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The article discusses a case report of a 53-year-old woman with Birt-Hogg-Dubé syndrome (BHD) who developed metastatic chromophobe renal cell carcinoma (RCC) after the removal of a primary tumor smaller than 3 cm. The patient underwent partial nephrectomy followed by radical nephrectomy, and later developed omental metastases. Genetic testing confirmed the diagnosis of BHD, and the patient was treated with immunotherapy. The article raises questions about the effectiveness of the 3 cm rule in BHD patients and calls for further research in large BHD case series to reconsider screening recommendations. [Extracted from the article]

Background: Birt-Hogg-Dubé (BHD) syndrome is a genetic condition caused by pathogenic variants in the FLCN gene resulting in benign skin lesions, spontaneous pneumothorax, and increased risk for a variety of renal tumors. Skin manifestations of BHD include trichodiscoma (TD) and fibrofolliculoma (FF), which may represent the same pathologic entity. These lesions can identify BHD patients, who upon positive genetic testing can be considered for life-long surveillance for renal neoplasms. Objective: To characterize patients diagnosed with TD and FF including rates and outcomes of genetics referral. Methods: Retrospective chart reviews of patients with confirmed or possible diagnosis of TD or FF at the University of Michigan from September 2002 through October 2020 to assess pathologic findings, personal and family history of BHD manifestations, referral for genetic evaluation, and genetic testing results. Results: 64 patients had a pathologic diagnosis of TD or FF, 16 of whom (25%) were referred to cancer genetics. Fourteen patients completed genetic evaluation, 9 of whom were diagnosed with BHD (64%), with 6 unique pathogenic variants in FLCN. Conclusion: Providers should consider referral for genetic evaluation for patients with biopsy-proven TD or FF, as early diagnosis of BHD provides the opportunity for early detection and treatment of other BHD-associated conditions. Capsule Summary: • Birt-Hogg-Dube syndrome includes renal cancer, pneumothorax, and trichodiscomas and fibrofolliculomas and is caused by pathogenic variants in FLCN. • Patients with trichodiscoma or fibrofolliculoma should be considered for referral to cancer genetics to allow identification of pathogenic FLCN variants and thus family cascade testing and surveillance for renal tumors. [ABSTRACT FROM AUTHOR]

Background: Buyang Huanwu decoction (BHD) is a traditional Chinese medicine herbal formula used for treating hypertension, particularly in the later stages of hypertension when it is associated with intracerebral hemorrhage. This study aims to investigate the treatment mechanism of BHD to provide a basis for its clinical application in hypertension treatment. Methods: Network pharmacology analysis and cell culture experiments were performed to explore the potential proteins and mechanisms of action of BHD against hypertension. Bioactive compounds related to BHD were screened, and relevant targets associated with hypertension and BHD were retrieved. Molecular docking technology was used to identify the effective signaling pathway based on the Kyoto Encyclopedia of Genes and Genomes and protein-protein interaction network cores. Lastly, the effects and mechanisms of BHD on salt-sensitive hypertensive endothelial cells were investigated. Results: Ninety-three potential therapeutic targets for BHD and salt-sensitive hypertension were found to be closely associated with the PI3K/Akt/eNOS signaling pathway and oxidative stress. Cell experiments further indicated the pivotal role of endothelial cells in hypertension, and validation analysis showed that BHD significantly preserved cell morphology, suppressed oxidative stress reactions, activated the PI3K/Akt/eNOS signaling pathways, preserved normal endothelial cell function, and reduced cell apoptosis. Conclusion: BHD effectively activates the PI3K/Akt/VEGF signaling pathway, attenuates oxidative stress-induced injury in endothelial cells exposed to high salt levels, and mitigates apoptosis, supporting the use of traditional Chinese medicine BHD in the treatment of salt-sensitive hypertension. [ABSTRACT FROM AUTHOR]

Basic Life Support (BHD) is very important since it teaches how to provide basic daily life support techniques that are commonly encountered. This community service program intends to provide education as well as training to youth organizations and health cadres of the village who partners with the Community Service Institute of Universitas Muhammadiyah Yogyakarta, namely hamlets of Sribit and Sekarsuli, Berbah, Sleman. The model of the BHD training program was a combination of mini-lecture and practice. Technically, BHD materials were taught by the health professionals to participants 8 times in 1 month. Determination the effectiveness of the program, pretest and posttest were conducted before and after the training. The statistical analysis test results for the total value of the pretest and posttest found that there was an increase in the total of respondents (n=23) who had a good average level of knowledge, from 0 (0%) to 14 (60.8%). The average value of the test also increased, i.e. before the program was 46.13 then became 80.43, with a p value of 0.001 using the Wilcoxon test. This indicated that there is a difference in the respondents’ knowledge before and after conducting basic BHD training. The implication of this program was that the combination of mini lectures and practice could be utilized as an effective approach in providing education and training on BHD for lay people.

