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Upsala Journal of Medical Sciences 2024The development of bispecific antibodies that can traverse the blood-brain barrier has paved the way for brain-directed immunotherapy and when radiolabelled, immunoPET...
BACKGROUND
The development of bispecific antibodies that can traverse the blood-brain barrier has paved the way for brain-directed immunotherapy and when radiolabelled, immunoPET imaging. The objective of this study was to investigate how indium-111 (In) radiolabelling with compatible chelators affects the brain delivery and peripheral biodistribution of the bispecific antibody RmAb158-scFv8D3, which binds to amyloid-beta (Aβ) and the transferrin receptor (TfR), in Aβ pathology-expressing tg-ArcSwe mice and aged-matched wild-type control mice.
METHODS
Bispecific RmAb158-scFv8D3 (biAb) was radiolabelled with In using CHX-A"-DTPA, DOTA, or DOTA-tetrazine (DOTA-Tz). Affinity toward TfR and Aβ, as well as stability, was investigated . Mice were then intravenously administered with the three different radiolabelled biAb variants, and blood samples were collected for monitoring pharmacokinetics. Brain concentration was quantified after 2 and 72 h, and organ-specific retention was measured at 72 h by gamma counting. A subset of mice also underwent whole-body Single-photon emission computed tomography (SPECT) scanning at 72 h after injection. Following post-mortem isolation, the brains of tg-ArcSwe and WT mice were sectioned, and the spatial distribution of biAb was further investigated with autoradiography.
RESULTS
All three [In]biAb variants displayed similar blood pharmacokinetics and brain uptake at 2 h after administration. Radiolabelling did not compromise affinity, and all variants showed good stability, especially the DOTA-Tz variant. Whole-body SPECT scanning indicated high liver, spleen, and bone accumulation of all [In]biAb variants. Subsequent measurement of organ retention confirmed SPECT data, with retention in the spleen, liver, and bone - with very high bone marrow retention. gamma measurement of brain tissue, isolated at 72 h post-injection, and autoradiography showed that WT mice, despite the absence of Aβ, exhibited comparable brain concentrations of [In]biAb as those found in the tg-ArcSwe brain.
CONCLUSIONS
The successful In-labelling of biAb with retained binding to TfR and Aβ, and retained ability to enter the brain, demonstrated that In can be used to generate radioligands for brain imaging. A high degree of [In]biAb in bone marrow and intracellular accumulation in brain tissue indicated some off-target interactions or potential interaction with intrabrain TfR resulting in a relatively high non-specific background signal.
Topics: Animals; Indium Radioisotopes; Tomography, Emission-Computed, Single-Photon; Mice; Brain; Tissue Distribution; Amyloid beta-Peptides; Mice, Transgenic; Antibodies, Bispecific; Blood-Brain Barrier; Receptors, Transferrin; Radiopharmaceuticals; Alzheimer Disease
PubMed: 38863725
DOI: 10.48101/ujms.v129.10585 -
The Journal of Urology Jun 2024This study aimed to investigate the prevalence of pathogenic germline variants (PGVs) in hereditary cancer genes utilizing a universal testing approach and to determine...
PURPOSE
This study aimed to investigate the prevalence of pathogenic germline variants (PGVs) in hereditary cancer genes utilizing a universal testing approach and to determine the rate of PGVs that would have been missed based on National Comprehensive Cancer Network (NCCN) guidelines in genitourinary (GU) malignancies.
MATERIALS AND METHODS
A multisite, single-institution prospective germline genetic test (GGT) was universally offered to patients with new or active diagnoses of GU malignancies (prostate, bladder, and renal) from April 2018 to March 2020 at Mayo Clinic sites. Participants were offered GGT using a next-generation sequencing panel of > 80 genes. Demographic, tumor characteristics, and genetic results were evaluated. NCCN GU cancer guidelines were used to identify whether patients had incremental findings, defined as PGV-positive patients who would not have received testing based on NCCN guidelines.
RESULTS
Of 3095 individuals enrolled in the study, 601 patients had GU cancer (prostate = 358, bladder = 106, and renal = 137). The mean enrollment age was 67 years (SD 9.1), 89% were male, and 86% of patients were non-Hispanic White. PGVs were identified in 82 (14%) of all GU patients. PGV prevalence breakdown by cancer type was: 14% prostate, 14% bladder, and 13% renal cancer. Nearly one-third of identified PGVs were high penetrance, and the majority of these (67%) were clinically actionable. Incremental PGVs were identified in 28 (57%) prostate, 15 (100%) bladder, and 14 (78%) renal cancer patients. Of the 82 patients with PGV findings, 29 (35%) had at least 1 relative undergo cascade testing for the familial variant(s) identified.
