or minimize the abnormalities that occur in HD and tauopathies and potentially in other brain disorders. We review the emerging technologies that enable specific targeting of Rhes in the brain to develop effective disease-modifying therapeutics.

Unraveling the secrets of Eclipta alba (L.) Hassk.: a comprehensive study of morpho-anatomy and DNA barcoding

Safety regarding herbal products is very necessary; therefore, routine identification of raw materials should be performed to ensure that the raw materials used in pharmaceutical products are suitable for their intended use. In order for the identification-related data obtained to be accurate, the identification of various kinds of markers is also very necessary. The purpose of this study was to describe the characteristics of Eclipta alba (L.) Hassk. based on qualitative morpho-anatomical markers and quantitative DNA coding. The morphology of this plant has herbaceous habit with a taproot and a stem with branches that appear from the middle. Leaves are single type imperfectly arranged oppositely, lanceolatus, finely serrated on the edges, tapered at the base, pointed at the end, and have a pinnate and hairy leaf surface. The flowers consist of ray flowers and tube flowers with a cup shape. Meanwhile, in terms of anatomy, E. alba has aerenchyma, which are scattered in the cortex of the root and stem. In addition, there are anisocytic stomata, glandular trichomes, and non-glandural trichomes with an elongated shape accompanied by ornamentation found on the leaf epidermis. The results of sequence alignment and phylogenetic tree reconstruction show that the sample plants are closely related to species in the genus Eclipta.

Links between socio-demographic characteristics and body mass index to colorectal cancer in North Borneo, Malaysia: A case-control study

INTRODUCTION

The fourth leading cause of cancer-related mortality and morbidity worldwide is colorectal cancer (CRC). Numerous reasons have contributed to the massive rise in CRC cases, for which Asian nations differ significantly in terms of risk incidence rates. The objectives of this study were to, first, identify the socio-demographic characteristics of those of North Borneo ethnicity and body mass index (BMI) and, second, determine the association of these factors with CRC. This research will contribute to preventing this form of cancer.

MATERIALS AND METHODS

This study is an analysis of a matched case-control study with a ratio of 1:2. The case group contained 206 respondents, and the control group contained 412. All CRC cases were confirmed with the histological results. The control group was matched for links between age, sex and ethnicity with CRC. The Statistical Package for Social Sciences Statistics (SPSS) IBM version 28.0 was used to conduct descriptive analysis using chi-squared testing and simple logistic regression. The statistical significance was P < 0.05.

RESULT

Overall, 618 respondents took part in this survey, of which 256 (41.4%) were female and 362 (58.6%) were male. The maximum age was 76, with a mean age ± SD of 53.17 ± 11.4. Those of Bajau ethnicity comprised 24.6% (152) of the population, followed by Dusun with 22.8% (141), Kadazan with 17.6% (109%), other North Borneo ethnic groups with 15.5% (96), Bugis with 9.7% (60), Brunei with 4.4% (27) and other predominant races with 5.3% (33). Regression analyses revealed that the incidence of CRC in North Borneo, Malaysia, was substantially correlated with income, occupation, other linked diseases and BMI.

CONCLUSION

Various risk factors are linked to CRC, based on the findings related to socio-demographic characteristics and BMI. Therefore, to lower the nationwide prevalence of CRC, national public health campaigns should include collaboration with the regional authorities to highlight the incidence and risk factors of CRC based on ethnicity.

Tunneling Nanotube: An Enticing Cell-Cell Communication in the Nervous System

The field of neuroscience is rapidly progressing, continuously uncovering new insights and discoveries. Among the areas that have shown immense potential in research, tunneling nanotubes (TNTs) have emerged as a promising subject of study. These minute structures act as conduits for the transfer of cellular materials between cells, representing a mechanism of communication that holds great significance. In particular, the interplay facilitated by TNTs among various cell types within the brain, including neurons, astrocytes, oligodendrocytes, glial cells, and microglia, can be essential for the normal development and optimal functioning of this complex organ. The involvement of TNTs in neurodegenerative disorders, such as Alzheimer's disease, Huntington's disease, and Parkinson's disease, has attracted significant attention. These disorders are characterized by the progressive degeneration of neurons and the subsequent decline in brain function. Studies have predicted that TNTs likely play critical roles in the propagation and spread of pathological factors, contributing to the advancement of these diseases. Thus, there is a growing interest in understanding the precise functions and mechanisms of TNTs within the nervous system. This review article, based on our recent work on Rhes-mediated TNTs, aims to explore the functions of TNTs within the brain and investigate their implications for neurodegenerative diseases. Using the knowledge gained from studying TNTs could offer novel opportunities for designing targeted treatments that can stop the progression of neurodegenerative disorders.

Incidence of cerebrovascular accident following head and neck free tissue transfer surgery

The aim of this study was to determine the incidence of postoperative cerebrovascular accident (CVA) following head and neck free tissue transfer and to identify predictive risk factors. A retrospective audit was performed of patients who underwent head and neck reconstructive surgery at Queen Elizabeth University Hospital between 2009 and 2020. The patient records were analysed to identify those who developed CVA within 30 days after surgery. A total of 1109 patients underwent head and neck free tissue transfer surgery, including 1048 neck dissection procedures. Of these, 78.6% had one or more identified risk factors for perioperative stroke. Five patients (0.45%) developed postoperative CVA. The results showed that CVA correlated to patients with hypercholesterolemia (P = 0.007). This study demonstrates the safety of free tissue transfer. Despite underlying co-morbidities and risk factors, the incidence of CVA is low following surgery and manipulation of the major vasculature of the neck.

