POT1 and multiple primary melanomas: the dermatological phenotype.

POT1 is the second most frequently reported gene (after CDKN2A) in familial melanoma. Pathogenic variants are associated with earlier onset and/or multiple primary melanomas (MPMs). To date, POT1 phenotypical reports have been largely restricted to associated malignancies, and description of the dermatological landscape has been limited. We identified 10 variants in n=18 of 384 (4.7%) unrelated individuals (n=13 MPMs; n=5 single primary melanomas) of European ancestry. Five variants were rare (minor allele frequency <0.001) or novel (two loss-of-function (LOF), one splice acceptor and two missense) and were predicted to be functionally significant, in five unrelated probands with MPMs (≥3 melanomas). We performed three-dimensional total body photography on both individuals with confirmed pathogenic LOF variants to characterise the dermatological phenotype. Total body naevus counts (≥2 mm diameter) were significantly higher (p=7.72×10-12) in carriers compared with a control population. Majority of naevi were on the probands' back and lower limb regions, where only mild to moderate ultraviolet (UV) damage was observed. Conversely, the head/neck region, where both probands exhibited severe UV damage, had comparably fewer naevi. We hypothesise that carriage of functionally significant POT1 variants is associated with increased naevus counts generally, and naevi >5 mm in diameter specifically and the location of these are independent of UV damage.

Identification of equine mares as reservoir hosts for pathogenic species of Leptospira.

Equine leptospirosis can result in abortion, stillbirth, neonatal death, placentitis, and uveitis. Horses can also act as subclinical reservoir hosts of infection, which are characterized as asymptomatic carriers that persistently excrete leptospires and transmit disease. In this study, PCR and culture were used to assess urinary shedding of pathogenic Leptospira from 37 asymptomatic mares. Three asymptomatic mares, designated as H2, H8, and H9, were PCR-positive for lipL32, a gene specific for pathogenic species of Leptospira. One asymptomatic mare, H9, was culture-positive, and the recovered isolate was classified as L. kirschneri serogroup Australis serovar Rushan. DNA capture and enrichment of Leptospira genomic DNA from PCR-positive, culture-negative samples determined that asymptomatic mare H8 was also shedding L. kirschneri serogroup Australis, whereas asymptomatic mare H2 was shedding L. interrogans serogroup Icterohaemorrhagiae. Sera from all asymptomatic mares were tested by the microscopic agglutination test (MAT) and 35 of 37 (94.6%) were seropositive with titers ranging from 1:100 to 1:3200. In contrast to asymptomatic mares, mare H44 presented with acute spontaneous abortion and a serum MAT titer of 1:102,400 to L. interrogans serogroup Pomona serovar Pomona. Comparison of L. kirschneri serogroup Australis strain H9 with that of L. interrogans serogroup Pomona strain H44 in the hamster model of leptospirosis corroborated differences in virulence of strains. Since lipopolysaccharide (LPS) is a protective antigen in bacterin vaccines, the LPS of strain H9 (associated with subclinical carriage) was compared with strain H44 (associated with spontaneous abortion). This revealed different LPS profiles and immunoreactivity with reference antisera. It is essential to know what species and serovars of Leptospira are circulating in equine populations to design efficacious vaccines and diagnostic tests. Our results demonstrate that horses in the US can act as reservoir hosts of leptospirosis and shed diverse pathogenic Leptospira species via urine. This report also details the detection of L. kirschneri serogroup Australis serovar Rushan, a species and serotype of Leptospira, not previously reported in the US.

Corrigendum: Fecal and vaginal microbiota of vaccinated and non-vaccinated pregnant elk challenged with Brucella abortus.

[This corrects the article DOI: 10.3389/fvets.2024.1334858.].

Minimally Invasive Approaches to Diagnose and Monitor Eosinophilic GI Diseases.