Abstract Birt‐Hogg‐Dubé (BHD) syndrome is an inherited familial cancer syndrome characterized by the development of cutaneous lesions, pulmonary cysts, renal tumors and cysts and caused by loss‐of‐function pathogenic variants in the gene encoding the tumor‐suppressor protein folliculin (FLCN). FLCN acts as a negative regulator of TFEB and TFE3 transcription factors, master controllers of lysosomal biogenesis and autophagy, by enabling their phosphorylation by the mechanistic Target Of Rapamycin Complex 1 (mTORC1). We have previously shown that deletion of Tfeb rescued the renal cystic phenotype of kidney‐specific Flcn KO mice. Using Flcn/Tfeb/Tfe3 double and triple KO mice, we now show that both Tfeb and Tfe3 contribute, in a differential and cooperative manner, to kidney cystogenesis. Remarkably, the analysis of BHD patient‐derived tumor samples revealed increased activation of TFEB/TFE3‐mediated transcriptional program and silencing either of the two genes rescued tumorigenesis in human BHD renal tumor cell line‐derived xenografts (CDXs). Our findings demonstrate in disease‐relevant models that both TFEB and TFE3 are key drivers of renal tumorigenesis and suggest novel therapeutic strategies based on the inhibition of these transcription factors.

A number of germline syndromes that predispose affected individuals to develop renal cancer have been described, each with unique manifestations, histopathology, and tumor behavior. Patients tend to present with early onset and/or multifocal tumors. Familiarity with these syndromes helps to identify at-risk patients and recommend genetic screening. Early detection is essential to direct appropriate cancer surveillance protocols for patients and other family members and care strategies that preserve lifelong renal function while minimizing risk of death from metastatic cancer.

Birt‐Hogg‐Dubé (BHD) syndrome is an inherited familial cancer syndrome characterized by the development of cutaneous lesions, pulmonary cysts, renal tumors and cysts and caused by loss‐of‐function pathogenic variants in the gene encoding the tumor‐suppressor protein folliculin (FLCN). FLCN acts as a negative regulator of TFEB and TFE3 transcription factors, master controllers of lysosomal biogenesis and autophagy, by enabling their phosphorylation by the mechanistic Target Of Rapamycin Complex 1 (mTORC1). We have previously shown that deletion of Tfeb rescued the renal cystic phenotype of kidney‐specific Flcn KO mice. Using Flcn/Tfeb/Tfe3 double and triple KO mice, we now show that both Tfeb and Tfe3 contribute, in a differential and cooperative manner, to kidney cystogenesis. Remarkably, the analysis of BHD patient‐derived tumor samples revealed increased activation of TFEB/TFE3‐mediated transcriptional program and silencing either of the two genes rescued tumorigenesis in human BHD renal tumor cell line‐derived xenografts (CDXs). Our findings demonstrate in disease‐relevant models that both TFEB and TFE3 are key drivers of renal tumorigenesis and suggest novel therapeutic strategies based on the inhibition of these transcription factors. Synopsis: TFEB and TFE3 transcription factors are master regulators of cell metabolism. This study shows that in Birt‐Hogg‐Dubé (BHD) hereditary cancer syndrome, these factors concomitantly activate cellular catabolic and anabolic pathways, playing a key role in kidney cystogenesis and tumorigenesis. Genetic interaction studies revealed that TFEB and TFE3 have a differential and cooperative role in the kidney phenotype of a mouse model of BHD syndrome.Transcriptomic and proteomic analyses of tumor samples from BHD patients showed upregulation of the TFEB/TFE3 transcriptional program and induction of both lysosomal and mTORC1 pathways.Depletion of TFEB or TFE3 fully abrogated the growth of BHD renal tumor cells in xenograft experiments, indicating that both genes are key drivers of tumorigenesis. [ABSTRACT FROM AUTHOR]

Abstract Background Birt-Hogg-Dubé syndrome (BHD) is an inherited disease caused by pathogenic variants in the FLCN gene. One of the characteristics is the increased risk for spontaneous pneumothorax, likely due to the presence of pulmonary cysts mainly distributed under the carina. Due to variable expression and lack of awareness, BHD is likely to be underdiagnosed. We aimed to examine the prevalence of BHD in patients presenting with an apparent primary spontaneous pneumothorax and to evaluate the contribution of chest CT in establishing the diagnosis. Methods Patients who presented with apparent primary spontaneous pneumothorax between 2004 and 2017 in a large Dutch teaching hospital were enrolled in this quantitative cross-sectional study. A questionnaire was sent to eligible patients. Patients who completed the questionnaire and consented to further participation were invited to visit the hospital for genetic testing and low dose, volumetric chest CT. Results Genetic testing was performed in 88 patients with apparent primary spontaneous pneumothorax. Three patients were found to have a pathogenic variant in the FLCN gene (3.4%). No variants of unknown significance were detected. Pulmonary cysts were detected in 14 out of 83 participants with an available chest CT, six had more than one cyst. All three patients with BHD had multiple pulmonary cysts. Conclusions Based on previous literature and the present study, we believe that performing a chest CT in every patient presenting with primary spontaneous pneumothorax is justified. Subsequent genetic testing of the FLCN gene should be considered when multiple pulmonary cysts are present. Trial registration The study was registered at clinicaltrials.gov with reference NCT02916992. Summary at a glance Three out of 88 patients with an apparent primary spontaneous pneumothorax were diagnosed with Birt-Hogg-Dubé syndrome in this study and all three had multiple pulmonary cysts. We believe that performing a chest CT in every patient with an apparent primary spontaneous pneumothorax is justified to identify underlying diseases.