Effectiveness of a remote care program in the management of patients with resistant hypertension or multiple medication intolerances

Background

A remote hypertension (HTN) program, designed and implemented at Mass General Brigham (MGB), has demonstrated improved HTN control, reduced need for in-person visits, and increased access to care. The program excluded patients with resistant HTN or multiple intolerances/allergies to guideline-directed therapies, whose blood pressure (BP) is difficult to manage.

Purpose

To develop a more intensive but still remote program (“HTN-Plus”) for patients with resistant HTN or intolerances/allergies to multiple medications, and to assess its effectiveness for BP control.

Methods

From 10/2020 through 11/2021, we identified a subset of hypertensive patients from the total pool of those enrolled in our remote HTN management program, who required more personalized and intensive therapy than the overall remote management program provided. We developed ancillary management for these patients, who included: 1) patients with apparent resistant HTN (ARH), ie with uncontrolled BP despite maximum tolerated doses of at least three anti-HTN medications including a diuretic, and 2) patients with multiple medication intolerances or allergies that precluded appropriate triple therapy or limited dose-optimization. A nurse practitioner provided education and advice on BP measurement technique, lifestyle modifications, and adherence. Evaluation for primary aldosteronism (PA) was undertaken in those with ARH.

Results

We enrolled 3658 patients with uncontrolled HTN, of whom 117 qualified for the HTN-Plus program. The average BP on entry was 143/80 mmHg. 68% had apparent resistant HTN and 32% had multiple medication intolerances/allergies. Among all patients, 30% had incorrect BP-measurement technique upon interview, 10% who were tested for PA had a positive screening test, 56% had a history suggestive of an unmanaged secondary cause, and only 6% admitted imperfect adherence, but urine testing was not done. 74% of patients completed the program meaning they were reachable through the end and did not drop out. Across the program, 72 new medications were started, and 84 medication titrations were made. 50% of patients who enrolled in HTN-plus achieved BP &lt;130/80 mmHg. 22% achieved BP control with education and coaching alone. For patients who completed the program, the average entry and final BPs were 139/78 mmHg and 126/70 mmHg respectively, with an average BP decrease of 13/8 mmHg.

Conclusions

In patients who remain hypertensive despite maximally tolerated guideline-directed medication utilization, our intensified but still entirely remote HTN management program helped patients reach their BP goal through education, coaching, and medication management. Nearly a quarter were able to achieve BP control with education and coaching alone. These results suggest that a significant value of remote care in patients with resistant HTN or medication intolerances/allergies lies in ongoing education and coaching, for which more cost-effective solutions may be considered.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Mass General Brigham as part of quality improvement initiative

Striatal Induction and Spread of the Huntington’s Disease Protein: A Novel Rhes Route

The CAG/CAA expansion encoding polyQ huntingtin (mutant huntingtin [mHTT]) causes Huntington’s disease (HD), which is characterized by atrophy and loss of striatal medium spiny neurons (MSNs), which are preceded by neuropathological alterations in the cortex. Previous studies have shown that mHTT can spread in the brain, but the mechanisms involved in the stereotyped degeneration and dysfunction of the neurons from the striatum to the cortex remain unclear. In this study, we found that the mHTT expression initially restricted in the striatum later spread to the cortical regions in mouse brains. Such transmission was diminished in mice that lacked the striatal-enriched protein Ras-homolog enriched in the striatum (Rhes). Rhes restricted to MSNs was also found in the cortical layers of the brain, indicating a new transmission route for the Rhes protein to the brain. Mechanistically, Rhes promotes such transmission via a direct cell-to-cell contact mediated by tunneling nanotubes (TNTs), the membranous protrusions that enable the transfer of mHTT, Rhes, and other vesicular cargoes. These transmission patterns suggest that Rhes and mHTT are likely co-transported in the brain using TNT-like cell-to-cell contacts. On the basis of these new results, a perspective is presented in this review: Rhes may ignite the mHTT transmission from the striatum that may coincide with HD onset and disease progression through an anatomically connected striato-cortical retrograde route.

The EAN Brain Health Strategy: One Brain, One Life, One Approach

BACKGROUND

Brain health is essential for health, well-being productivity and creativity across the entire life. Its definition goes beyond the absence of disease embracing all cognitive, emotional, behavioural and social functions which are necessary to cope with life situations.

METHODS

The EAN Brain Health Strategy responds to the high and increasing burden of neurological disorders. It aims to develop a non-disease, non-age centred holistic and positive approach ('one brain, one life, one approach') to prevent neurological disorders (e.g., Alzheimer's disease and other dementias, stroke, epilepsy, headache/migraine, Parkinson's disease, multiple sclerosis, sleep disorders, brain cancer) but also to preserve brain health and promote recovery after brain damage.

RESULTS

The pillars of the EAN Brain Health strategy are: 1) Contribute to a global and international Brain Health approach (together with national and subspecialty societies, other medical societies, WHO, WFN, patients' organizations, industry, and other stakeholders); 2) Supporting the 47 European national societies, healthcare and policymakers in the implementation of integrated and people-centred campaigns; 3) Fostering Research (e.g. on prevention of neurological disorders, determinants and assessments of brain health), 4) Promoting Education of students, neurologists, general practitioners, other medical specialists and health professionals, patients, caregivers, and general public; 5) Raising public awareness of neurological disorders and brain health.

CONCLUSIONS

By adopting this 'one brain, one life, one approach' strategy in cooperation with partner societies, international organisations, and policymakers, a significant number of neurological disorders may be prevented while enhancing the overall well-being of individuals by maintaining brain health through the life course.