PURPOSE OF REVIEW: This review seeks to understand novel avenues for eosinophilic GI disease management. Biomarkers offer a unique and non-invasive approach to tracking EoE disease progression. While no biomarkers have definitively met the diagnostic criteria for eosinophilic GI diseases, some biomarkers have been shown to be associated with disease activity. Here, we examine the potential of recently studied biomarkers. RECENT FINDINGS: Current research shows advancements in blood, luminal fluid, and breath testing. Particular areas of interest include mRNA analyses, protein fingerprinting, amplicon sequence variants (ASVs), T cells and IgE receptors, eosinophilic cationic proteins, cytokines, and nitric oxide exhalation. Preliminary results showed that mucosal biomarkers, directly captured from the esophagus, may reflect the best representation of biopsy-based results, in contrast to biomarkers obtained from indirect or peripheral (blood, breath) methods. However, this is based on limited clinical studies without sufficient numbers to evaluate true diagnostic accuracy. Large-scale randomized trials are needed to fully ascertain both the optimal sampling technique and the specific biomarkers that reflect diagnostic status of the disease.

Proteomic profiles of Leptospira borgpetersenii serovar Hardjo strains JB197 and HB203 cultured at different temperatures.

Leptospirosis is a global zoonotic disease affecting humans, domestic, and wild animals. Leptospira are typically shed in the urine of reservoir hosts which persist in suitable environments where incidental host transmission occurs after direct contact with infected urine or contaminated environments. Interestingly, serologically identical L. borgpetersenii serovar Hardjo strains JB197 and HB203 show divergent disease severity in the hamster model; JB197 causes severe acute infection while HB203 causes persistent chronic infection. Historically, serovar Hardjo was limited to culture at 29 °C, but utilization of HAN media allows propagation from host tissues at 37 °C. Here, the proteome of strains JB197 and HB203 were characterized after culture from experimentally challenged hamsters at 29 °C and 37 °C. Comparative analyses of JB197 and HB203 samples cultured at 29 °C yielded 425 significantly differentially expressed (DE) proteins, while strains at 37 °C yielded 613 DE proteins including prominent outer membrane proteins and known virulence factors. In agreement, membrane protein GO terms were identified by STRING network analyses along with numerous metabolic KEGG pathways consistent with condition differences. Within strain, JB197 cultured at 29 °C vs 37 °C identified 529 DE proteins, while HB203 identified 524 DE proteins. Investigating differential protein profiles provide insights into strain specific behaviors with implications for better understanding host-pathogen interactions, disease transmission, and response to environmental conditions which can contribute to vaccine development, diagnostic improvement, and ultimately leptospirosis control. SIGNIFICANCE: Leptospirosis is a devastating zoonotic disease affecting humans, wild and domestic animals around the globe. Different species and serovars of Leptospira can affect various animal host species differently; for instance, a serovar that is asymptomatic in the rat may cause severe disease in a dog or human. These differences in host response are not only found at the species and serovar level for Leptospira, but also at the strain level. A prime example comes from strains JB197 and HB203, both species L. borgpetersenii, both serovar Hardjo. Interestingly, JB197 causes a severe acute infection in the hamster while HB203 causes an asymptomatic chronic infection. Understanding these unique relationships between pathogen and host species is important, especially in the context of prevention technologies such as vaccine design, where the strain of Leptospira used as a bacterin might have different efficiencies in different hosts. In this study, proteomic profiles of strains JB197 and HB203 were analyzed, and results revealed diverse protein expression profiles of outer membrane proteins, as well as proteins functioning in motility and growth.

Fecal and vaginal microbiota of vaccinated and non-vaccinated pregnant elk challenged with Brucella abortus.

Introduction: Brucella abortus is the causative agent of brucellosis in cattle and in humans, resulting in economic losses in the agricultural sector and representing a major threat to public health. Elk populations in the American Northwest are reservoirs for this bacterium and transmit the agent to domestic cattle herds. One potential strategy to mitigate the transmission of brucellosis by elk is vaccination of elk populations against B. abortus; however, elk appear to be immunologically distinct from cattle in their responses to current vaccination strategies. The differences in host response to B. abortus between cattle and elk could be attributed to differences between the cattle and elk innate and adaptive immune responses. Because species-specific interactions between the host microbiome and the immune system are also known to affect immunity, we sought to investigate interactions between the elk microbiome and B. abortus infection and vaccination. Methods: We analyzed the fecal and vaginal microbial communities of B. abortus-vaccinated and unvaccinated elk which were challenged with B. abortus during the periparturient period. Results: We observed that the elk fecal and vaginal microbiota are similar to those of other ruminants, and these microbial communities were affected both by time of sampling and by vaccination status. Notably, we observed that taxa representing ruminant reproductive tract pathogens tended to increase in abundance in the elk vaginal microbiome following parturition. Furthermore, many of these taxa differed significantly in abundance depending on vaccination status, indicating that vaccination against B. abortus affects the elk vaginal microbiota with potential implications for animal reproductive health. Discussion: This study is the first to analyze the vaginal microbiota of any species of the genus Cervus and is also the first to assess the effects of B. abortus vaccination and challenge on the vaginal microbiome.

