Can tandem alternative splicing and evasion of premature termination codon surveillance contribute to attenuated Peutz-Jeghers syndrome?

Alternative use of short distance tandem sites such as NAGNn AG are a common mechanism of alternative splicing; however, single nucleotide variants are rarely reported as likely to generate or to disrupt tandem splice sites. We identify a pathogenic intron 5 STK11 variant (NM_000455.4:c.[735-6A>G];[=]) segregating with the mucocutaneous features but not the hamartomatous polyps of Peutz-Jeghers syndrome in two individuals. By RNAseq analysis of peripheral blood mRNA, this variant was shown to generate a novel and preferentially used tandem proximal splice acceptor (AAGTGAAG). The variant transcript (NM_000455.4:c.734_734 + 1insTGAAG), which encodes a frameshift (p.[Tyr246Glufs*43]) constituted 36%-43% of STK11 transcripts suggesting partial escape from nonsense mediated mRNA decay and translation of a truncated protein. A review of the ClinVar database identified other similar variants. We suggest that nucleotide changes creating or disrupting tandem alternative splice sites are a pertinent disease mechanism and require contextualization for clinical reporting. Additionally, we hypothesize that some pathogenic STK11 variants cause an attenuated phenotype.

Comprehensive Genome Analysis of Neisseria meningitidis from South America Reveals a Distinctive Pathogenicity-Related Prophage Repertoire.

Neisseria meningitidis, a bacterium that colonizes in the human nasopharynx, occasionally causes invasive meningococcal disease leading to meningitis or septicemia. Different serogroups and lineages (clonal complexes) are related to the occurrence and epidemiology of N. meningitidis. Despite vaccines for most serogroups, N. meningitidis lineages causing unusual clinical manifestations and a higher fatality rate compared to other lineages have been reported in South America. The present study focused on exploring the diversity of N. meningitidis prophages from South America and their relationship with the epidemiological variables of these strains. We found a high diversity of prophages among the different clonal complexes. By comparing them with previously described N. meningitidis phages and prophages, we revealed groups of prophages sharing similar compositions, which could be useful for prophage comparison in N. meningitidis. Furthermore, we observed a high correlation between the prophage content and epidemiological features, e.g., pathogenicity or clonal complex. Additionally, a distinctive filamentous prophage named here as IMSAR-11 (Invasive Meningococci from South America Related to cc11) was identified. Interestingly, two versions of IMSAR-11, circular and chromosomally integrated, were found. Overall, this study reinforces the importance of the genomic characterization of circulating N. meningitidis lineages to generate new targets for lineage monitoring, diagnosis, or appropriateness of vaccine development. Further studies are necessary to understand the role of these prophages in the persistence, dispersal, and virulence of N. meningitidis in the world.

Implications of Splicing Alterations in the Onset and Phenotypic Variability of a Family with Subclinical Manifestation of Peutz-Jeghers Syndrome: Bioinformatic and Molecular Evidence.

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant pre-cancerous disorder caused in 80-90% of cases by germline mutations in the tumor suppressor gene STK11. We performed a genetic test of the STK11 gene in two Italian young sisters suspected of PJS, since they showed pathognomonic café au lait spots in absence of other symptoms and familiarity. Sequencing of all exons of STK11 gene and other 8 genes, suggested to be involved in hamartomatous syndromes, (PTEN, BMPR1A, SDHB, SDHD, SMAD4, AKT1, ENG, PIK3CA) led to the identification in both the probands of a novel germline silent mutation named c.597 G>A, hitting the last nucleotide of exon 4. Interestingly, genetic testing of the two probands' parents showed that their unaffected father was carrier of this mutation. Moreover, he carried a second intronic substitution named c.465-51 T>C (rs2075606) which was not inherited by his daughters. We also observed that all the family members carrying the c.597 G>A mutation presented an aberrant splice variant of STK11 mRNA lacking exon 4. Furthermore, in silico analysis of c.465-51 T>C substitution showed that it may activate an Enhancer Splicing Element. Finally, qRT-PCR analysis of STK11 expression levels showed a slight downregulation of the wild type allele in the father and a 2-fold downregulation in the probands compared to the unaffected mother. Our results have led the hypothesis that the c.465-51 T>C intronic variant, which segregates with the wild type allele, could increase the splicing effectiveness of STK11 wild-type allele and compensate the side effect of the c.597 G>A splicing mutation, being responsible for the phenotypic variability observed within this family. This finding highlight the importance of RNA analysis in genetic testing, remarking that silent DNA variant can often be splicing variant involved in disease onset and progression. The identification of these variants has a crucial role to ensure an appropriate follow-up and cancer prevention in at-risk individuals.