CONCLUSIONS
More than 1 in 8 patients with GU malignancies were found to carry a PGV, with 67% of patients with high-penetrance PGVs undergoing clinically actionable changes. The majority of these PGVs would not have been identified based on current testing criteria. These findings support universal GGT for GU malignancies and underscore its potential to enhance risk assessment and guide precision interventions in urologic oncology.
PubMed: 38860938
DOI: 10.1097/JU.0000000000004089 -
The Journal of Pharmacology and... Jun 2024Radiation therapy, a standard treatment option for many cancer patients, induces DNA double strand breaks (DSBs), leading to cell death. Ataxia telangiectasia mutated...
Radiation therapy, a standard treatment option for many cancer patients, induces DNA double strand breaks (DSBs), leading to cell death. Ataxia telangiectasia mutated (ATM) kinase is a key regulator of DSB repair, and ATM inhibitors are being explored as radiosensitizers for various tumors, including primary and metastatic brain tumors. Efficacy of radiosensitizers for brain tumors may be influenced by a lack of effective drug delivery across the blood-brain barrier (BBB). The objective of this study was to evaluate the systemic pharmacokinetics and mechanisms that influence the CNS distribution of WSD0628, a novel and potent ATM inhibitor, in the mouse. Further, we have used these observations to form the basis of predicting effective exposures for clinical application. We observed a greater than dose proportional increase in exposure, likely due to saturation of clearance processes. Our results show that WSD0628 is orally bioavailable and CNS penetrant, with unbound partitioning in CNS (i.e., Kp) between 0.15 and 0.3. CNS distribution is not limited by the efflux transporters P-gp and Bcrp. WSD0628 is distributed uniformly amongst different brain regions. Thus, WSD0628 has favorable pharmacokinetic properties and potential for further exploration to determine the PK-PD-efficacy relationship in CNS tumors. This approach will provide critical insights for the clinical translation of WSD0628 for the treatment of primary and secondary brain tumors. This study evaluates the preclinical systemic pharmacokinetics, dose proportionality, and mechanisms influencing CNS distribution of WSD0628, a novel ATM inhibitor for the treatment of brain tumors. Results indicate that WSD0628 is orally bioavailable and CNS penetrant without efflux transporter liability. We also observed a greater than dose-proportional increase in exposure in both the plasma and brain. These favorable pharmacokinetic properties indicate WSD0628 has potential for further exploration for use as a radiosensitizer in the treatment of brain tumors.
PubMed: 38858089
DOI: 10.1124/jpet.123.001971 -
Translational Andrology and Urology May 2024Penile prosthesis implantation is an effective treatment for erectile dysfunction (ED) with high patient satisfaction and effectiveness. Unfortunately, infections remain... (Review)
Review
Penile prosthesis implantation is an effective treatment for erectile dysfunction (ED) with high patient satisfaction and effectiveness. Unfortunately, infections remain a dreaded complication, often necessitating device removal and imposing a substantial healthcare cost. Biofilms are communities of microorganisms encased in a self-produced polymeric matrix that can attach to penile prostheses. Biofilms have been demonstrated on the majority of explanted prostheses for both infectious and non-infectious revisions and are prevalent even in asymptomatic patients. Biofilms play a role in microbial persistence and exhibit unique antibiotic resistance strategies that can lead to increased infection rates in revision surgery. Biofilms demonstrate physical barriers through the development of an extracellular polymeric substance (EPS) that hinders antibiotic penetrance and the bacteria within biofilms demonstrate reduced metabolic activity that weakens the efficacy of traditional antibiotics. Despite these challenges, new methods are being developed and investigated to prevent and treat biofilms. These treatments include surface modifications, biosurfactants, tissue plasminogen activator (tPA), and nitric oxide (NO) to prevent bacterial adhesion and biofilm formation. Additionally, novel antibiotic treatments are currently under investigation and include antimicrobial peptides (AMPs), bacteriophages, and refillable antibiotic coatings. This article reviews biofilm formation, the challenges that biofilms present to conventional antibiotics, current treatments, and experimental approaches for biofilm prevention and treatment.