Bacteroides and related species: The keystone taxa of the human gut microbiota.

Microbial communities play a significant role in maintaining ecosystems in a healthy homeostasis. Presently, in the human gastrointestinal tract, there are certain taxonomic groups of importance, though there is no single species that plays a keystone role. Bacteroides spp. are known to be major players in the maintenance of eubiosis in the human gastrointestinal tract. Here we review the critical role that Bacteroides play in the human gut, their potential pathogenic role outside of the gut, and their various methods of adapting to the environment, with a focus on data for B. fragilis and B. thetaiotaomicron. Bacteroides are anaerobic non-sporing Gram negative organisms that are also resistant to bile acids, generally thriving in the gut and having a beneficial relationship with the host. While they are generally commensal organisms, some Bacteroides spp. can be opportunistic pathogens in scenarios of GI disease, trauma, cancer, or GI surgery, and cause infection, most commonly intra-abdominal infection. B. fragilis can develop antimicrobial resistance through multiple mechanisms in large part due to its plasticity and fluid genome. Bacteroidota (formerly, Bacteroidetes) have a very broad metabolic potential in the GI microbiota and can rapidly adapt their carbohydrate metabolism to the available nutrients. Gastrointestinal Bacteroidota species produce short-chain fatty acids such as succinate, acetate, butyrate, and occasionally propionate, as the major end-products, which have wide-ranging and many beneficial influences on the host. Bacteroidota, via bile acid metabolism, also play a role in in colonization-resistance of other organisms, including Clostridioides difficile, and maintenance of gut integrity.

Genetic testing for familial melanoma.

While the average lifetime risk of melanoma worldwide is approximately 3%, those with inherited high-penetrance mutations face an increased lifetime risk of 52-84%. In countries of low melanoma incidence, such as in Southern Europe, familial melanoma genetic testing may be warranted when there are two first degree relatives with a melanoma diagnosis. Testing criteria for high incidence countries such as USA, or with very-high incidence, such as Australia and New Zealand, would require a threshold of 3 to 4 affected family members. A mutation in the most common gene associated with familial melanoma, CDKN2A, is identified in approximately 10-40% of those meeting testing criteria. However, the use of multi-gene panels covering additional less common risk genes can significantly increase the diagnostic yield. Currently, genetic testing for familial melanoma is typically conducted by qualified genetic counsellors, however with increasing demand on testing services and high incidence rate in certain countries, a mainstream model should be considered. With appropriate training, dermatologists are well placed to identify high risk individuals and offer melanoma genetic test in dermatology clinics. Genetic testing should be given in conjunction with pre- and post-test consultation. Informed patient consent should cover possible results, the limitations and implications of testing including inconclusive results, and potential for genetic discrimination. Previous studies reporting on participant outcomes of genetic testing for familial melanoma have found significant improvements in both sun protective behavior and screening frequency in mutation carriers.

MITF E318K: A rare homozygous case with multiple primary melanoma.

MITF E318K moderates melanoma risk. Only five MITF E318K homozygous cases have been reported to date, one in association with melanoma. This novel report uses 3D total-body-photography (TBP) to describe the dermatological phenotype of a homozygous MITF E318K individual. The case, a 32-year-old male, was diagnosed with his first of six primary melanomas at 26 years of age. Five melanomas were located on the back and one in the groin. Two were superficial spreading. Three arose from pre-existing naevi and one was a rare naevoid melanoma. 3D-TBP revealed a high naevus count (n = 162) with pigmentation varying from light to dark. Most naevi generally (n = 90), and large (>5 mm diameter) and clinically atypical naevi specifically were located on the back where sun damage was mild. In contrast, naevi count was low (n = 25 total) on the head/neck and lower limbs where sun damage was severe. Thus, melanoma location correlated with naevi density, rather than degree of sun damage. In addition to the MITF E318K homozygosity, there was heterozygosity for four other moderate-risk variants, which may contribute to melanoma risk. Further research is warranted to explore whether melanomas in E318K heterozygous and other homozygotes coincide with regions of high naevi density as opposed to sun damage. This could inform future melanoma screening/surveillance.