Background: Birt-Hogg-Dubé syndrome (BHD) is an inherited disease caused by pathogenic variants in the FLCN gene. One of the characteristics is the increased risk for spontaneous pneumothorax, likely due to the presence of pulmonary cysts mainly distributed under the carina. Due to variable expression and lack of awareness, BHD is likely to be underdiagnosed. We aimed to examine the prevalence of BHD in patients presenting with an apparent primary spontaneous pneumothorax and to evaluate the contribution of chest CT in establishing the diagnosis.Methods: Patients who presented with apparent primary spontaneous pneumothorax between 2004 and 2017 in a large Dutch teaching hospital were enrolled in this quantitative cross-sectional study. A questionnaire was sent to eligible patients. Patients who completed the questionnaire and consented to further participation were invited to visit the hospital for genetic testing and low dose, volumetric chest CT.Results: Genetic testing was performed in 88 patients with apparent primary spontaneous pneumothorax. Three patients were found to have a pathogenic variant in the FLCN gene (3.4%). No variants of unknown significance were detected. Pulmonary cysts were detected in 14 out of 83 participants with an available chest CT, six had more than one cyst. All three patients with BHD had multiple pulmonary cysts.Conclusions: Based on previous literature and the present study, we believe that performing a chest CT in every patient presenting with primary spontaneous pneumothorax is justified. Subsequent genetic testing of the FLCN gene should be considered when multiple pulmonary cysts are present.Trial Registration: The study was registered at clinicaltrials.gov with reference NCT02916992. Three out of 88 patients with an apparent primary spontaneous pneumothorax were diagnosed with Birt-Hogg-Dubé syndrome in this study and all three had multiple pulmonary cysts. We believe that performing a chest CT in every patient with an apparent primary spontaneous pneumothorax is justified to identify underlying diseases. [ABSTRACT FROM AUTHOR]

Background: To our knowledge, this is the first report of patient with BHD syndrome caused by a novel mutation in the FLCN gene who developed a cerebral venous sinus thrombosis(CVST). Case presentation: A 62-year-old male patient with a history of hypertension and two case of spontaneous pneumothorax. He had a 1-month history of headache and was admitted to the hospital one day after the headache aggravated. The patient had a family history of BHD syndrome which was confirmed by FLCN gene sequencing. Sequencing analysis revealed a novel nonsense mutation (NM_144997; c.607A > T; p.Lys203Ter) in the FLCN gene exon 6 of the patient, which was proved to be a pathogenetic mutation by pedigree verification. BHD syndrome was finally definitive diagnosis. Low molecular weight heparin (21 days) was given for anticoagulant therapy before and after resection of renal tumor which is confirmed to be clear cell carcinoma in the kidney. After discharge, warfarin was given for anticoagulant therapy (6 months). Conclusions: There was no recurrence of CVST. And no recurrence of tumor and new renal tumor were found in renal MRI examination after 6 months. [ABSTRACT FROM AUTHOR]

Thailand has recently implemented the Alternative Energy Development Plan (2015–2036) aiming to reduce the dependency on conventional fuels, notably diesel from oil palm. To ensure sustainability of substituting diesel, this study aims to assess the environmental effects of three promising biofuels namely, conventional biodiesel or Fatty acid methyl ester (FAME), Bio-hydrogenated diesel (BHD) and the newest alternative fuel, Partially Hydrogenated Fatty Acid Methyl Ester (H-FAME) compared to diesel in transport sector. The system boundary is “Well-to-Wheels. This study does not show a significant difference in the energy performances and environmental effects of the studied biofuels. The partial substitution of diesel by FAME, H-FAME and BHD can decrease fossil use and greenhouse gas (GHG) emissions significantly. In terms of global warming potential GWP, more than 100 million tonnes CO 2 eq would be reduced in the next 20 years according to the projection of 25% replaced conventional diesel consumption. To improve the performance in terms of resource use and GHG mitigation, the study results suggest encouraging the use of H-FAME and BHD as a good choice. Both these alternative fuels can be blended with conventional diesel more than 2 times compared with FAME. In the initial stage, substitution could start with implementing H-FAME and slightly reduce the use of FAME after which BHD could be implemented along with FAMEand H-FAME. [ABSTRACT FROM AUTHOR]

This study encompasses the pathology both gross and microscopic, of a recent outbreak of Leucocytozoon caulleryi infection in a commercial broiler flock. Four numbers of 3 3-day-old broilers {Gallus gallus domesticus) were necropsied following a history of depression and sudden death. On necropsy, subcutaneous haemorrhages were observed in the pectoral and thigh muscles, epicardium, pancreas, and kidneys. On histopathology, numerous schizonts, megaloschizonts and merozoites of Leucocytozoon were observed in the heart, liver, lung, kidneys, thymus and bursa of Fabricius. Although L. caulleryi infection was diagnosed previously in Kerala, there are no reports of an outbreak of L. caulleryi in broiler chicken in the state. [ABSTRACT FROM AUTHOR]

Renal cell cancer (RCC) represents 2-3 % of all cancers and is the most lethal of the urologic malignancies, in a minority of cases caused by a genetic predisposition. Birt-Hogg-Dubé syndrome (BHD) is one of the hereditary renal cancer syndromes. As the histological subtype and clinical presentation in BHD are highly variable, this syndrome is easily missed. Lung cysts-mainly under the main carina-are reported to be present in over 90 % of all BHD patients and might be an important clue in differentiating between sporadic RCC and BHD associated RCC. We conducted a retrospective study among patients diagnosed with sporadic RCC, wherein we retrospectively scored for the presence of lung cysts on thoracic CT. We performed FLCN mutation analysis in 8 RCC patients with at least one lung cysts under the carina. No mutations were identified. We compared the radiological findings in the FLCN negative patients to those in 4 known BHD patients and found multiple basal lung cysts were present significantly more frequent in FLCN mutation carriers and may be an indication for BHD syndrome in apparent sporadic RCC patients. [ABSTRACT FROM AUTHOR]