Hetiamacin E and F, New Amicoumacin Antibiotics from Bacillus subtilis PJS Using MS/MS-Based Molecular Networking.

To combat escalating levels of antibiotic resistance, novel strategies are developed to address the everlasting demand for new antibiotics. This study aimed at investigating amicoumacin antibiotics from the desert-derived Bacillus subtilis PJS by using the modern MS/MS-based molecular networking approach. Two new amicoumacins, namely hetiamacin E (1) and hetiamacin F (2), were finally isolated. The planar structures were determined by analysis of extensive NMR spectroscopic and HR-ESI-MS data, and the absolute configurations were concluded by analysis of the CD spectrum. Hetiamacin E (1) showed strong antibacterial activities against methicillin-sensitive and resistant Staphylococcus epidermidis at 2-4 µg/mL, and methicillin-sensitive and resistant Staphylococcus aureus at 8-16 µg/mL. Hetiamacin F (2) exhibited moderate antibacterial activities against Staphylococcus sp. at 32 µg/mL. Both compounds were inhibitors of protein biosynthesis demonstrated by a double fluorescent protein reporter system.

The altered activity of P53 signaling pathway by STK11 gene mutations and its cancer phenotype in Peutz-Jeghers syndrome.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is caused by mutations in serine/threonine kinase 11 (STK11) gene. The increased cancer risk has been connected to P53 pathway. METHODS: PJS probands with STK11 mutation were included in the function analysis. P53 activity elevated by STK11 mutants was investigated using dual-luciferase reporter assay in vitro after constructing expression vectors of STK11 wild type and mutants generated by site-directed substitution. The association between the P53 activity and clinicopathological factors was analysis, especially the cancer history. RESULTS: Thirteen probands with STK11 mutations were involved, and within the mutations, c.G924A was novel. P53 activity elevation caused by 6 truncating mutations were significantly lower than that of STK11 wild type (P < 0.05). Family history of cancer was observed in 5 families. Within them, P53 activity was reduced and cancer occurred before 40 in 2 families, while it was not significantly changed and cancers happened after 45 in the other 3 families. CONCLUSIONS: The affected P53 activity caused by STK11 mutations in PJS patients is significantly associated with protein truncation, while cancer risk in PJS can be elevated through pathways rather than P53 pathway. P53 activity test is probably a useful supporting method to predict cancer risk in PJS, which could be helpful in clinical practice.

Loss of the tumor suppressor LKB1 promotes metabolic reprogramming of cancer cells via HIF-1α.

One of the major metabolic changes associated with cellular transformation is enhanced nutrient utilization, which supports tumor progression by fueling both energy production and providing biosynthetic intermediates for growth. The liver kinase B1 (LKB1) is a serine/threonine kinase and tumor suppressor that couples bioenergetics to cell-growth control through regulation of mammalian target of rapamycin (mTOR) activity; however, the influence of LKB1 on tumor metabolism is not well defined. Here, we show that loss of LKB1 induces a progrowth metabolic program in proliferating cells. Cells lacking LKB1 display increased glucose and glutamine uptake and utilization, which support both cellular ATP levels and increased macromolecular biosynthesis. This LKB1-dependent reprogramming of cell metabolism is dependent on the hypoxia-inducible factor-1α (HIF-1α), which accumulates under normoxia in LKB1-deficient cells and is antagonized by inhibition of mTOR complex I signaling. Silencing HIF-1α reverses the metabolic advantages conferred by reduced LKB1 signaling and impairs the growth and survival of LKB1-deficient tumor cells under low-nutrient conditions. Together, our data implicate the tumor suppressor LKB1 as a central regulator of tumor metabolism and growth control through the regulation of HIF-1α-dependent metabolic reprogramming.