Defects of the spliceosomal gene SNRPB affect osteo- and chondro-differentiation.

Although gene splicing occurs throughout the body, the phenotype of spliceosomal defects is largely limited to specific tissues. Cerebro-costo-mandibular syndrome (CCMS) is one such spliceosomal disease, which presents as congenital skeletal dysmorphism and is caused by mutations of SNRPB gene encoding Small Nuclear Ribonucleoprotein Polypeptides B/B' (SmB/B'). This study employed in vitro cell cultures to monitor osteo- and chondro-differentiation and examined the role of SmB/B' in the differentiation process. We found that low levels of SmB/B' by knockdown or mutations of SNRPB led to suppressed osteodifferentiation in Saos-2 osteoprogenitor-like cells, which was accompanied by affected splicing of Dlx5. On the other hand, low SmB/B' led to promoted chondrogenesis in HEPM mesenchymal stem cells. Consistent with other reports, osteogenesis was promoted by the Wnt/ß-catenin pathway activator and suppressed by Wnt and BMP blockers, whereas chondrogenesis was promoted by Wnt inhibitors. Suppressed osteogenic markers by SNRPB knockdown were partly rescued by Wnt/ß-catenin pathway activation. Reporter analysis revealed that suppression of SNRPB results in attenuated Wnt pathway and/or enhanced BMP pathway activities. SNRPB knockdown altered splicing of TCF7L2 which impacts Wnt/ß-catenin pathway activities. This work helps unravel the mechanism underlying CCMS whereby reduced expression of spliceosomal proteins causes skeletal phenotypes.

Effect of selection genotype on immune response to Brucella abortus RB51 in Holstein cattle.

Genetic selection for milk production traits in US Holsteins has affected numerous genes associated with reproduction and immunity. This study compares the transcriptomic response of peripheral blood mononuclear cells to an in vitro Brucella abortus strain RB51 (RB51) bacterial challenge between contemporary Holsteins and Holsteins that have not been selected for milk production traits since the mid-1960s. Total RNA was extracted from peripheral blood mononuclear cells from four contemporary and four unselected lactating, primiparous cows following 24-h incubation with or without stimulation with RB51 bacteria. RNA was sequenced and reads analyzed using tools from galaxy.scinet.usda.gov. A total of 412 differentially expressed genes (false discovery rate p < 0.05, log fold change > |1|) were identified. The upregulated genes (genes with higher expression in contemporary than unselected cattle) were enriched for 19 terms/pathways, including alanine, aspartate, and glutamate metabolism, indicating a cellular stress response. Downregulated genes (genes with higher expression in unselected than contemporary cows) were enriched for 37 terms/pathways, representing diverse immune responses, including natural killer cell-mediated immunity, interferon-γ production, negative regulation of interleukin-10 production, and cytokine receptor activity indicating a broad immune response with an emphasis on immune defense. These results provide evidence that differences exist between the two genotypes in response to in vitro bacterial challenge. This suggests that contemporary cows, genetically selected for milk production, may have reduced immune function, including limitations in response to intracellular bacteria.

Recommendations to Improve Quality of Probiotic Systematic Reviews With Meta-Analyses.