Germline mutation of the FLCN gene causes Birt-Hogg-Dubé syndrome (BHD), a rare autosomal dominant condition characterized by skin fibrofolliculomas, lung cysts, spontaneous pneumothorax and renal tumours. We identified a hitherto unreported pathogenic FLCN frameshift deletion c.563delT (p.Phe188Serfs*35) in a family of a 46-year-old woman presented with macrohematuria due to bilateral chromophobe renal carcinomas. A heritable renal cancer was suspected due to the bilaterality of the tumour and as the father of this woman had suffered from renal cancer. Initially, however, BHD was overlooked by the medical team despite the highly suggestive clinical presentation. We assume that BHD is underdiagnosed, at least partially, due to low awareness of this variable condition and to insufficient use of appropriate genetic testing. Our study indicates that BHD and FLCN testing should be routinely considered in patients with positive family or personal history of renal tumours. In addition, we demonstrate how patients and their families can play a driving role in initiating genetic diagnosis, presymptomatic testing of at-risk relatives, targeted disease management, and genetic counselling of rare diseases such as BHD. [ABSTRACT FROM AUTHOR]

Mammalian skeletal muscle is broadly characterized by the presence of two distinct categories of muscle fibers called type I "red" slow twitch and type II "white" fast twitch, which display marked differences in contraction strength, metabolic strategies, and susceptibility tofatigue. The relative representation of each fiber type can have major influences on susceptibility to obesity, diabetes, and muscular dystrophies. However, the molecular factors controlling fiber type specification remain incompletely defined. In this study, we describe the control of fiber type specification and susceptibility to metabolic disease by folliculin interacting protein-1 (Fnip1). Using Fnip1 null mice, we found that loss of Fnip1 increased the representation of type I fibers characterized by increased myoglobin, slow twitch markers [myosin heavy chain 7 (MyH7), succinate dehydrogenase, troponin I 1, troponin C1, troponin T1], capillary density, and mitochondria number. Cultured Fnip1-null muscle fibers had higher oxidative capacity, and isolated Fnip1-null skeletal muscles were more resistant to postcontraction fatigue relative to WT skeletal muscles. Biochemical analyses revealed increased activation of the metabolic sensor AMP kinase (AMPK), and increased expression of the AMPK-target and transcriptional coactivator PGC1α in Fnip1 null skeletal muscle. Genetic disruption of PGC1α rescued normal levels of type I fiber markers MyH7 and myoglobin in Fnip1-null mice. Remarkably, loss of Fnip1 profoundly mitigated muscle damage in a murine model of Duchenne muscular dystrophy. These results indicate that Fnip1 controls skeletal muscle fiber type specification and warrant further study to determine whether inhibition of Fnip1 has therapeutic potential in muscular dystrophy diseases. [ABSTRACT FROM AUTHOR]

Germline loss-of-function BHD mutations cause cystic lung disease and hereditary pneumothorax, yet little is known about the impact of BHD mutations in the lung. Folliculin (FLCN), the product of the Birt-Hogg-Dube (BHD) gene, has been linked to altered cell-cell adhesion and to the AMPK and mTORC1 signaling pathways. We found that downregulation of FLCN in human bronchial epithelial (HBE) cells decreased the phosphorylation of ACC, a marker of AMPK activation, while downregulation of FLCN in small airway epithelial (SAEC) cells increased the activity of phospho-S6, a marker of mTORC1 activation, highlighting the cell type-dependent functions of FLCN. Cell-cell adhesion forces were significantly increased in FLCN-deficient HBE cells, consistent with prior findings in FLCN-deficient human kidney-derived cells. To determine how these altered cell-cell adhesion forces impact the lung, we exposed mice with heterozygous inactivation of Bhd (similarly to humans with germline inactivation of one BHD allele) to mechanical ventilation at high tidal volumes. Bhd+/− mice exhibited a trend ( P = 0.08) toward increased elastance after 6 h of ventilation at 24 cc/kg. Our results indicate that FLCN regulates the AMPK and mTORC1 pathways and cell-cell adhesion in a cell type-dependent manner. FLCN deficiency may impact the physiologic response to inflation-induced mechanical stress, but further investigation is required. We hypothesize that FLCN-dependent effects on signaling and cellular adhesion contribute to the pathogenesis of cystic lung disease in BHD patients. [ABSTRACT FROM AUTHOR]

Background: Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominantly inherited disorder caused by germline mutations in the folliculin (FLCN) gene. Clinical manifestations of BHD include skin fibrofolliculomas, renal cell cancer, lung cysts and (recurrent) spontaneous pneumothorax (SP). All clinical manifestations usually present in adults > 20 years of age. Case presentations: Two non-related patients with (recurrent) pneumothorax starting at age 14 accompanied by multiple basal lung cysts on thoracic CT underwent FLCN germline mutation analysis. A pathogenic FLCN mutation was found in both patients confirming suspected BHD. The family history was negative for spontaneous pneumothorax in both families. Conclusion: Although childhood occurrence of SP in BHD is rare, these two cases illustrate that BHD should be considered as cause of SP in children. [ABSTRACT FROM AUTHOR]