Three novel mutations of STK11 gene in Chinese patients with Peutz-Jeghers syndrome.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder characterized by gastrointestinal (GI) hamartomatous polyps, mucocutaneous hyperpigmentation, and an increased risk of cancer. Mutations in the serine-threonine kinase 11 gene (SKT11) are the major cause of PJS. CASE PRESENTATION: Blood samples were collected from six PJS families including eight patients. Mutation screening of STK11 gene was performed in these six families by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) assay. Three novel mutations (c.721G > C, c.645_726del82, and del(exon2-5)) and three recurrent mutations (c.752G > A, c.545 T > C and del(exon1)) in STK11 were detected in six Chinese PJS families. Genotype-phenotype correlations suggested that truncating mutations trend to result in severe complications. CONCLUSION: These findings broaden the mutation spectrum of the STK11 gene and would help clinicians and genetic counselors provide better clinical surveillance for PJS patients, especially for ones carrying truncating mutation.

Uncommon manifestation of Peutz-Jeghers syndrome: a case of jejuno-jejunal intussusception and volvulus leading to small bowel obstruction.

Peutz-Jeghers syndrome (PJS) is a rare genetic disorder causing gastrointestinal polyps and skin pigmentation. Our case report highlights a unique instance of jejuno-jejunal intussusception associated with PJS in a 28-year-old female patient who presented to the emergency department with colicky abdominal pain, tachycardia, and gastrointestinal symptoms. Physical examination revealed mucocutaneous hyperpigmentation. Imaging studies showed a U-shaped distension in the jejunum with thickening and pneumatosis. Laparotomy revealed a jejuno-jejunal volvulus with intussusception. Surgical resection successfully addressed gangrenous jejunal tissue and ileal polyps. Histopathology confirmed PJS polyps. Postoperatively, the patient recovered well and was discharged. Family history revealed similar skin lesions in her uncle. Our case highlights the need for prompt surgical intervention to address complications associated with PJS and elucidates a unique presentation of PJS involving jejuno-jejunal intussusception and volvulus leading to complete small bowel obstruction. We aim to deepen understanding and prompt discussions on optimal therapeutic strategies.

Collecting and Delivering Fattened Pigs to the Abattoir.

In the context of pig farming, this paper addresses the optimization problem of collecting fattened pigs from farms to deliver them to the abattoir. Assuming that the pig sector is organized as a competitive supply chain with narrow profit margins, our aim is to apply analytics to cope with the uncertainty in production costs and revenues. Motivated by a real-life case, the paper analyzes a rich Team Orienteering Problem (TOP) with a homogeneous fleet, stochastic demands, and maximum workload. After describing the problem and reviewing the related literature, we introduce the PJS heuristic. Our approach is first compared with exact methods, which are revealed as computationally unfeasible. Later, a scenario analysis based on a real instance was performed to gain insight into the practical aspects. Our findings demonstrate a positive correlation between the number of alternative routes explored, the number of trips, the transportation cost, and the maximum reward. Regarding the variability in the number of pigs to collect, when a truck can visit more than one farm, better solutions can be found with higher variability since the load can be combined more efficiently.

Immune profiling of premalignant lesions in patients with Peutz-Jeghers syndrome.

BACKGROUND: Peutz-Jeghers syndrome (PJS), is a rare autosomal dominant hereditary disease characterized by an elevated risk of various cancers. Serine/Threonine Kinase 11 (STK11) gene is a major tumor suppressor crucial for immune evasion with and beyond tumorigenic cells. It has garnered increasing attention in the realm of oncology treatment, particularly in the context of immunotherapy development. OBJECTIVE: This study aimed to assess the suitability of polyps obtained from individuals with PJS, resulting from germline STK11 deficiency, for immunotherapy. Additionally, we seek to identify potential shared mechanisms related to immune evasion between PJS polyps and cancers. To achieve this, we examined PJS polyps alongside familial adenomatous polyposis (FAP) and sporadic polyps. METHODS: Polyps were compared among themselves and with either the paracancerous tissues or colon cancers. Pathological and gene expression profiling approaches were employed to characterize infiltrating immune cells and assess the expression of immune checkpoint genes. RESULTS: Our findings revealed that PJS polyps exhibited a closer resemblance to cancer tissues than other polyps in terms of their immune microenvironment. Notably, PJS polyps displayed heightened expression of the immune checkpoint gene CD80 and an accumulation of myeloid cells, particularly myeloid-derived suppressor cells (MDSCs). CONCLUSION: The findings suggest an immunobiological foundation for the increased cancer susceptibility in PJS patients, paving the way for potential immune therapy applications in this population. Furthermore, utilizing PJS as a model may facilitate the exploration of immune evasion mechanisms, benefiting both PJS and cancer patients.