Importance: Systematic reviews and meta-analyses often report conflicting results when assessing evidence for probiotic efficacy, partially because of the lack of understanding of the unique features of probiotic trials. As a consequence, clinical decisions on the use of probiotics have been confusing. Objective: To provide recommendations to improve the quality and consistency of systematic reviews with meta-analyses on probiotics, so evidence-based clinical decisions can be made with more clarity. Evidence Review: For this consensus statement, an updated literature review was conducted (January 1, 2020, to June 30, 2022) to supplement a previously published 2018 literature search to identify areas where probiotic systematic reviews with meta-analyses might be improved. An expert panel of 21 scientists and physicians with experience on writing and reviewing probiotic reviews and meta-analyses was convened and used a modified Delphi method to develop recommendations for future probiotic reviews. Findings: A total of 206 systematic reviews with meta-analysis components on probiotics were screened and representative examples discussed to determine areas for improvement. The expert panel initially identified 36 items that were inconsistently reported or were considered important to consider in probiotic meta-analyses. Of these, a consensus was reached for 9 recommendations to improve the quality of future probiotic meta-analyses. Conclusions and Relevance: In this study, the expert panel reached a consensus on 9 recommendations that should promote improved reporting of probiotic systematic reviews with meta-analyses and, thereby, assist in clinical decisions regarding the use of probiotics.

Wildlife Immune Responses to Mycobacterium bovis and to Bacille of Calmette-Guerin.

Bovine tuberculosis (bTB) is a zoonotic bacterial disease presenting public health, veterinary, and economic threats around the globe. Although cattle producers rely on regular testing and management practices to minimize domestic herd exposure, wildlife species around the world continue to be the main reservoirs for disease. Wildlife reservoirs for bTB include the Eurasian badger (Meles meles) in Great Britain and Ireland, the brushtail possum (Trichosurus vulpecula) in New Zealand, wild boar (Sus scrofa) in Spain, as well as white-tailed deer (Odocoileus virginianus) in the United States and red deer (Cervus elaphus) in Spain. Although all reservoir species share the ability to infect cattle, they differ in transmission capability, disease pathogenesis, diagnostic detection, and vaccination strategies. In this review, bTB interactions with these wildlife reservoirs are discussed, illustrating the need to address bTB disease in wildlife hosts to achieve eradication in domestic livestock.

Vaccination of White-Tailed Deer with Mycobacterium bovis Bacillus Calmette-Guérin (BCG): Effect of Mycobacterium avium ssp. paratuberculosis Infection.

In many parts of the world, bovine tuberculosis eradication efforts are hampered by wildlife reservoirs of Mycobacterium bovis, which serve as a constant source of M. bovis for nearby cattle. The human tuberculosis vaccine, M. bovis BCG has been investigated for use in several wildlife species, including deer. In the US, white-tailed deer in Michigan have been the source of infection for over 82 cattle herds since M. bovis was discovered in free-ranging deer in 1995. The efficacy of BCG may be influenced by many factors, including prior exposure or infection with non-tuberculous mycobacteria, that is, species other than members of the M. tuberculosis complex. M. avium subspecies paratuberculosis (Map) infection is not uncommon in ruminants such as deer. Using natural exposure to Map and experimental infection with M. bovis, we demonstrate that Map infection increased BCG vaccine efficacy as measured by lesion severity scores.

Assessing and Identifying Improvements for Lung Cancer Screening in a Rural Population: A Human-Centered Design and Systems Approach.

Although lung cancer claims more lives than any other cancer in the United States, screening is severely underutilized, with <6% of eligible patients screened nationally in 2021 versus 76% for breast cancer and 67% for colorectal cancer. This article describes an effort to identify key reasons for the underutilization of lung cancer screening in a rural population and to develop interventions to address these barriers suitable for both a large health system and local community clinics. Data were generated from 26 stakeholder interviews (clinicians, clinical staff, and eligible patients), a review of key systems (Electronic Health Record and billing records), and feedback on the feasibility of several potential interventions by health care system staff. These data informed a human-centered design approach to identify possible interventions within a complex health care system by exposing gaps in care processes and electronic health record platforms that can lead patients to be overlooked for potentially life-saving screening. Deployed interventions included communication efforts focused on (1) increasing patient awareness, (2) improving physician patient identification, and (3) supporting patient management. Preliminary outcomes are discussed.

Developmental genetic underpinnings of a symbiosis-associated organ in the fungus-farming ambrosia beetle Euwallacea validus.

Mutualistic interactions between organisms often mediate the innovation of traits essential to maintain the relationship. Yet our understanding of these interactions has been stymied due to various hurdles in studying the genetics of non-model animals. To understand the genetic mechanisms by which such traits develop, we examined the function of genes breathless (btl), trachealess (trh), and doublesex in the development of a novel fungus-carrying organ (mycangium) that facilitates an obligate relationship between fungus-farming ambrosia beetles and specific fungal partners. Gene knockdown by RNA interference and subsequent micro-computed tomography visualization suggest btl and trh are required for initiation of mycangia and that tubulogenesis may have been co-opted for early mycangial development.