PubMed: 38855589
DOI: 10.21037/tau-23-550 -
Cureus May 2024Researching Waardenburg syndrome (WS) underscores its rarity and complex symptomatology, presenting as a congenital disorder predominantly inherited in an autosomal...
Researching Waardenburg syndrome (WS) underscores its rarity and complex symptomatology, presenting as a congenital disorder predominantly inherited in an autosomal dominant pattern. It exhibits incomplete penetrance, which results in a wide range of clinical manifestations, with variable phenotypic presentations within the same family as well. The most commonly found features are facial abnormalities, hypopigmentation of the skin, heterochromia iridis, and conductive deafness. Adding to the eccentricities of this syndrome are its four subtypes, each presenting with its specific clinical features, which helps in delineating the subtype. A mutated paired box 3 () gene manifests as type 1 Waardenburg, which is characterized by sideways displacement of the inner angles of the eyes (i.e., dystopia canthorum), widely spaced eyes, congenital sensorineural hearing impairment, and patchy pigmentation of the iris, skin, and hair. Due to insufficient research, it has been difficult to isolate all the genetic mutations responsible for type 2, but its phenotype is very similar to type 1 with minor differences. Type 3 is characterized by musculoskeletal abnormalities. Waardenburg-Shah syndrome (type 4), which is associated with Hirschsprung disease, is the rarest subtype and is caused by genetic mutations in the endothelin receptor type B (), endothelin-3 (), or sex-determining region Y (SRY) box 10 () gene. We present a case series of this unique subtype that presented with a typical history of constipation due to Hirschsprung disease and had phenotypic manifestations of white forelock, heterochromia iridis, and bilateral sensorineural hearing loss (SNHL). In parallel with a positive 1° family history of a white forelock, we reflect on the fundamentals of this unique syndrome, as well as its management protocols, highlighting the importance of genetic counseling and cultivation of a high index of suspicion for its diagnosis.
PubMed: 38854277
DOI: 10.7759/cureus.59858 -
JCO Global Oncology Jun 2024In high-income countries, 2%-10% of tumor genomic profiling (TGP) reports reveal incidental pathogenic germline variants. A third of these patients would not qualify for...
PURPOSE
In high-income countries, 2%-10% of tumor genomic profiling (TGP) reports reveal incidental pathogenic germline variants. A third of these patients would not qualify for genetic testing on the basis of current guidelines. Our study determined the prevalence of potentially pathogenic germline variants (PPGVs) in TGP results of adult patients with solid malignancies in the Philippines.
METHODS
Annotated reports of patients with solid cancers who underwent TGP using FoundationOne or FoundationOne Heme between January 2021 and July 2023 were reviewed. PPGV criteria include having a variant allele frequency of >30% and were categorized as (1) high penetrance gene (HP), founder variant (FV), or variant associated with clinical presentation (VA). Pathogenicity was crosschecked through the ClinVar database.
RESULTS
Of 446 patients, 13 PPGV variants were found in 50 (11.2%) patients at a median age of 60.5 years. Of them, 28 (56%) had HP (, , , , , , ), 25 (50%) patients had VA (, , , , ), and two patients with lung cancer had a FV ( p.Thr790Met). Six patients had more than one PPGV. PPGVs were primarily found in patients with colorectal (42% of 50 patients with PPGVs), breast (16%), ovarian (6%), and lung (6%) cancer ( < .001). HP genes were mostly found in female patients (71.4%; = .03).
CONCLUSION
With a PPGV prevalence of 11% in this study, it is important to recognize PPGVs as it can prompt genetic counseling and confirmatory germline testing.
Topics: Humans; Female; Male; Philippines; Middle Aged; Germ-Line Mutation; Neoplasms; Aged; Adult; Prevalence; Genetic Predisposition to Disease; Genetic Testing; Aged, 80 and over; Genomics
PubMed: 38843470
DOI: 10.1200/GO.24.00019 -
European Journal of Human Genetics :... Jun 2024Protection of Telomeres Protein 1 (POT1) protein is an essential subunit of the shelterin telomere binding complex, regulating telomere length. Some POT1 gene pathogenic...