Rhes protein transits from neuron to neuron and facilitates mutant huntingtin spreading in the brain

Rhes (RASD2) is a thyroid hormone-induced gene that regulates striatal motor activity and promotes neurodegeneration in Huntington disease (HD) and tauopathy. Rhes moves and transports the HD protein, polyglutamine-expanded huntingtin (mHTT), via tunneling nanotube (TNT)-like membranous protrusions between cultured neurons. However, similar intercellular Rhes transportation in the intact brain was unknown. Here, we report that Rhes induces TNT-like protrusions in the striatal medium spiny neurons (MSNs) and transported between dopamine-1 receptor (D1R)-MSNs and D2R-MSNs of intact striatum and organotypic brain slices. Notably, mHTT is robustly transported within the striatum and from the striatum to the cortical areas in the brain, and Rhes deletion diminishes such transport. Moreover, Rhes moves to the cortical regions following restricted expression in the MSNs of the striatum. Thus, Rhes is a first striatum-enriched protein demonstrated to move and transport mHTT between neurons and brain regions, providing new insights into interneuronal protein transport in the brain.

Deletion of SUMO1 attenuates behavioral and anatomical deficits by regulating autophagic activities in Huntington disease

The CAG expansion of huntingtin (mHTT) associated with Huntington disease (HD) is a ubiquitously expressed gene, yet it prominently damages the striatum and cortex, followed by widespread peripheral defects as the disease progresses. However, the underlying mechanisms of neuronal vulnerability are unclear. Previous studies have shown that SUMO1 (small ubiquitin-like modifier-1) modification of mHtt promotes cellular toxicity, but the in vivo role and functions of SUMO1 in HD pathogenesis are unclear. Here, we report that SUMO1 deletion in Q175DN HD-het knockin mice (HD mice) prevented age-dependent HD-like motor and neurological impairments and suppressed the striatal atrophy and inflammatory response. SUMO1 deletion caused a drastic reduction in soluble mHtt levels and nuclear and extracellular mHtt inclusions while increasing cytoplasmic mHtt inclusions in the striatum of HD mice. SUMO1 deletion promoted autophagic activity, characterized by augmented interactions between mHtt inclusions and a lysosomal marker (LAMP1), increased LC3B- and LAMP1 interaction, and decreased interaction of sequestosome-1 (p62) and LAMP1 in DARPP-32-positive medium spiny neurons in HD mice. Depletion of SUMO1 in an HD cell model also diminished the mHtt levels and enhanced autophagy flux. In addition, the SUMOylation inhibitor ginkgolic acid strongly enhanced autophagy and diminished mHTT levels in human HD fibroblasts. These results indicate that SUMO is a critical therapeutic target in HD and that blocking SUMO may ameliorate HD pathogenesis by regulating autophagy activities.

A case of an upper anterior abdominal wall extra-skeletal Ewing sarcoma- soft tissue reconstruction with medial intercostal artery perforator flap and free anterolateral thigh fasciocutaneous flap with arteriovenous loop graft

INTRODUCTION

Extra-skeletal Ewing sarcoma - a rare clinical entity. After the tumour resection, a huge upper anterior abdominal wall defect poses a challenge in soft tissue reconstruction in a thin individual.

CASE PRESENTATION

We report an anterior abdominal wall Ewing sarcoma in a 22-year-old gentleman, arising from the left rectus abdominis muscle. After wide local excision, the reconstruction was achieved with free anterolateral thigh(ALT) fasciocutaneous flap with arteriovenous(AV) loop graft, right medial intercostal artery perforator(MICAP) flap and split-thickness skin graft(SSG).

DISCUSSION

The goals of anterior abdominal wall reconstruction are to restore the integrity of the abdominal wall, prevent visceral eventration, and provide functional support. In view of the size of the defect, a free ALT flap was harvested and anastomosed to the left deep inferior epigastric bundle with the AV loop graft. Although the current trend is skewed towards the use of biologic mesh, an on-lay prolene mesh was used due to its affordable cost and that the biologic mesh was not available in Malaysia. The options of further reconstruction after the patient developed marginal flap necrosis and surgical site infection were also discussed. Post-operation 3 months, there was denser hair growth on the ALT flap. This finding has never been reported before and warrants further studies.

CONCLUSION

The use of combination of various technique, namely free ALT fasciocutaneous flap with AV loop graft, right MICAP flap and SSG in reconstruction ensures a satisfactory functional and aesthetic outcome in the upper anterior abdominal wall reconstruction.

Global Rhes knockout in the Q175 Huntington's disease mouse model

Huntington’s disease (HD) results from an expansion mutation in the polyglutamine tract in huntingtin. Although huntingtin is ubiquitously expressed in the body, the striatum suffers the most severe pathology. Rhes is a Ras-related small GTP-binding protein highly expressed in the striatum that has been reported to modulate mTOR and sumoylation of mutant huntingtin to alter HD mouse model pathogenesis. Reports have varied on whether Rhes reduction is desirable for HD. Here we characterize multiple behavioral and molecular endpoints in the Q175 HD mouse model with genetic Rhes knockout (KO). Genetic RhesKO in the Q175 female mouse resulted in both subtle attenuation of Q175 phenotypic features, and detrimental effects on other kinematic features. The Q175 females exhibited measurable pathogenic deficits, as measured by MRI, MRS and DARPP32, however, RhesKO had no effect on these readouts. Additionally, RhesKO in Q175 mixed gender mice deficits did not affect mTOR signaling, autophagy or mutant huntingtin levels. We conclude that global RhesKO does not substantially ameliorate or exacerbate HD mouse phenotypes in Q175 mice.