Since the hallmark dermatologic features of Birt-Hogg-Dubé (BHD) syndrome were first described by three Canadian physicians in 1977, the clinical manifestations of BHD have been expanded to include hamartomas of the hair follicle, lung cysts, increased risk for spontaneous pneumothorax and kidney neoplasia. Twenty-five years later the causative gene FLCN was identified, and the mutation spectrum has now been defined to include mainly protein truncating mutations, but also rare missense mutations and large gene deletions/duplication. Second 'hit' FLCN mutations in BHD kidney tumors and loss of tumorigenic potential of the FLCN-null UOK257 tumor cell line when FLCN is re-expressed underscore a tumor suppressor role for FLCN. The identification of novel FLCN interacting proteins FNIP1 and FNIP2/L and their interaction with 5′-AMP activated protein kinase (AMPK) has provided a link between FLCN and the AMPK-mTOR axis and suggested molecular targets for therapeutic intervention to treat BHD kidney cancer and fibrofolliculomas. The generation of FLCN-null cell lines and in vivo animal models in which FLCN (or FNIP1) has been inactivated have provided critical reagents to facilitate mechanistic studies of FLCN function. Research efforts utilizing these critical FLCN-deficient cell lines and mice have begun to uncover important signaling pathways in which FLCN and its protein partners may play a role, including TGF-β signaling, TFE3 transcriptional regulation, PGC1-α driven mitochondrial biogenesis, apoptotic response to cell stress, and vesicular transport. As the mechanisms by which FLCN inactivation leads to BHD manifestations are clarified, we can begin to develop therapeutic agents that target the pathways dysregulated in FLCN-deficient fibrofolliculomas and kidney tumors, providing improved prognosis and quality of life for BHD patients. [ABSTRACT FROM AUTHOR]

In addition to the associated cutaneous and pulmonary manifestations, individuals with the Birt-Hogg-Dubé (BHD) syndrome have an increased risk of developing kidney cancer, which is often bilateral and multifocal. The risk of developing a renal tumor in this population does not decrease with age and therefore warrants a lifelong screening approach. We recommend abdominal imaging every 36 months in individuals without renal lesions at initial screening. Once renal tumors are identified, they should be followed with interval imaging studies until the largest tumor reaches 3 cm in maximal diameter, at which point nephron-sparing surgery should be ideally pursued. While the histology of renal tumors can vary in the BHD syndrome, most tumors possess a relatively indolent natural history and do not require adjuvant therapy if resected when localized to the kidney. With this approach, the vast majority of patients will achieve a curative oncologic outcome and avoid the medical sequelae of chronic renal insufficiency that could otherwise result from total nephrectomy. [ABSTRACT FROM AUTHOR]

Background Paclitaxel, a widely used chemotherapeutic drug, can induce apoptosis in variety of cancer cells. A previous study has shown preferential toxicity of paclitaxel to FLCN-deficient kidney cancer cell line, UOK257. In this report, we investigate the cellular and molecular mechanism of paclitaxel-induced autophagy and apoptosis in renal cancer cells with and without FLCN expression Methods Two pairs of cell lines were used: FLCN siRNA-silenced ACHN cell line (ACHN-5968) and scrambled ACHN cell line (ACHN-sc); FLCN-null UOK257 cell line and UOK257-2 cell line restored with ectopic expression of FLCN. Autophagy was examined by western blot, GFP-LC3, transmission electron microscopy, and MDC assay. Cell viability and apoptosis were detected using MTT assay, DAPI stain and TUNEL assay. After inhibition of autophagy with 3-Methyladenine (3-MA) or Beclin 1 siRNA, cell viability and apoptosis were measured by MTT assay and TUNEL assay. Results After paclitaxel treatment, a dose-dependent decrease in cell viability and increase in apoptosis were observed in FLCN-deficient UOK257 and ACHN-5968 cells compared to their FLCN-expressing counterparts, suggesting that renal cancer cells without FLCN were more sensitive to paclitaxel. Enhanced autophagy was found to be associated with paclitaxel treatment in FLCN-deficient RCC cells. The MAPK pathway was also identified as a key pathway for the activation of autophagy in these kidney cancer cells. Inhibition of phosphorylated ERK with ERK inhibitor UO126 showed a significant decrease in autophagy. Furthermore, after inhibition of autophagy with 3-Methyladenine (3-MA) or Beclin 1 siRNA, apoptosis induced by paclitaxel was significantly increased in FLCN-deficient UOK257 and ACHN-5968 cells. Conclusions Preferential toxicity of paclitaxel to FLCN-deficient kidney cancer cells is associated with enhanced autophagy. Suppression of autophagy further enhances paclitaxel-induced apoptosis in FLCN-deficient renal cancer cells. Our results suggest that paclitaxel combined with an autophagy inhibitor might be a potentially more effective chemotherapeutic approach for FLCN-deficient renal cancer. [ABSTRACT FROM AUTHOR]

Kidney cancer is a heterogeneous disease comprised of a number of histologic subtypes, each associated with unique genetic mutations, clinical features, and sensitivity to treatment. By examining families affected with the hereditary kidney cancer syndromes von Hippel-Lindau, hereditary papillary renal cell carcinoma, hereditary leiomyomatosis and renal cell carcinoma, and Birt-Hogg-Dubé, researchers have been able to identify the genes responsible for these syndromes. This work has revealed that kidney cancer is fundamentally a metabolic disorder, and as such, novel targeted therapies specific to their molecular biology have been developed and employed in both the hereditary and sporadic forms of renal cell carcinoma. [ABSTRACT FROM AUTHOR]