A novel stop codon mutation in STK11 gene is associated with Peutz-Jeghers Syndrome and elevated cancer risk: a case study.

Based on the analysis of patients with Peutz-Jeghers syndrome (PJS), Serine threonine kinase11 (STK11) is known as a tumor suppressor gene, which is involved in cell polarization, regulation of apoptosis, and DNA damage response. In this case report study, we examined STK11 gene sequencing in a 42-year-old woman with mucocuta neous pigmentation and positive family history. Endoscopy and colonoscopy showed >1000 polyps throughout the stomach/colon (PJ-type hamartomas). The larger polyp in the stomach was resected and the small bowel imaging detected multiple jejunum/ileum small polyps. The data released from the sequencing results revealed five alterations in exons 1 to 5. The major mutation in stop codon was reported as converted to the amino acid tryptophan (TRP) to tyrosine (TER). The TGG codon was converted to TAG by mutation. Finally, another novel mutation in STK11 stop codon as a 'de novo' variant was seen. It is predicted that stop codon mutations make the affected person susceptible to developing colorectal cancer.

A Case of Solitary Peutz-Jeghers Syndrome Leading to Chronic Small Bowel Obstruction Due to Intussusception From a Large Hamartomatous Polyp.

We report a case of a 33-year-old male who presented to the emergency department with a three-day history of severe diffuse abdominal pain associated with anorexia, nausea, and vomiting. Computed tomography (CT) imaging of the abdomen and pelvis revealed a long segment of intussusception in the proximal jejunum and a round lesion along the intussusception with punctate hyperdensities. The patient underwent a diagnostic laparoscopy converted to open small bowel resection and end-to-end anastomosis that demonstrated a pedunculated jejunal mass. The mass was removed, and the pathology revealed a hamartomatous polyp with features of Peutz-Jeghers syndrome (PJS). The patient did not have a family history, previous endoscopic findings, or physical exam findings such as mucocutaneous pigmentation that could be attributed to PJS.  Definitive diagnosis of solitary PJS-type hamartomatous polyps depends on histopathological findings. Genetic analysis for mutations of the PJS susceptible gene, STK11/LB1 located at 19p13.3, as well as loss of heterozygosity at that locus, have been used for the diagnosis of PJS. In patients with large pedunculated hamartomatous polyps, chronic intussusception can occur. If pathology reveals features of Peutz-Jeghers, but the patient lacks the characteristic mucocutaneous pigmentation, family history of PJS, or additional polyps within the GI tract, then solitary PJS may be suspected.

Potential factors affecting success rate and long term outcome in single balloon enteroscopy-assisted therapeutic endoscopic retrograde cholangiopancreatography in patients with pancreaticojejunal anastomotic stenosis: a retrospective study.