Applying the British Association of Oral and Maxillofacial Surgeons quality outcomes metrics to a UK oncology and reconstructive surgery service - benchmarking the data

The British Association of Oral and Maxillofacial Surgery is soon to implement the Quality Outcomes in Oral in Maxillofacial Surgery (QOMS) to provide a platform for quality management across the specialty in the UK. The initial oncology and reconstruction audits for QOMS involves data collection on specific procedures and metrics. The aim of this report is to determine their appropriateness using extant audit datasets in our institution that overlap substantially with the QOMS audits. Pre-existing datasets comprising information on patients treated for oral cavity SCC with curative intent were analysed. Data on surgical margins, lymphadenectomy lymph node yield, delay between surgery and adjuvant radiotherapy, duration of hospital stay, and complications including flap failures were analysed. All statistical analyses were performed with SPSS 25. Run charts describing longitudinal data were generated using SPC for Excel version 6. Twenty three patients (3.1%) of 701 resections had a positive surgical margin reported. Seventeen (4.3%) of patients had less than 18 LNs in the ND specimen analysed. Mean time to start date of adjuvant therapy was 62 days. Only 9% of patients commenced adjuvant therapy within 6 weeks. The median duration of stay was 18 days. In 1153 free flaps a failure rate of 4.3% was identified. A total of 1349 complications (CD I-V) were recorded in the 1111 patients undergoing major surgery with free flap reconstruction. The QOMS selected metrics for oncology and reconstruction are clinically relevant, readily measurable, and likely to be actionable by the surgical team.

Ribosome traffic jam in neurodegeneration: decoding hurdles in Huntington disease

A ribosome typically moves at a particular rate on a given mRNA transcript to decode the nucleic acid information required to synthesize proteins. The speed and directionality of the ribosome movements during mRNA translation are determined by the mRNA sequence and structure and by various decoding factors. However, the molecular mechanisms of this remarkable movement during protein synthesis, or its relevance in brain disorders, remain unknown. Recent studies have indicated that defects in protein synthesis occur in various neurodegenerative diseases, but the mechanistic details are unclear. This is a major problem because identifying the factors that determine protein synthesis defects may offer new avenues for developing therapeutic remedies for currently incurable diseases like neurodegenerative disorders. Based on our recent study (Eshraghi et al., Nat Commun 12(1):1461; doi: 10.1038/s41467-021-21637-y), this short commentary will review the mechanistic understanding of Huntingtin (HTT)-mediated ribosome stalling indicating that central defects in protein synthesis in Huntington disease (HD) are orchestrated by jamming of ribosomes on mRNA transcripts.

Mutant Huntingtin stalls ribosomes and represses protein synthesis in a cellular model of Huntington disease

The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.

Temporal mechanisms of myogenic specification in human induced pluripotent stem cells

Understanding the mechanisms of myogenesis in human induced pluripotent stem cells (hiPSCs) is a prerequisite to achieving patient-specific therapy for diseases of skeletal muscle. hiPSCs of different origin show distinctive kinetics and ability to differentiate into myocytes. To address the unique cellular and temporal context of hiPSC differentiation, we perform a longitudinal comparison of the transcriptomic profiles of three hiPSC lines that display differential myogenic specification, one robust and two blunted. We detail temporal differences in mechanisms that lead to robust myogenic specification. We show gene expression signatures of putative cell subpopulations and extracellular matrix components that may support myogenesis. Furthermore, we show that targeted knockdown of ZIC3 at the outset of differentiation leads to improved myogenic specification in blunted hiPSC lines. Our study suggests that β-catenin transcriptional cofactors mediate cross-talk between multiple cellular processes and exogenous cues to facilitate specification of hiPSCs to mesoderm lineage, leading to robust myogenesis.

Operative tactics in floor of mouth and tongue cancer resection - the importance of imaging and planning

Complete tumour resection (R0 margin) is an axiom of surgical oncology. Oral cancer ablation is challenging, due to anatomical, functional, and aesthetic considerations. R0 margin is strongly linked to better survival outcomes with great variation in the R0 % across units. This is commonly attributed to disease biology. Without disputing the importance of biological characteristics, we contend that image-based anatomical surgical planning has an important role to play in achieving complete resection. Here, we present our approach utilising cross-sectional imaging, anatomical characteristics and spatial awareness in planning resections for floor of mouth (FOM) and oral tongue cancers. We highlight the challenge of controlling the deep tumour margin lingual to mandible due to anterior vector constraints and emphasise the importance of resecting the genial muscles in a planned fashion and that any rim resection should be obliquely sagittal. In resecting lateral FOM tumours, assessing extension to the parapharyngeal fat is crucial; and mandibular rim resection at a sagittal plane below the mylohyoid line is often required. Assessing the proximity of the contralateral neurovascular pedicle, pre-epiglottic space and hyoid bone are crucial parameters to determine the extent of tongue tumour resection. Our cohort included 173 patients with FOM SCC and 299 patients with tongue SCC. Six patients (3.5%) from the FOM group and eight patients (3%) from the tongue group had involved (R1) margins following surgery. This was associated with local relapse (p<0.05). In conclusion, we demonstrate that image-based planning can aid achieving R0 resections and reduce disease relapse.

The mammalian target of rapamycin (mTOR) kinase mediates haloperidol-induced cataleptic behavior

The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine/threonine kinase protein complex (mTORC1 or mTORC2) that orchestrates diverse functions ranging from embryonic development to aging. However, its brain tissue-specific roles remain less explored. Here, we have identified that the depletion of the mTOR gene in the mice striatum completely prevented the extrapyramidal motor side effects (catalepsy) induced by the dopamine 2 receptor (D2R) antagonist haloperidol, which is the most widely used typical antipsychotic drug. Conversely, a lack of striatal mTOR in mice did not affect catalepsy triggered by the dopamine 1 receptor (D1R) antagonist SCH23390. Along with the lack of cataleptic effects, the administration of haloperidol in mTOR mutants failed to increase striatal phosphorylation levels of ribosomal protein pS6 (S235/236) as seen in control animals. To confirm the observations of the genetic approach, we used a pharmacological method and determined that the mTORC1 inhibitor rapamycin has a profound influence upon post-synaptic D2R-dependent functions. We consistently found that pretreatment with rapamycin entirely prevented (in a time-dependent manner) the haloperidol-induced catalepsy, and pS6K (T389) and pS6 (S235/236) signaling upregulation, in wild-type mice. Collectively, our data indicate that striatal mTORC1 blockade may offer therapeutic benefits with regard to the prevention of D2R-dependent extrapyramidal motor side effects of haloperidol in psychiatric illness.