Kidney cancer is not a single disease; it is made up of a number of cancers that occur in the kidney, each having a different histology, following a different clinical course, responding differently to therapy, and caused by a different gene. Study of the genes underlying kidney cancer has revealed that it is fundamentally a metabolic disorder. Understanding the genetic basis of cancer of the kidney has significant implications for diagnosis and management of this disease. VHL is the gene for clear cell kidney cancer. The VHL protein forms a complex that targets the hypoxia-inducible factors for ubiquitin-mediated degradation. Knowledge of this pathway provided the foundation for the development of novel therapeutic approaches now approved for treatment of this disease. MET is the gene for the hereditary form of type 1 papillary renal carcinoma and is mutated in a subset of sporadic type 1 papillary kidney cancers. Clinical trials are currently ongoing with agents targeting the tyrosine kinase domain of MET in sporadic and hereditary forms of papillary kidney cancer. BHD is the gene for the hereditary type of chromophobe kidney cancer. It is thought to be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways. Hereditary Ieiomyomatosis renal cell carcinoma, a hereditary form of type 2 papillary renal carcinoma, is caused by inactivation of a Krebs cycle enzyme due to mutation. Knowledge of these kidney cancer gene pathways has enabled new approaches in the management of this disease and has provided the foundation for the development of targeted therapeutics. [ABSTRACT FROM AUTHOR]

Abstract: The Birt–Hogg–Dubé gene (BHD) encodes the tumor suppressor protein folliculin (FLCN). The function of FLCN has recently been implicated in the regulation of rapamycin-sensitive mTOR complex (mTORC1). Reciprocally, the mTORC1-dependent phosphorylation of FLCN was reported. However, precise mechanism of FLCN phosphorylation and functional interaction of FLCN with tuberin, the product of tuberous sclerosis 2 gene (TSC2) which is a negative regulator of mTORC1, are unclear. Here we report that multiple phosphorylation in FLCN are evoked by downregulation of tuberin as well as by Rheb expression. We found that phosphorylation at Ser62 and Ser302 are differently regulated by mTORC1-dependent pathway. Some unknown kinases downstream of tuberin-mTORC1 are thought to directly phosphorylate FLCN. Interestingly, our results also suggest that the complex formation of FLCN with AMPK is modulated by FLCN phosphorylation. These results suggest that FLCN is involved in a novel mechanism of signal transduction downstream of tuberin. [Copyright &y& Elsevier]

Birt–Hogg–Dubé (BHD) syndrome is a tumor-suppressor gene disorder characterized by skin tumors, cystic lung disease and renal cell carcinoma. Very little is known about the molecular pathogenesis of BHD. Clinical similarities between BHD and tuberous sclerosis complex (TSC) suggest that the BHD and TSC proteins may function within a common pathway. The TSC proteins inhibit the activity of the mammalian target of rapamycin complex 1 (TORC1), and in Schizosaccharomyces pombe, Bhd and Tsc1/Tsc2 have opposing roles in the regulation of amino-acid homeostasis. We report here that in mammalian cells, downregulation of BHD reduces the phosphorylation of ribosomal protein S6, an indicator of TORC1 activity. To determine whether folliculin, the product of the BHD gene, regulates mammalian target of rapamycin activity in vivo, we generated a mouse with targeted inactivation of the Bhd gene. The mice developed spontaneous oncocytic cysts and tumors composed of cells that resemble the renal cell carcinomas in BHD patients. The cysts and tumors had low levels of phospho-S6. Taken together, these data indicate that folliculin regulates the activity of TORC1, and suggest a new paradigm in which both inappropriately high and inappropriately low levels of TORC1 activity can be associated with renal tumorigenesis.Oncogene (2009) 28, 1594–1604; doi:10.1038/onc.2009.14; published online 23 February 2009 [ABSTRACT FROM AUTHOR]

Abstract: Over the last several decades, the advances in molecular genetics have elucidated kidney cancer gene pathways. Kidney cancer is a heterogeneous disorder. Each specific type of kidney cancer has its own histologic features, gene, and clinical course. Insight into the genetic basis of kidney cancer has been learned largely from the study of the familial or hereditary forms of kidney cancer. Extirpative surgery is currently the treatment of choice for kidney cancer that is confined to the kidney. Treatment for advanced or metastatic kidney cancer is a formidable challenge with the traditional therapies currently available. However, investigation of the Mendelian single-gene syndromes, like von Hippel Lindau (VHL: VHL gene), hereditary papillary renal carcinoma (HPRC: c-Met gene), Birt-Hogg-Dubé (BHD: BHD gene), and hereditary leiomyomatosis renal cell cancer (HLRCC: fumarate hydratase gene) provides an opportunity to develop pathway specific therapies. Advances in molecular therapeutics offer novel treatment options for patients with advanced disease. [Copyright &y& Elsevier]

