Genotypic cluster analysis of Neisseria gonorrhoeae reveals a spectrum of sexual mixing including among HIV-serodiscordant men who have sex with men.

BACKGROUND: Men who have sex with men (MSM) are more vulnerable to acquiring sexually transmitted infections (STIs). In 2019, for instance, 74% of European Neisseria gonorrhoeae (Ng) cases among males affected MSM. A recent report by the World Health Organization showed that most of the 2020' interim targets to end STIs by 2030 had not been met. A broadened understanding of STI transmission networks could guide future elimination strategies and reduce the STI burden. Therefore, we used whole-genome sequencing (WGS) to determine Ng-clusters and assess sexual mixing. METHODS: WGS was performed on Ng-isolates collected at the Medical University of Vienna, Austria and was used for core genome multi-locus sequencing typing cluster analysis. Epidemiologic and infection-specific details were extracted from medical records. RESULTS: Genomic analysis and demographic data were available for 415 isolates, and 43.9% (182/415) were allocated to 31 Ng-clusters. Nine clusters comprised samples from heterosexual individuals only (women N = 4, human immunodeficiency virus (HIV)-negative men N = 49, HIV-positive man N = 1), nine clusters included MSM only (HIV-negative N = 22, HIV-positive N = 13) and 13 clusters included both heterosexuals and MSM (HIV-negative N = 75, HIV-positive N = 18). Current use of HIV pre-exposure prophylaxis (PrEP) was reported by 22.8% of MSM. In multivariate analysis, only 'MSM' predicted clustering with isolates from HIV-positive individuals (adjusted odds ratio 10.24 (95% CI 5.02-20.90)). CONCLUSIONS: Sexual mixing of HIV-positive, HIV-negative MSM and non-MSM was frequently observed. Furthermore, HIV-serodiscordant clustering highlights the importance of PrEP rollout to avert HIV transmission. Our findings can inform future STI prevention strategies and continuous surveillance efforts are required to keep up with transmission dynamics.

Scars are frequently found as late sequelae in individuals affected by the 2022 mpox outbreak.

BACKGROUND: The 2022 mpox outbreak continues, and while progress has been made in prevention strategies and potential treatment options, data on late sequelae following mpox are scarce. OBJECTIVE: This analysis aimed to assess the incidence of scar formation in individuals affected by the 2022 mpox outbreak. METHODS: All individuals diagnosed with mpox at the Department of Dermatology at the Medical University of Vienna in 2022 were included in this analysis. Follow-up data were collected throughout November 2023. 'Scar formation' was defined as having at least one scar at the former active mpox lesions. RESULTS: At our clinic, 28 cases of mpox presented between June 2022 and October 2022 and exclusively occurred in men who have sex with men (100%, 28/28), of whom 46% (13/28) were living with HIV, and 32% (9/28) were using pre-exposure prophylaxis (PrEP). Secondary bacterial infection of mpox lesions was suspected in six individuals, and all received systemic antibiotics. Overall, 26 were followed up in November 2023 after a median time of 15 months, and scar formations were found in 43% of cases. CONCLUSIONS: Our data provide insights into the late yet cumulating disease burden caused by the 2022 mpox outbreak. Highly effective prevention strategies are warranted to overcome the mpox epidemic and its potential late sequelae.

Rab30 facilitates lipid homeostasis during fasting.

To facilitate inter-tissue communication and the exchange of proteins, lipoproteins, and metabolites with the circulation, hepatocytes have an intricate and efficient intracellular trafficking system regulated by small Rab GTPases. Here, we show that Rab30 is induced in the mouse liver by fasting, which is amplified in liver-specific carnitine palmitoyltransferase 2 knockout mice (Cpt2L-/-) lacking the ability to oxidize fatty acids, in a Pparα-dependent manner. Live-cell super-resolution imaging and in vivo proximity labeling demonstrates that Rab30-marked vesicles are highly dynamic and interact with proteins throughout the secretory pathway. Rab30 whole-body, liver-specific, and Rab30; Cpt2 liver-specific double knockout (DKO) mice are viable with intact Golgi ultrastructure, although Rab30 deficiency in DKO mice suppresses the serum dyslipidemia observed in Cpt2L-/- mice. Corresponding with decreased serum triglyceride and cholesterol levels, DKO mice exhibit decreased circulating but not hepatic ApoA4 protein, indicative of a trafficking defect. Together, these data suggest a role for Rab30 in the selective sorting of lipoproteins to influence hepatocyte and circulating triglyceride levels, particularly during times of excessive lipid burden.