Identification of Botryosphaeriaceae associated with stem-end rot of mango (Mangifera indica L.) in Malaysia

AIMS

To identify Botryosphaeriaceae fungal species that are associated with stem-end rot of mango, and to study their pathogenicity on mango fruit.

METHODS AND RESULTS

Based on the sequences of internal transcribed spacer (ITS), TEF1-α and β-tubulin, as well as on the phylogenetic analysis of combined sequences, four species of Lasiodiplodia (L. theobromae,L. pseudotheobromae, L. iranensis, L. mahajangana) and two species of Neofusicoccum (N. ribis, N. parvum) were identified. Pseudofusicoccum violaceum, Neoscytalidium dimidiatum and three species of Botryosphaeria (B. scharifii, B. dothidea, B. ramosa) were identified based on sequences of ITS and TEF1-α. Pathogenicity test of selected isolates were tested on Chok Anan, Waterlily and Falan mango cultivars. Generally, all species were observed to be pathogenic on the three tested mango cultivars on wounded fruits, except for N. ribis and N. parvum, which were pathogenic on both wounded and unwounded fruits. However, N. ribis was only pathogenic on cultivar Falan, whereas B. ramosa were pathogenic on cultivars Waterlily and Falan.

CONCLUSIONS

Eleven species of Botryosphaeriaceae were associated with mango stem-end rot in Malaysia. To the best of our knowledge, four species, namely L. mahajangana, B. ramosa, N. ribis and P. violaceum are the first recorded Botryosphaeriaceae fungi associated with stem end rot of mango.

SIGNIFICANCE AND IMPACT OF THE STUDY

The identification of Botryosphaeriaceae fungi is important to establish suitable control measures and quarantine requirements. Many species have a wide host range, which means that there is a possibility of cross infection from other infected plants.

Rhes Tunnels: A Radical New Way of Communication in the Brain's Striatum?

Ras homolog enriched in the striatum (Rhes) is a striatal enriched protein that promotes the formation of thin membranous tubes resembling tunneling nanotubes (TNT)-"Rhes tunnels"-that connect neighboring cell and transport cargoes: vesicles and proteins between the neuronal cells. Here the literature on TNT-like structures is reviewed, and the implications of Rhes-mediated TNT, the mechanisms of its formation, and its potential in novel cell-to-cell communication in regulating striatal biology and disease are emphasized. Thought-provoking ideas regarding how Rhes-mediated TNT, if it exists, in vivo, would radically change the way neurons communicate in the brain are discussed.

RasGRP1 is a causal factor in the development of l-DOPA-induced dyskinesia in Parkinson's disease

The therapeutic effects of l-3,4-dihydroxyphenylalanine (l-DOPA) in patients with Parkinson's disease (PD) severely diminishes with the onset of abnormal involuntary movement, l-DOPA-induced dyskinesia (LID). However, the molecular mechanisms that promote LID remain unclear. Here, we demonstrated that RasGRP1 [(guanine nucleotide exchange factor (GEF)] controls the development of LID. l-DOPA treatment rapidly up-regulated RasGRP1 in the striatum of mouse and macaque model of PD. The lack of RasGRP1 in mice (RasGRP1^-/- ) dramatically diminished LID without interfering with the therapeutic effects of l-DOPA. Besides acting as a GEF for Ras homolog enriched in the brain (Rheb), the activator of the mammalian target of rapamycin kinase (mTOR), RasGRP1 promotes l-DOPA-induced extracellular signal-regulated kinase (ERK) and the mTOR signaling in the striatum. High-resolution tandem mass spectrometry analysis revealed multiple RasGRP1 downstream targets linked to LID vulnerability. Collectively, the study demonstrated that RasGRP1 is a critical striatal regulator of LID.

Exaggerated mitophagy: a weapon of striatal destruction in the brain?

Mechanisms responsible for neuronal vulnerability in the brain remain unclear. Striatal neurons are preferentially damaged by 3-nitropropionic acid (3-NP), a mitochondrial complex-II inhibitor, causing striatal damage reminiscent of Huntington's disease (HD), but the mechanisms of the selectivity are not as well understood. We have discovered that Rhes, a protein enriched in the striatum, removes mitochondria via the mitophagy process. The process becomes intensified in the presence of 3-NP, thereby eliminating most of the mitochondria from the striatum. We put forward the hypothesis that Rhes acts as a 'mitophagy ligand' in the brain and promotes mitophagy via NIX, a mitophagy receptor. Since Rhes interacts and promotes toxicity in association with mutant huntingtin (mHTT), the genetic cause of HD, it is tempting to speculate on whether the exaggerated mitophagy may be a contributing factor to the striatal lesion found in HD. Thus, Rhes-mediated exaggerated mitophagy may act as a weapon of striatal destruction in the brain.