Dock2 generates characteristic spatiotemporal patterns of Rac activity to regulate neutrophil polarisation, migration and phagocytosis.

Introduction: Rac-GTPases and their Rac-GEF activators play important roles in neutrophil-mediated host defence. These proteins control the adhesion molecules and cytoskeletal dynamics required for neutrophil recruitment to inflamed and infected organs, and the neutrophil effector responses that kill pathogens. Methods: Here, we used live cell TIRF-FRET imaging in neutrophils from Rac-FRET reporter mice with deficiencies in the Rac-GEFs Dock2, Tiam1 or Prex1/Vav1 to evaluate if these proteins activate spatiotemporally distinct pools of Rac, and to correlate patterns of Rac activity with the neutrophil responses they control. Results: All the GEFs were required for neutrophil adhesion, and Prex1/Vav1 were important during spreading and for the velocity of migration during chemotaxis. However, Dock2 emerged as the prominent regulator of neutrophil responses, as this GEF was required for neutrophil polarisation and random migration, for migration velocity during chemokinesis, for the likelihood to migrate and for the speed of migration and of turning during chemotaxis, as well as for rapid particle engulfment during phagocytosis. We identified characteristic spatiotemporal patterns of Rac activity generated by Dock2 which correlate with the importance of the Rac-GEF in these neutrophil responses. We also demonstrate a requirement for Dock2 in neutrophil recruitment during aseptic peritonitis. Discussion: Collectively, our data provide a first direct comparison of the pools of Rac activity generated by different types of Rac-GEFs, and identify Dock2 as a key regulator of polarisation, migration and phagocytosis in primary neutrophils.

Microbiome-Related and Infection Control Approaches to Primary and Secondary Prevention of Clostridioides difficile Infections.

Clostridioides difficile infections (CDIs) have decreased in the past years, but since 2021, some hospitals have reported an increase in CDI rates. CDI remains a global concern and has been identified as an urgent threat to healthcare. Although multiple treatment options are available, prevention strategies are more limited. As CDI is an opportunistic infection that arises after the normally protective microbiome has been disrupted, preventive measures aimed at restoring the microbiome have been tested. Our aim is to update the present knowledge on these various preventive strategies published in the past five years (2018-2023) to guide clinicians and healthcare systems on how to best prevent CDI. A literature search was conducted using databases (PubMed, Google Scholar, and clinicaltrials.gov) for phase 2-3 clinical trials for the primary or secondary prevention of CDI and microbiome and probiotics. As the main factor for Clostridium difficile infections is the disruption of the normally protective intestinal microbiome, strategies aimed at restoring the microbiome seem most rational. Some strains of probiotics, the use of fecal microbial therapy, and live biotherapeutic products offer promise to fill this niche; although, more large randomized controlled trials are needed that document the shifts in the microbiome population.

Lactobacillus Bacteremia and Probiotics: A Review.

Lactobacilli are widely found in nature, are commensal microbes in humans, and are commonly used as probiotics. Concerns about probiotic safety have arisen due to reports of bacteremia and other Lactobacillus-associated infections. We reviewed the literature for articles on the pathogenicity of Lactobacillus spp. bacteremia and reports of probiotics in these patients. Our aim is to review these articles and update the present knowledge on the epidemiology of Lactobacillus spp. bacteremia and determine the role of probiotics in Lactobacillus bacteremia. Lactobacillus bacteremia is infrequent but has a higher risk of mortality and risk factors, including severe underlying diseases, immune system suppression, admission to intensive care units, and use of central venous catheters. A variety of Lactobacillus species may cause bacteremia and may or may not be associated with probiotic exposure. To determine if oral probiotics are the source of these infections, the blood isolates and the oral probiotic strain(s) must be compared by sensitive identification methods. The prevalence of Lactobacillus bacteremia is infrequent but is more common in patients taking probiotics compared to those not taking probiotics. Three probiotics (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) were directly linked with blood isolates from bacteremia patients using molecular identification assays.