High cure rates of Mycoplasma genitalium following empiric treatment with azithromycin alongside frequent detection of macrolide resistance in Austria.

BACKGROUND: Mycoplasma genitalium (MG) is an emerging sexually transmitted infection, often harboring resistance-associated mutations to azithromycin (AZM). Global surveillance has been mandated to tackle the burden caused by MG, yet no data are available for Austria. Thus, we aimed to investigate the prevalence of MG, disease characteristics, and treatment outcomes at the largest Austrian HIV-and STI clinic. METHODS: All MG test results at the Medical University of Vienna from 02/2019 to 03/2022 were evaluated. Azithromycin resistance testing was implemented in 03/2021. RESULTS: Among 2671 MG tests, 199 distinct and mostly asymptomatic (68%; 135/199) MG infections were identified, affecting 10% (178/1775) of all individuals. This study included 83% (1479/1775) men, 53% (940/1775) men who have sex with men (MSM), 31% (540/1754) HIV+, and 15% (267/1775) who were using HIV pre-exposure prophylaxis (PrEP). In logistic regression analysis, 'MSM' (aOR 2.55 (95% CI 1.65-3.92)), 'use of PrEP' (aOR 2.29 (95% CI 1.58-3.32)), and 'history of syphilis' (aOR 1.57 (95% CI 1.01-2.24) were independent predictors for MG infections. Eighty-nine percent (178/199) received treatment: 11% (21/178) doxycycline (2 weeks), 52% (92/178) AZM (5 days), and 37% ( 65/178) moxifloxacin (7-10 days) and 60% (106/178) had follow-up data available showing negative tests in 63% (5/8), 76% (44/58) and 85% (34/40), respectively. AZM resistance analysis was available for 57% (114/199)) and detected in 68% (78/114). Resistance-guided therapy achieved a cure in 87% (53/61), yet, empiric AZM-treatment (prior to 03/2021) cleared 68% (26/38). CONCLUSIONS: Mycoplasma genitalium was readily detected in this Austrian observational study, affected predominantly MSM and often presented as asymptomatic disease. We observed a worryingly high prevalence of AZM resistance mutations; however, empiric AZM treatment cleared twice as many MG infections as expected.

Legionella pneumophila usurps host cell lipids for vacuole expansion and bacterial growth.

Vacuolar pathogens reside in membrane-bound compartments within host cells. Maintaining the integrity of this compartment is paramount to bacterial survival and replication as it protects against certain host surveillance mechanisms that function to eradicate invading pathogens. Preserving this compartment during bacterial replication requires expansion of the vacuole membrane to accommodate the increasing number of bacteria, and yet, how this is accomplished remains largely unknown. Here, we show that the vacuolar pathogen Legionella pneumophila exploits multiple sources of host cell fatty acids, including inducing host cell fatty acid scavenging pathways, in order to promote expansion of the replication vacuole and bacteria growth. Conversely, when exogenous lipids are limited, the decrease in host lipid availability restricts expansion of the replication vacuole membrane, resulting in a higher density of bacteria within the vacuole. Modifying the architecture of the vacuole prioritizes bacterial growth by allowing the greatest number of bacteria to remain protected by the vacuole membrane despite limited resources for its expansion. However, this trade-off is not without risk, as it can lead to vacuole destabilization, which is detrimental to the pathogen. However, when host lipid resources become extremely scarce, for example by inhibiting host lipid scavenging, de novo biosynthetic pathways, and/or diverting host fatty acids to storage compartments, bacterial replication becomes severely impaired, indicating that host cell fatty acid availability also directly regulates L. pneumophila growth. Collectively, these data demonstrate dual roles for host cell fatty acids in replication vacuole expansion and bacterial proliferation, revealing the central functions for these molecules and their metabolic pathways in L. pneumophila pathogenesis.

Asymptomatic lymphogranuloma venereum is commonly found among men who have sex with men in Austria.