Selective Neuronal Death in Neurodegenerative Diseases: The Ongoing Mystery

A major unresolved problem in neurodegenerative disease is why and how a specific set of neurons in the brain are highly vulnerable to neuronal death. Multiple pathways and mechanisms have been proposed to play a role in Alzheimer disease (AD), Parkinson disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington disease (HD), yet how they contribute to neuronal vulnerability remains far from clear. In this review, various mechanisms ascribed in AD, PD, ALS, and HD will be briefly summarized. Particular focus will be placed on Rhes-mediated intercellular transport of the HD protein and its role in mitophagy, in which I will discuss some intriguing observations that I apply to model striatal vulnerability in HD. I may have unintentionally missed referring some studies in this review, and I extend my apologies to the authors in those circumstances.

Endoscopic Resections in Inflammatory Bowel Disease: A Multicentre European Outcomes Study

BACKGROUND AND AIMS

Inflammatory bowel disease is associated with an increased risk of colorectal cancer, with estimates ranging 2-18%, depending on the duration of colitis. The management of neoplasia in colitis remains controversial. Current guidelines recommend endoscopic resection if the lesion is clearly visible with distinct margins. Colectomy is recommended if complete endoscopic resection is not guaranteed. We aimed to assess the outcomes of all neoplastic endoscopic resections in inflammatory bowel disease.

METHODS

This was a multicentre retrospective cohort study of 119 lesions of visible dysplasia in 93 patients, resected endoscopically in inflammatory bowel disease.

RESULTS

A total of 6/65 [9.2%] lesions <20 mm in size were treated by ESD [endoscopic submucosal dissection] compared with 59/65 [90.8%] lesions <20 mm treated by EMR [endoscopic mucosal resection]; 16/51 [31.4%] lesions >20 mm in size were treated by EMR vs 35/51 [68.6%] by ESD. Almost all patients [97%] without fibrosis were treated by EMR, and patients with fibrosis were treated by ESD [87%], p < 0.001. In all, 49/78 [63%] lesions treated by EMR were resected en-bloc and 27/41 [65.9%] of the ESD/KAR [knife-assisted resection] cases were resected en-bloc, compared with 15/41 [36.6%] resected piecemeal. Seven recurrences occurred in the cohort. Seven complications occurred in the cohort; six were managed endoscopically and one patient with a delayed perforation underwent surgery.

CONCLUSIONS

Larger lesions with fibrosis are best treated by ESD, whereas smaller lesions without fibrosis are best managed by EMR. Both EMR and ESD are feasible in the management of endoscopic resections in colitis.

Rhes travels from cell to cell and transports Huntington disease protein via TNT-like protrusion

Tunneling nanotubes (TNT) are membranous tubes that connect two cells, but their functional roles and mechanism of biogenesis remain obscure. Sharma and Subramaniam demonstrate that Rhes, a brain-enriched protein, increases biogenesis of TNT-like cellular protrusions or “Rhes tunnels” through which Rhes travels from cell to cell and transports Huntington disease (HD) protein.

Tunneling nanotubes (TNT) are thin, membranous, tunnel-like cell-to-cell connections, but the mechanisms underlying their biogenesis or functional role remains obscure. Here, we report, Rhes, a brain-enriched GTPase/SUMO E3-like protein, induces the biogenesis of TNT-like cellular protrusions, “Rhes tunnels,” through which Rhes moves from cell to cell and transports Huntington disease (HD) protein, the poly-Q expanded mutant Huntingtin (mHTT). The formation of TNT-like Rhes tunnels requires the Rhes’s serine 33, C-terminal CAAX, and a SUMO E3-like domain. Electron microscopy analysis revealed that TNT-like Rhes tunnels appear continuous, cell–cell connections, and <200 nm in diameter. Live-cell imaging shows that Rhes tunnels establish contact with the neighboring cell and deliver Rhes-positive cargoes, which travel across the plasma membrane of the neighboring cell before entering it. The Rhes tunnels carry Rab5a/Lyso 20-positive vesicles and transport mHTT, but not normal HTT, mTOR, or wtTau proteins. SUMOylation-defective mHTT, Rhes C263S (cannot SUMOylate mHTT), or CRISPR/Cas9-mediated depletion of three isoforms of SUMO diminishes Rhes-mediated mHTT transport. Thus, Rhes promotes the biogenesis of TNT-like cellular protrusions and facilitates the cell–cell transport of mHTT involving SUMO-mediated mechanisms.

Employment Challenges Faced by Breast Cancer Survivors in an Upper Middle–Income Asian Setting

Background: Cancer survivorship as an area, which focuses on the health and life of an individual following cancer diagnosis and treatment is increasingly being recognized as an important component of the cancer control continuum. Advances in breast cancer detection and treatments have resulted in a growing number of patients experiencing a breast cancer diagnosis at an age when career plays an important role in their lives. Yet, very little is known on how breast cancer affects employment and return to work among survivors, particularly in low- and middle-income settings. Aim: This qualitative study aims to gain an in-depth understanding on employment challenges and motivators/barriers in return to work faced by breast cancer survivors in an upper-middle income Asian setting. Methods: Eleven focus group discussions (FGDs) were conducted with breast cancer survivors representing various ethnicities and socioeconomic backgrounds in Malaysia. Patients diagnosed one to two years prior to the study were recruited from a general public hospital, a public academic hospital and two private hospitals. Data from the FGDs were examined using thematic content analysis from the NVivo software. Results: The major themes relating to impact of cancer diagnosis on employment were “decreased work ability”, “job loss”, “long absenteeism” and “hostile work environment”. Coping strategy themes frequently mentioned to offset income loss from employment changes were “savings”, “part-time work” or financial support from “family/friends” or “social security”. However, participants were quick to highlight the insufficiency and unreliability of these strategies to cope financially in the long run. When describing their decision in choosing to return to work, participants mentioned themes such as “need money”, feeling “more happy” or having a “supportive work environment”. Nonetheless, participants emphasized the “discrimination” they faced in finding a job after active treatment. Specifically, participants' frequent need to take time-off from work for their cancer follow-ups as well as their older age were perceived as disadvantages in seeking employment when compared with younger, healthy applicants. Conclusion: It is evident that a breast cancer diagnosis severely disrupts employment and return to work in middle income settings. Multisectoral interventions are urgently required to improve the employment status of our cancer survivors, including legislative reforms to prevent discrimination. Programs supporting employment and return to work among cancer survivors should be developed and integrated in the provision of a holistic survivorship care.