Protection of Telomeres Protein 1 (POT1) protein is an essential subunit of the shelterin telomere binding complex, regulating telomere length. Some POT1 gene pathogenic variants (PV) lead to telomere elongation, genomic instability and higher risk of cancer. POT1 tumour predisposition syndrome (POT1-TPD) has autosomal dominant inheritance and unknown penetrance. It is associated with increased risk of cutaneous melanoma, chronic lymphocytic leukaemia, angiosarcoma and gliomas. In this work, we aim to describe a broader cancer phenotype related to POT1-TPD, in three families (two with a four generation pedigree, one with a five generation pedigree). The three index cases were referred to our oncogenetic centre for genetic counselling due to their personal history of cancer. Two underwent clinical exome sequencing of 4,867 genes associated with Mendelian genetic diseases, and another underwent gene panel sequencing including POT1, which identified three different POT1 PV: NC_000007.14(NM_015450.2):c.349C>T; NC_000007.14(NM_015450.2):c.233T>C and NC_000007.14(NM_015450.2):c.818G>A; already described in the literature. Referenced relatives, did a target genetic test (according to the POT1 PV identified in the family). In total, 37 individuals were tested (51.4% females), median age of 46 (22-81) years, with POT1 PV detected in 22. POT1-TPD was observed, but also a higher incidence of other cancers (other sarcomas, papillary thyroid cancer, early onset prostate cancer and leukaemia). These findings contribute to an increase in our knowledge about POT1 PV, and it can play a role in the definition of future POT1 PV screening criteria, POT1 carrier surveillance protocols (possibly considering screening for all types of sarcomas) and in genetic counselling.
PubMed: 38839987
DOI: 10.1038/s41431-024-01611-0 -
Science Translational Medicine Jun 2024Progranulin (PGRN) haploinsufficiency is a major risk factor for frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43) pathology (FTLD-). Multiple...
Progranulin (PGRN) haploinsufficiency is a major risk factor for frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43) pathology (FTLD-). Multiple therapeutic strategies are in clinical development to restore PGRN in the CNS, including gene therapy. However, a limitation of current gene therapy approaches aimed to alleviate FTLD-associated pathologies may be their inefficient brain exposure and biodistribution. We therefore developed an adeno-associated virus (AAV) targeting the liver (L) to achieve sustained peripheral expression of a transferrin receptor (TfR) binding, brain-penetrant (b) PGRN variant [AAV(L):bPGRN] in two mouse models of FTLD-, namely, knockout and double knockout mice. This therapeutic strategy avoids potential safety and biodistribution issues of CNS-administered AAVs and maintains sustained concentrations of PGRN in the brain after a single dose. AAV(L):bPGRN treatment reduced several FTLD--associated pathologies including severe motor function deficits, aberrant TDP-43 phosphorylation, dysfunctional protein degradation, lipid metabolism, gliosis, and neurodegeneration in the brain. The potential translatability of our findings was tested in an in vitro model using cocultured human induced pluripotent stem cell (hiPSC)-derived microglia lacking PGRN and TMEM106B and wild-type hiPSC-derived neurons. As in mice, aberrant TDP-43, lysosomal dysfunction, and neuronal loss were ameliorated after treatment with exogenous TfR-binding protein transport vehicle fused to PGRN (PTV:PGRN). Together, our studies suggest that peripherally administered brain-penetrant PGRN replacement strategies ameliorate FTLD- relevant phenotypes including TDP-43 pathology, neurodegeneration, and behavioral deficits. Our data provide preclinical proof of concept for the use of this AAV platform for treatment of FTLD- and potentially other CNS disorders.
Topics: Animals; Humans; Mice; Brain; Dependovirus; Disease Models, Animal; DNA-Binding Proteins; Frontotemporal Lobar Degeneration; Genetic Therapy; Mice, Knockout; Phosphorylation; Progranulins; Receptors, Transferrin
PubMed: 38838131
DOI: 10.1126/scitranslmed.adj7308 -
Proceedings of the National Academy of... Jun 2024Alcohol dehydrogenase 1B (ADH1B) is a primate-specific enzyme which, uniquely among the ADH class 1 family, is highly expressed both in adipose tissue and liver. Its...