BACKGROUND AND OBJECTIVES: Serovar L1-L3 of Chlamydia trachomatis (CT) causes lymphogranuloma venereum (LGV). A surge in LGV-cases has been observed among HIV-positive men who have sex with men (MSM). Discrimination between LGV and non-LGV is pivotal since it has major treatment implications. Here, we aimed to determine the prevalence and characteristics of LGV among CT-infections. PATIENTS AND METHODS: All CT-positive results from 04/2014-12/2021 at the four largest Austrian HIV and STI clinics were evaluated. Disease characteristics and patient demographics were analyzed. RESULTS: Overall, n  =  2,083 infections of CT were documented in n  =  1,479 individual patients: median age was 31.4 years, 81% were male, 59% MSM, 44% HIV-positive, 13% on HIV pre-exposure-prophylaxis. Available serovar analyses (61% [1,258/2,083]) showed L1-L3 in 15% (192/1,258). Considering only MSM with rectal CT-infection, LGV accounted for 23% (101/439). Cases of LGV vs. other CT-infections were primarily MSM (92% [177/192] vs. 62% [1,179/1,891], p < 0.001), more often HIV-positive (64% [116/180] vs. 46% [631/1,376]; p < 0.001) and had frequently concomitant syphilis infection (18% [32/180] vs. 7% [52/749]; p < 0.001). LGV commonly manifested as proctitis (38% [72/192]) whereas 45% (87/192) were asymptomatic. CONCLUSIONS: Lymphogranuloma venereum accounted for 23% of rectal CT-infections in MSM. Furthermore, 45% of all LGV-cases were asymptomatic. In the absence of CT-serovar analysis, a high LGV prevalence should be considered in risk-populations and guide empiric treatment selection.

Sexually Transmitted Dermatophytes Can Cause Severe Infection Among Men who Have Sex With Men as Tinea Genitalis.

Very limited data on tinea genitalis, a potentially severe dermatophytosis transmitted during sexual intercourse affecting the genital area, suggest its potential to cause outbreaks. Thus, we investigated genital dermatophyte infections at an HIV/sexually transmitted infection clinic and identified 17 men who have sex with men (all people with HIV or pre-exposure prophylaxis users) diagnosed with tinea genitalis.

Pan-tumor survey of ROS1 fusions detected by next-generation RNA and whole transcriptome sequencing.

BACKGROUND: Two ROS1 tyrosine kinase inhibitors have been approved for ROS1 fusion positive (ROS1+) non-small cell lung cancer (NSCLC) tumors. We performed a pan-tumor analysis of the incidence of ROS1 fusions to assess if more ROS1+ patients who could benefit from ROS1 TKIs could be identified. METHODS: A retrospective analysis of ROS1 positive solid malignancies identified by targeted RNA sequencing and whole transcriptome sequencing of clinical tumor samples performed at Caris Life Science (Phoenix, AZ). RESULTS: A total of 259 ROS1+ solid malignancies were identified from approximately 175,350 tumors that underwent next-generation sequencing (12% from targeted RNA sequencing [Archer]; 88% from whole transcriptome sequencing). ROS1+ NSCLC constituted 78.8% of the ROS1+ solid malignancies, follow by glioblastoma (GBM) (6.9%), and breast cancer (2.7%). The frequency of ROS1 fusion was approximately 0.47% among NSCLC, 0.29% for GBM, 0.04% of breast cancer. The mean tumor mutation burden for all ROS1+ tumors was 4.8 mutations/megabase. The distribution of PD-L1 (22C3) expression among all ROS1+ malignancies were 0% (18.6%), 1%-49% (29.4%), and ≥ 50% (60.3%) [for NSCLC: 0% (17.8%); 1-49% (27.7%); ≥ 50% (53.9%). The most common genetic co-alterations of ROS1+ NSCLC were TP53 (29.1%), SETD2 (7.3%), ARIAD1A (6.3%), and U2AF1 (5.6%). CONCLUSIONS: ROS1+ NSCLC tumors constituted the majority of ROS1+ solid malignancies with four major fusion partners. Given that > 20% of ROS1+ solid tumors may benefit from ROS1 TKIs treatment, comprehensive genomic profiling should be performed on all solid tumors.

Proteomics identifies the developmental regulation of HKDC1 in liver of pigs and mice.

During the perinatal period, unique metabolic adaptations support energetic requirements for rapid growth. To gain insight into perinatal adaptations, quantitative proteomics was performed comparing the livers of Yorkshire pigs at postnatal day 7 and adult. These data revealed differences in the metabolic control of liver function including significant changes in lipid and carbohydrate metabolic pathways. Newborn livers showed an enrichment of proteins in lipid catabolism and gluconeogenesis concomitant with elevated liver carnitine and acylcarnitines levels. Sugar kinases were some of the most dramatically differentially enriched proteins compared with neonatal and adult pigs including galactokinase 1 (Galk1), ketohexokinase (KHK), hexokinase 1 (HK1), and hexokinase 4 (GCK). Interestingly, hexokinase domain containing 1 (HKDC1), a newly identified fifth hexokinase associated with glucose disturbances in pregnant women, was highly enriched in the liver during the prenatal and perinatal periods and continuously declined throughout postnatal development in pigs and mice. These changes were confirmed via Western blot and mRNA expression. These data provide new insights into the developmental and metabolic adaptations in the liver during the transition from the perinatal period to adulthood in multiple mammalian species.