Patterns of Complementary and Alternative Medicine Use Following a Cancer Diagnosis in Malaysia

Background: Worldwide surveys suggest that the use of CAM is becoming increasingly popular among the general population as well as among cancer patients. Aim: We determined the patterns of complementary and alternative medicine (CAM) use in cancer patients, and the associated factors in a multiethnic Asian setting. Methods: Through the Asean CosTs In ONcology (ACTION) prospective cohort study, 1662 newly diagnosed cancer patients were recruited from 12 public and 2 private hospitals in Malaysia. In the current study, we only included 1328 patients who were alive and completed one-year of follow-up. Using questionnaires and cost diaries, patients' sociodemographic factors and disease related factors were measured at baseline, whereas details on CAM use were measured at 12 months. Results: Median age at cancer diagnosis was 53 years. Patients comprised those with breast cancer (33%), gastrointestinal cancers (27%), hematologic malignancies (22%), female reproductive cancers (6%), respiratory cancers (5%), and other types. At one-year, 175 patients reported using CAM (14%), of which 53 comprised patients reporting inability to make necessary household payments (economic hardship) at initial diagnosis. Most CAM users took food or nutritional supplements (75%), spending between RM150 to RM7500 in a year, followed by traditional local medicine (43%), where expenditures ranged between RM50 to RM20,000. A minority practiced homeopathy, and mind-body practices. Fifty-one patients used more than one type of therapy. In CAM users with economic hardship at baseline, median expenditure on CAM was RM1500, with some spending as much as RM10,000. Compared with other cancer types, patients with hematologic malignancies and women with breast cancer were most likely to use CAM. In a multivariable analysis, baseline factors that were associated with CAM use were economic hardship, higher anxiety scores, having female reproductive cancers, or hematologic malignancies, receipt of surgery, and nonreceipt of radiotherapy. Sex, education status, marital status, health insurance status, cancer stage, and systemic cancer therapy do not appear to be associated with CAM use. Conclusion: While the proportion of patients reporting CAM use following a cancer diagnosis appear low in this study, the finding that patients with initial economic hardship were independently more likely to use CAM, warrants attention.

Effect of Sudarshan Kriya Pranayama on periodontal status and human salivary beta-defensin-2: An interventional study

BACKGROUND

Yogic stretching (asana) has been proven to have an effect on salivary human beta-defensin-2 (HBD-2) concentration, which is an antimicrobial peptide and is an inflammatory marker in periodontal disease. Sudarshan Kriya Pranayama (SKP) is a part of yoga which involves rhythmic breathing. Hence, we aim to evaluate the periodontal parameters and to estimate the salivary HBD-2 level before and after SKP program in periodontitis individuals.

MATERIALS AND METHODS

An interventional study was designed and individuals were divided into three groups: Group I - healthy periodontium, Group II - chronic gingivitis, and Group III - chronic periodontitis. SKP was the interventional tool. The clinical parameters such as plaque index (PI), gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL), and salivary HBD-2 level were analyzed at baseline and 90 days after the SKP practice. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate salivary HBD-2. McNemar's Chi-square, Paired samples t-test, and one-way ANOVA were used to analyze the results. P < 0.05 was considered statistically significant.

RESULTS

Following the SKP intervention, the clinical parameters such as PI and GI improved significantly in all the groups (P < 0.001); however, Group III showed a significant reduction as compared to the other groups. The mean baseline salivary HBD-2 levels of Group I, Group II, and Group III were 91.78 ng/μl, 110.22 ng/μl, and 157.63 ng/μl which was further decreased to 95.22 ng/μl, 98.22 ng/μl, and 132.88 ng/μl, respectively, following SKP intervention (P < 0.001). However, Group III had a higher HBD-2 level at 90 th day as compared to other groups.

CONCLUSION

There was an improvement in PI and GI with a decrease in salivary HBD-2 in chronic periodontitis patients following SKP. Hence, SKP can be considered as an adjunct to treatment modality in patients with periodontal disease.

A comparison of intraoperative haemostatic techniques during tonsillectomy: Suture vs electrocautery-A study to assess postoperative pain scores and duration to resumption of normal diet

OBJECTIVES

To assess postoperative pain and pattern of recovery to normal diet in children who underwent tonsillectomy.

METHODS

Cold steel tonsillectomy (or adenotonsillectomy) was performed in 61 children. Haemostasis was attained with sutures in Group 1 (n = 30, 8 tonsillectomy and 22 adenotonsillectomy), and electrocautery in Group 2 (n = 31, 6 tonsillectomy and 25 adenotonsillectomy). Information obtained included postoperative pain scores and the number of postoperative days taken to resume normal diet. The pain score was evaluated with the Wong-Baker FACES^® Pain Rating Scale (WBFS).

RESULTS

Pain values in Group 1 (haemostasis with sutures) were significantly lower than those in Group 2 (haemostasis with cauterisation) from the 6th hour to the 7th postoperative day (P < .05). For both liquid and solid food, Group 1 returned to normal diet earlier, compared to Group 2 (P < .05). When comparing patients undergoing tonsillectomy vs adenotonsillectomy, resumption of normal diet was achieved later in the adenotonsillectomy patients (P < .05). In terms of postoperative bleeding, there were 2 significant events in Group 2 (electrocautery group), occurring on the 1st (severe) and 10th day (slight) in 2 children (6.5%). There were no postoperative bleeding events in Group 1.