Alcohol dehydrogenase 1B (ADH1B) is a primate-specific enzyme which, uniquely among the ADH class 1 family, is highly expressed both in adipose tissue and liver. Its expression in adipose tissue is reduced in obesity and increased by insulin stimulation. Interference with expression has also been reported to impair adipocyte function. To better understand the role of ADH1B in adipocytes, we used CRISPR/Cas9 to delete in human adipose stem cells (ASC). Cells lacking ADH1B failed to differentiate into mature adipocytes manifested by minimal triglyceride accumulation and a marked reduction in expression of established adipocyte markers. As ADH1B is capable of converting retinol to retinoic acid (RA), we conducted rescue experiments. Incubation of ADH1B-deficient preadipocytes with 9-cis-RA, but not with all-transretinol, significantly rescued their ability to accumulate lipids and express markers of adipocyte differentiation. A homozygous missense variant in (p.Arg313Cys) was found in a patient with congenital lipodystrophy of unknown cause. This variant significantly impaired the protein's dimerization, enzymatic activity, and its ability to rescue differentiation in ADH1B-deficient ASC. The allele frequency of this variant in the Middle Eastern population suggests that it is unlikely to be a fully penetrant cause of severe lipodystrophy. In conclusion, ADH1B appears to play an unexpected, crucial and cell-autonomous role in human adipocyte differentiation by serving as a necessary source of endogenous retinoic acid.
Topics: Humans; Alcohol Dehydrogenase; Adipogenesis; Adipocytes; Tretinoin; Cell Differentiation; CRISPR-Cas Systems; Mutation, Missense; Adipose Tissue
PubMed: 38838011
DOI: 10.1073/pnas.2319301121 -
Frontiers in Genetics 2024Variants in the gene are a frequent cause of hypertrophic cardiomyopathy (HCM) but display a large phenotypic heterogeneity. Founder mutations are often believed to be...
BACKGROUND
Variants in the gene are a frequent cause of hypertrophic cardiomyopathy (HCM) but display a large phenotypic heterogeneity. Founder mutations are often believed to be more benign as they prevailed despite potential negative selection pressure. We detected a pathogenic variant in (del exon 23-26) in several probands. We aimed to assess the presence of a common haplotype and to describe the cardiac characteristics, disease severity and long-term outcome of mutation carriers.
METHODS
Probands with HCM caused by a pathogenic deletion of exon 23-26 of were identified through genetic screening using a gene panel encompassing 59 genes associated with cardiomyopathies in a single genetic center in Belgium. Cascade screening of first-degree relatives was performed, and genotype positive relatives were further phenotyped. Clinical characteristics were collected from probands and relatives. Cardiac outcomes included death, heart transplantation, life-threatening arrhythmia, heart failure hospitalization or septal reduction therapy. Haplotype analysis, using microsatellite markers surrounding , was performed in all index patients to identify a common haplotype. The age of the founder variant was estimated based on the size of the shared haplotype using a linkage-disequilibrium based approach.
RESULTS
We identified 24 probands with HCM harbouring the exon 23-26 deletion. Probands were on average 51 ± 16 years old at time of clinical HCM diagnosis and 62 ± 10 years old at time of genetic diagnosis. A common haplotype of 1.19 Mb was identified in all 24 probands, with 19 of the probands sharing a 13.8 Mb haplotype. The founder event was estimated to have happened five generations, or 175-200 years ago, around the year 1830 in central Flanders. Through cascade screening, 59 first-degree relatives were genetically tested, of whom 37 (62.7%) were genotype positive (G+) and 22 (37.3%) genotype negative (G-). They were on average 38 ± 19 years old at time of genetic testing. Subsequent clinical assessment revealed a HCM phenotype in 19 (51.4%) G+ relatives. Probands were older (63 ± 10 vs. 42 ± 21 years; < 0.001) and had more severe phenotypes than G+ family members, presenting with more symptoms (50% vs. 13.5%; = 0.002), arrhythmia (41.7% vs. 12.9%, = 0.014), more overt hypertrophy and left ventricular outflow tract obstruction (43.5% vs. 3.0%; < 0.001). Male G+ relatives more often had a HCM phenotype (78.6% vs. 34.8%; = 0.010) and were more severely affected than females. At the age of 50, a penetrance of 78.6% was observed, defined as the presence of HCM in 11 of 14 G+ relatives with age ≥50 years. Overall, 20.3% of all variant carriers developed one of the predefined cardiac outcomes after a median follow-up of 5.5 years with an average age of 50 (±21) years.
CONCLUSION
A Belgian founder variant, an exon 23-26 deletion in , was identified in 24 probands and 37 family members. The variant is characterized by a high penetrance of 78.6% at the age of 50 years but has variable phenotypic expression. Adverse outcomes were observed in 20.3% of patients during follow-up.
PubMed: 38836037
DOI: 10.3389/fgene.2024.1392527