Abstract: Renal-cell cancer (RCC) is an heterogeneous disease consisting of different subtypes that show peculiar histological features and genetic alterations. Although inherited or familial predisposition occurs in less than 4% of renal cancers, most of the available information on the genetic alterations involved in the pathogenesis of RCC derives from the study of the inherited forms of kidney cancer: von Hippel-Lindau (VHL gene), hereditary papillary renal carcinoma (MET proto-oncogene), hereditary leiomyomatosis and renal-cell cancer (fumarate hydratase gene), and Birt–Hogg–Dube (BHD gene) syndromes. Such genetic alterations have also been detected in sporadic RCCs. In particular, inactivation of VHL gene by mutation or hypermethylation has been found in up to 70% of sporadic clear-cell RCC, and it has been associated with increased hypoxia-inducible factor (HIF) activity. The knowledge of these deregulated genes and their downstream pathways provides the rationale for the development of target-based approaches for RCC. [Copyright &y& Elsevier]

Birt-Hogg-Dubé (BHD) syndrome is characterized by the development of pneumothorax, hair folliculomas and renal tumors and the responsible BHD gene is thought to be a tumor suppressor. The function of folliculin (Flcn), encoded by BHD, is totally unknown, although its interaction with Fnip1 has been reported. In this study, we identified a novel protein binding to Flcn, which is highly homologous to Fnip1, and which we named FnipL (recently reported in an independent study as Fnip2). The interaction between FnipL/Fnip2 and Flcn may be mediated mainly by the C-terminal domains of each protein as is the case for the Flcn-Fnip1 interaction. FnipL/Fnip2 and Flcn were located together in the cytoplasm in a reticular pattern, although solely expressed Flcn was found mainly in the nucleus. Cytoplasmic retention of Flcn was canceled with C-terminal truncation of FnipL/Fnip2, suggesting that FnipL/Fnip2 regulates Flcn distribution through their complex formation. By the employment of siRNA, we observed a decrease in S6K1 phosphorylation in the BHD-suppressed cell. We also observed a decrease in S6K1 phosphorylation in FNIP1- and, to a lesser extent, in FNIPL/FNIP2-suppressed cells. These results suggest that Flcn-FnipL/Fnip2 and Flcn-Fnip1 complexes positively regulate S6K1 phosphorylation and that FnipL/Fnip2 provides an important clue to elucidating the function of Flcn and the pathogenesis of BHD.Oncogene (2008) 27, 5339–5347; doi:10.1038/onc.2008.261; published online 28 July 2008 [ABSTRACT FROM AUTHOR]

Abstract: Birt–Hogg–Dube'' syndrome characterized by increased risk for renal neoplasia is caused by germline mutations in the BHD/FLCN gene encoding a novel tumor suppressor protein, folliculin(FLCN), which interacts with FNIP1 and 5′-AMP-activated protein kinase(AMPK). Here we report the identification and characterization of a novel FNIP1 homolog FNIP2 that also interacts with FLCN and AMPK. C-terminally-deleted FLCN mutants, similar to those produced by naturally-occurring germline mutations in BHD patients, were unable to bind FNIP2. These data taken together with our previous results that demonstrated FNIP1 binding to the C-terminus of FLCN suggest that FLCN tumor suppressor function may be facilitated by interactions with both FNIP1 and FNIP2 through its C-terminus. Furthermore, we demonstrate that FNIP1 and FNIP2 are able to form homo- or heteromeric multimers suggesting that they may function independently or cooperatively with FLCN. Differential expression of FNIP1 and FNIP2 transcripts in some normal tissues may indicate tissue specificity for these homologs. Interestingly FNIP1 and FNIP2 were oppositely expressed in human clear cell renal cell carcinoma (RCC), and coordinately expressed in chromophobe RCC and oncocytoma, suggesting their differential function in different histologic variants of RCC. [Copyright &y& Elsevier]

Abstract: Fibromatosis-type fibromas were found to develop at abdominal surgical sites in 4 heterozygous Nihon rats, a model for the human Birt–Hogg–Dubé syndrome. In all 4 rats, solitary and firm nodules were located within the lateral abdominal musculature involving the full thickness of the abdominal wall at the sites of laparotomy. Histologically, the nodules consisted of well-differentiated fibroblastic spindle-shaped cells. These cells were surrounded by large amounts of collagen fibers, and appeared to infiltrate within the abdominal musculature. A portion of the spindle-shaped cells showed features of myofibroblasts. These characteristics are consistent with desmoid tumors in human. Although the etiology of desmoid tumors in human remains unclear, they are known to occur in association with hormonal factors, surgical trauma, and familial adenomatous polyposis. In animals, they have been reported in dogs, cats, horses, and genetically modified mouse models for human familial adenomatous polyposis. The development of the tumors in the Nihon rats was apparently associated with surgical incisions. Genetic factor should be involved in the occurrence of the tumor, since it was found only in the Nihon rats among many rats. Our present data suggest that Bhd gene mutation is not likely to be a candidate. [Copyright &y& Elsevier]

BHD, TP53, and HNF1β on chromosome 17 were studied in 92 cases of renal cell carcinoma (46 chromophobe, 19 clear cell, 18 oncocytoma, and nine papillary). Six, thirteen, and zero cases had, respectively BHD, TP53, and HNF1β mutations, (84% mutations involved chromophobe), suggesting a role for BHD and TP53 in chromophobe subtype.British Journal of Cancer (2007) 96, 336–340. doi:10.1038/sj.bjc.6603492 www.bjcancer.com Published online 28 November 2006 [ABSTRACT FROM AUTHOR]

Focuses on the studies of familial tumors using genotype, phenotype, and dramatype in carcinogenesis. Gene mutation in multistep renal carcinogenesis; Comparison between second hit in spontaneously induced, chemically induced, and radiation-induced renal carcinogenesis in Tsc 2 gene mutant model; Prevention of carcinogenesis by interferon.