CONCLUSION

Our results showed that suture haemostatis causes less pain and faster resumption of normal diet compared to electrocautery. In view of this, we recommend the use of sutures for achieving intraoperative haemostasis in paediatric patients.

The safety and efficacy of radiofrequency ablation following endoscopic submucosal dissection for Barrett's neoplasia

The current standard of treating early Barrett's neoplasia is resection of visible lesions using endoscopic mucosal resection (EMR) followed by ablative therapy to the Barrett's segment. There is increasing evidence to support the use of endoscopic submucosal dissection (ESD) where en-bloc resection and lower recurrence rates may be achieved. However, ESD is associated with deep submucosal dissection when compared to EMR. This may increase the risk of complications including stricture formation with subsequent radiofrequency ablation (RFA) therapy. The aim of this study is to compare the safety and efficacy of RFA following EMR and ESD as well as when RFA was used without prior endoscopic resection. The primary outcome measure was complication rates. Clearance of dysplasia (CRD) and clearance of intestinal metaplasia (CRIM) were secondary outcomes. A retrospective analysis of a cohort of 91 patients referred for RFA from a single academic tertiary center was performed. The choice of endoscopic resection method was tailored according to the lesion type and morphology. Focal and circumferential ablation was performed after initial follow up endoscopy postresection. Patients proceeded straight to RFA in the absence of any visible lesions. In this study, the ESD group had a higher proportion of cancers compared to the EMR cohort (74.1% vs. 30.2%, P < 0.01) prior to RFA. All complications post RFA occurred in the groups with previous endoscopic resection. There was no significant difference in the total complication rate (7.4% vs. 9.3%, P = 0.78) and stricture formation rate (3.7% vs. 9.3%, P = 0.38) between the ESD and EMR groups. CRD was achieved in 96.3% in the ESD group, 88.4% in the EMR group, and all patients in the RFA alone group. CRIM rates were similar in the EMR and ESD groups (81.4% vs. 85.2%) but higher in the RFA alone group (90.5%). In conclusion, RFA following ESD is very effective and not associated with an increased risk of complications compared to EMR. This supports the application of RFA in the treatment algorithm of patients undergoing ESD for Barrett's neoplasia.

Dynamics of widespread foot-and-mouth disease virus serotypes A, O and Asia-1 in southern Asia: A Bayesian phylogenetic perspective

Foot-and-mouth disease (FMD) is, arguably, the animal disease with the most devastating global economic impact owing in part, to the severe trade restrictions imposed upon affected countries and regions. South Asia is one of the regions where widespread lineages of the FMDV virus (FMDV) have emerged. Here, we performed an integrative phylogenetic analysis of all FMDV serotypes (A, O and Asia-1) circulating in southern Asia, including viral sequences collected until 2013. Our results describe the occurrence of FMD caused by different serotypes and lineages, focusing in the cycles where a specific lineage predominates within a region for a protracted period and then are rapidly or progressively replaced by an emergent or re-emergent strain that is introduced from an adjacent region. Transmission between the two main regions in southern Asia (the Indian subcontinent and the region comprised by Afghanistan, Iran and Pakistan) has been limited. Results of time divergence estimation of lineages that currently circulate in this region indicate that the most recent common ancestor of endemic lineages are: 1992 [1989-1995] for lineage O/PanAsia; 1997 [1995-1999] for PanAsia2; 2001 [1998-2004] for O/Ind2001; 2001 [2000-2002] for A/Iran-05; 1990 [1988-1991] for A/G-18 (G-VII); 2003 [2000-2006] for Asia-1 Sindh08 and 2002 [1999-2004] for Asia-1 G-VIII. We estimated the mean of the overall substitution rate of the VP1 coding region (substitution/site/year) for serotype O (5.95 × 10^-3 ), serotype A (1.19 × 10^-2 ) and serotype Asia-1 (3.08 × 10^-3 ). The potential factors driving the lineage turnover are discussed. Our results provide insights into the ecological and evolutionary factors driving the emergence of FMDV.

Foot-and-mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

Foot-and-mouth disease (FMD) is an important transboundary disease with substantial economic impacts. Although between-herd transmission of the disease has been well studied, studies focusing on within-herd transmission using farm-level outbreak data are rare. The aim of this study was to estimate parameters associated with within-herd transmission, host physiological factors and FMD virus (FMDV) persistence using data collected from an outbreak that occurred at a large, organized dairy farm in India. Of 1,836 regularly vaccinated, adult dairy cattle, 222 had clinical signs of FMD over a 39-day period. Assuming homogenous mixing, a frequency-dependent compartmental model of disease transmission was built. The transmission coefficient and basic reproductive number were estimated to be between 16.2-18.4 and 67-88, respectively. Non-pregnant animals were more likely to manifest clinical signs of FMD as compared to pregnant cattle. Based on oropharyngeal fluid (probang) sampling and FMDV-specific RT-PCR, four of 36 longitudinally sampled animals (14%) were persistently infected carriers 10.5 months post-outbreak. There was no statistical difference between subclinical and clinically infected animals in the duration of the carrier state. However, prevalence of NSP-ELISA antibodies differed significantly between subclinical and clinically infected animals 12 months after the outbreak with 83% seroprevalence amongst clinically infected cattle compared to 69% of subclinical animals. This study further elucidates within-herd FMD transmission dynamics during the acute-phase and characterizes duration of FMDV persistence and seroprevalence of FMD under natural conditions in an endemic setting.