Background: Pancreaticojejunal anastomotic stenosis (PJS) after pancreaticoduodenectomy (PD) is difficult to treat. Single-balloon enteroscope-assisted endoscopic retrograde pancreatography (SBE-assisted ERP) is a safe way to treat PJS with the strength of minimally invasion and repeatability, but since its technical difficulty and few patient number, data on long-term outcomes remain limited. The optimal treatment is still unknown. We aim to study the safety, effectiveness, and long-term outcome of single balloon enteroscopy-assisted (SBE-assisted) therapeutic ERP in patients with PJS in this study. Methods: The clinical information of patients undergoing SBE-assisted therapeutic ERP from March 2016 to March 2021 were retrospectively analyzed. All patients were diagnosed as PJS and without any contraindication for therapeutic endoscopy. Treatment details, postoperative complications, factors influencing technical success rate were evaluated. Long-term outcomes results were obtained by clinical or telephone follow-up. Results: Sixteen patients with median age of 51 years were included in this study, surgical reconstruction methods including PD with Whipple reconstruction, PD with Child reconstruction, pylorus-preserving pancreaticoduodenectomy (PpPD) with Whipple reconstruction. Eight patients were successfully treated. No serious complications happened. Risk factors for the failure of pancreaticojejunal anastomotic site identification include the digestive tract reconstruction sequence, pancreaticojejunostomy method, pancreatic duct tube implantation, pancreatic duct width before surgery, and pancreatic fistula during perioperative period. The median follow-up time was 77.2 months, the mean indwelling time of the stent was 62.3 months [interquartile range (IQR), 6.8-153.7 months]. Two of eight patients developed recurrent PJS. The variation in body mass index (BMI) was +2.46 in the non-recurrence group compared to -1.09 in the recurrence group and -2.12 in the endoscopic retrograde cholangiopancreatography (ERCP) treatment failure group. Conclusions: ERP intervention should be carried out early once PJS occurs in order to increase success rate. BMI is a crucial indicator which can reflex PJS rehabilitation degree during follow-up. In order to reduce PJS recurrence rate, a wider pancreatic stent and a longer stent indwelling time are recommended.

Gastroduodenal Intussusception in Peutz-Jeghers Syndrome.

Teaching points: Gastroduodenal intussusception is an infrequent cause of abdominal pain in children, for which a lead-point is nearly ubiquitous, which imposes endoscopic reduction as the first line of treatment.

Strong Hereditary Predispositions to Colorectal Cancer.

Cancer is one of the most common causes of death worldwide. A strong predisposition to cancer is generally only observed in colorectal cancer (5% of cases) and breast cancer (2% of cases). Colorectal cancer is the most common cancer with a strong genetic predisposition, but it includes dozens of various syndromes. This group includes familial adenomatous polyposis, attenuated familial adenomatous polyposis, MUTYH-associated polyposis, NTHL1-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, Lynch syndrome, and Muir-Torre syndrome. The common symptom of all these diseases is a very high risk of colorectal cancer, but depending on the condition, their course is different in terms of age and range of cancer occurrence. The rate of cancer development is determined by its conditioning genes, too. Hereditary predispositions to cancer of the intestine are a group of symptoms of heterogeneous diseases, and their proper diagnosis is crucial for the appropriate management of patients and their successful treatment. Mutations of specific genes cause strong colorectal cancer predispositions. Identifying mutations of predisposing genes will support proper diagnosis and application of appropriate screening programs to avoid malignant neoplasm.

Multidisciplinary management for Peutz-Jeghers syndrome and prevention of vertical transmission to offspring using preimplantation genetic testing.

BACKGROUND: Peutz Jeghers syndrome (PJS) is an autosomal dominant genetic disorder caused by STK11 mutation with a predisposition to gastrointestinal polyposis and cancer. PJS patients suffer poor quality of life and are highly concerned about whether deleterious mutations transmit to their offspring. Therefore, this study aimed to propose feasible clinical management and provide effective preimplantation genetic testing for monogenic defect (PGT-M) strategies to protect offspring from inheriting the disease. METHODS: A hospital-based clinical retrospective analysis reviewing the clinical characteristics and fertility aspects was first conducted on 51 PJS patients at the First Affiliated Hospital of Zhengzhou University between January 2016 and March 2021. Among the 51 patients, the PGT-M strategy was further carried out in 4 couples, which started with a biopsy of the trophectoderm cells of embryos and whole genome amplification using multiple displacement amplification. Thereafter, single nucleotide polymorphism linkage analyses based on karyomapping were performed with copy number variations of the embryos identified simultaneously. Finally, prenatal diagnosis was used to verify the validity of the PGT-M results. RESULTS: A comprehensive management flowchart adopted by the multidisciplinary team model was formulated mainly focusing on clinical genetic and gastrointestinal aspects. Under the guidelines of this management, 32 embryos from 4 PJS pedigrees were diagnosed and 2 couples successfully conceived healthy babies free of the STK11 pathogenic mutation. CONCLUSIONS: Our comprehensive management could help affected families avoid having children with PJS through preimplantation genetic testing and provide meaningful guidance for multidisciplinary clinical practice on PJS.