We report on a child with two cardiac rhabdomyomas. Initially, a diagnosis of Tuberous Sclerosis Complex (TSC) syndrome was suspected, although this could neither be confirmed clinically nor genetically. Coincidentally, Birt Hogg Dubé syndrome (BHD) had been previously diagnosed in members of the extended family; this prompted a diagnostic re-evaluation of the child who was found to have the known family FLCN mutation. We recommend consideration of cardiac rhabdomyomas as part of the clinical BHD spectrum. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract Resources for rare diseases are lacking. Patients do not have the information and support that they need, and researchers struggle to make progress due to a shortage of skills and collaborations within the field. One way to overcome these hurdles is to host annual Symposia, focused on a specific rare disease. Here, we use the example of Birt-Hogg-Dubé Symposia to discuss the practical issues of such meetings, including the importance of timing and the choice of invited speakers. We highlight the ways in which rare disease symposia can create a single community, removing barriers between patients, clinicians and researchers.

Birt-Hogg-Dubé (BHD) syndrome is a multiorgan disorder caused by inactivation of the folliculin (FLCN) protein. Previously, we identified FLCN as a binding protein of Rab11A, a key regulator of the endocytic recycling pathway. This finding implies that the abnormal localization of specific proteins whose transport requires the FLCN-Rab11A complex may contribute to BHD. Here, we used human kidney-derived HEK293 cells as a model, and we report that FLCN promotes the binding of Rab11A with transferrin receptor 1 (TfR1), which is required for iron uptake through continuous trafficking between the cell surface and the cytoplasm. Loss of FLCN attenuated the Rab11A-TfR1 interaction, resulting in delayed recycling transport of TfR1. This delay caused an iron deficiency condition that induced hypoxia-inducible factor (HIF) activity, which was reversed by iron supplementation. In a Drosophila model of BHD syndrome, we further demonstrated that the phenotype of BHD mutant larvae was substantially rescued by an iron-rich diet. These findings reveal a conserved function of FLCN in iron metabolism and may help to elucidate the mechanisms driving BHD syndrome., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Brit-Hogg-Dubé syndrome (BHD) is a rare disorder that is estimated to affects about 600 families in the World. The disease-causing mutations is on FLCN gene which codes for folliculin. This protein has a role in different organs as skin, kidney and lung, thanks to the interaction with type I and II cadherins, RhoA activity and the regulation of AMPK, mTORC1 pathways and cell adhesion. The aim of our study is to focus on the manifestation of the syndrome, especially the pulmonary involvement, then on genetical analysis and on the available treatments., Material and Methods: We collected 15 previous studies where we found medical history information, clinical manifestations, radiological and histological diagnosis and genetical analysis., Results: The prevalence of pneumothorax in patients with BHD syndrome was about 65%, but the lung involvement with multiple small cysts, localized especially in the lower part, was 85%. The prevalence of renal involvement in BHD patients ranged from 6.5% to 34%, while skin lesions ranged from 11% to 50%. More than 150 FLCN germline has been described, though the mutation in exon 11 is the most frequently detected, especially among Caucasian population., Conclusions: BHD syndrome is rare and usually the first manifestations appear in early age. In patients with these clinical and radiological characteristics we suggest taking a careful medical history, though the diagnosis of BHD syndrome should be confirmed with the analysis of FLCN gene., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Summary The molecular chaperone Hsp90 stabilizes and activates client proteins. Co-chaperones and post-translational modifications tightly regulate Hsp90 function and consequently lead to activation of clients. However, it is unclear whether this process occurs abruptly or gradually in the cellular context. We show that casein kinase-2 phosphorylation of the co-chaperone folliculin-interacting protein 1 (FNIP1) on priming serine-938 and subsequent relay phosphorylation on serine-939, 941, 946, and 948 promotes its gradual interaction with Hsp90. This leads to incremental inhibition of Hsp90 ATPase activity and gradual activation of both kinase and non-kinase clients. We further demonstrate that serine/threonine protein phosphatase 5 (PP5) dephosphorylates FNIP1, allowing the addition of O -GlcNAc (O -linked N-acetylglucosamine) to the priming serine-938. This process antagonizes phosphorylation of FNIP1, preventing its interaction with Hsp90, and consequently promotes FNIP1 lysine-1119 ubiquitination and proteasomal degradation. These findings provide a mechanism for gradual activation of the client proteins through intricate crosstalk of post-translational modifications of the co-chaperone FNIP1. Graphical Abstract Highlights • Casein-kinase-2-mediated sequential phosphorylation of the co-chaperone FNIP1 • FNIP1 relay phosphorylation leads to gradual activation of Hsp90 clients • Serine/threonine protein phosphatase 5 (PP5) dephosphorylates FNIP1 • O -GlcNAcylation causes ubiquitination and proteasomal degradation of FNIP1 Sager et al. show that casein-kinase-2-mediated sequential phosphorylation of the co-chaperone FNIP1 leads to incremental inhibition of Hsp90 ATPase activity and gradual activation of both kinase and non-kinase clients. O -GlcNAcylation antagonizes phosphorylation of FNIP1, preventing its interaction with Hsp90, and consequently promotes FNIP1 ubiquitination and proteasomal degradation. [ABSTRACT FROM AUTHOR]