Peutz-Jeghers Syndrome and the Role of Imaging: Pathophysiology, Diagnosis, and Associated Cancers.

The Peutz-Jeghers Syndrome (PJS) is an autosomal dominant neoplastic syndrome defined by hamartomatous polyps through the gastrointestinal tract, development of characteristic mucocutaneous pigmentations, and an elevated lifetime cancer risk. The majority of cases are due to a mutation in the STK11 gene located at 19p13.3. The estimated incidence of PJS ranges from 1:50,000 to 1:200,000. PJS carries an elevated risk of malignancies including gastrointestinal, breast, lung, and genitourinary (GU) neoplasms. Patients with PJS are at a 15- to 18-fold increased malignancy risk relative to the general population. Radiologists have an integral role in the diagnosis of these patients. Various imaging modalities are used to screen for malignancies and complications associated with PJS. Awareness of various PJS imaging patterns, associated malignancies, and their complications is crucial for accurate imaging interpretation and patient management. In this manuscript, we provide a comprehensive overview of PJS, associated malignancies, and surveillance protocols.

Analysis of a pedigree of Peutz-Jeghers syndrome and RET proto-oncogene mutation: one case report and literature review.

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder characterised by gastrointestinal (GI) hamartomatous polyposis and mucocutaneous pigmentations. PJS is associated with an increased cancer risk, including GI and various extra-GI malignancies. In this study, we tracked this family for 8 years, and analyzed the clinical data of the PJS pedigree including two generations. In our research, the studied family members, including the proband, older daughter and younger daughter, all detected to have three heterozygous mutations in the RET gene that were inherited from the proband. The existed three mutant spots included exon 5 (GTG>ATG, Val292Met), exon 2 (CGC>CAC, Arg67His) and exon 18 (CGC>TGC, Arg982Cys) in RET. Our study provides an observation of the genetic heterogeneity of PJS. This pedigree investigation showed that it is critical to establish a long-term follow-up system for PJS patients and their families.

Micronucleus Frequency in Exfoliated Buccal Cells of Children Living in an Industrialized Area of Apulia (Italy).

Micronuclei (MN) are biomarkers of early biological effect often used for detecting DNA damage in human population exposed to genotoxic agents. The aim of this study was to evaluate the frequency of MN in exfoliated buccal cells of children living in an industrialized (impacted) area compared with that found in children living in a control area without significant anthropogenic impacts. A total of 462 6-8-year-old children (206 in the impacted area, 256 in the control area) attending primary school were enrolled. A questionnaire was administered to the parents of the recruited children to obtain information about personal data, lifestyles, and food habits of their children. Atmospheric particulate fractions were collected near the involved schools to assess the level of environmental exposure of the children. The presence of MN was highlighted in 68.4% of children living in the impacted area with a mean MN frequency of 0.66‱ ± 0.61‱. MN positivity and frequency were significantly lower in the control area (37.1% and 0.27‱ ± 0.43‱, respectively). The frequency of MN was positively associated with quasi-ultrafine particulate matter (PM0.5), traffic near the home, and consuming barbecued food; while adherence to the Mediterranean diet and practicing sport were negatively associated.

Low-level parental mosaicism in an apparent de novo case of Peutz-Jeghers syndrome.

We report the case of a female found to have mosaicism for mutation in the STK11 gene, with the mutant allele expressed in her gametes, evident by her affected offspring, and in her gastrointestinal tract demonstrated on an excised polyp analysed for diagnosis. Mosaicism for Peutz-Jeghers syndrome (PJS) has been reported in a small number of cases previously but a clinical presentation such as this has not previously been described. This finding of mosaicism was several years after initial investigations failed to identify the same STK11 mutation in this woman whose son was diagnosed with PJS at a young age. This case highlights the importance of considering mosaicism as an explanation for apparent de novo cases of PJS syndrome. It also has implications for genetic counselling, predictive testing and cancer screening.