Peroxisome proliferator activated receptor-γ in osteoblasts controls bone formation and fat mass by regulating sclerostin expression.

The nuclear receptor peroxisome proliferator activated receptor-γ (PPARγ) is a key contributor to metabolic function via its adipogenic and insulin-sensitizing functions, but it has negative effects on skeletal homeostasis. Here, we questioned whether the skeletal and metabolic actions of PPARγ are linked. Ablating Pparg expression in osteoblasts and osteocytes produced a high bone mass phenotype, secondary to increased osteoblast activity, and a reduction in subcutaneous fat mass because of reduced fatty acid synthesis and increased fat oxidation. The skeletal and metabolic phenotypes in Pparg mutants proceed from the regulation of sclerostin production by PPARγ. Mutants exhibited reductions in skeletal Sost expression and serum sclerostin levels while increasing production normalized both phenotypes. Importantly, disrupting the production of sclerostin synergized with the insulin-sensitizing actions of a PPARγ agonist while preventing bone loss. These data suggest that modulating sclerostin action may prevent bone loss associated with anti-diabetic therapies and augment their metabolic actions.

Pan-tumor survey of RET fusions as detected by next-generation RNA sequencing identified RET fusion positive colorectal carcinoma as a unique molecular subset.

BACKGROUND: RET fusions are driver alterations in cancer and are most commonly found in non-small cell lung cancer and well-differentiated thyroid cancer. However, RET fusion have been reported in other solid tumors. MATERIAL AND METHODS: A retrospective analysis of RET+ solid malignancies identified by targeted RNA sequencing and whole transcriptome sequencing of clinical tumor samples performed at Caris Life Science (Phoenix, AZ). RESULTS: As of March 22, 2022, a total of 378 RET+ solid malignancies were identified in 15 different tumor types and carcinoma of unknown primary (CUP) that underwent next-generation RNA sequencing. RET+ NSCLC and RET+ thyroid cancer constituted 66.9% and 11.1% of the RET+ solid malignancies, respectively. RET+ colorectal adenocarcinoma and RET+ breast adenocarcinoma constituted 10.1% and 2.6%, respectively. The estimated frequency of RET fusions within specific tumor types were NSCLC 0.7%, thyroid cancer 3.1%, colorectal cancer 0.2% and breast cancer 0.1%. KIF5B (46.8%) was the most common fusion partner followed by CCDC6 (28.3%) and NCOA4 (13.8%) in RET+ solid tumors. KIF5B-RET was the dominant fusion variant in RET+ NSCLC, NCOA4-RET was the dominant variant in RET+ colorectal carcinoma, and CCDC6-RET was the dominant variant in thyroid cancer. The most common single gene alterations in RET+ tumors were TP53 (34.8%), RASA1 (14.3%) and ARIAD1A (11.6%). RET+ CRC had a high median TMB of 20.0 and were commonly MSI-H. CONCLUSIONS: RET fusions were identified in multiple tumor types. With a higher median TMB and commonly MSI-H, RET fusion positive CRC may be a unique molecular subset of CRC.

Myocardial Perfusion SPECT and ATTR imaging 2021 in Germany: Results of the 9th Survey.

AIM: This paper presents the results of the 9th survey of myocardial perfusion SPECT (MPS) from the reporting year 2021. METHODS: 218 questionnaires (131 practices (PR), 58 hospitals (HO), 29 university hospitals (UH)) were evaluated. Results of the last survey 2018 are set in squared brackets. RESULTS: MPS data from a total of 133,057 [145,930] patients (-8.8%) with 131,868 [143,707] stress and 106,546 [121,899] rest MPS were analysed. A comparison with official data revealed that 54% all MPS were recorded. From 2018 to 2021, official data showed a every year an increase in MPS numbers. On average, 610 [502] MPS patients (+22%) were examined in each department. 74% [69%] of the responders reported an increase or no changes in their MPS patient numbers. Ambulatory care cardiologists represented as always, the mayor referral group (68% [69%]). For the first time, pharmacological stress was more frequently applied than ergometry (42% [51]). Regadenoson was mostly used. The use of the different protocols remained nearly unchanged. Two-day protocols were predominantly applied (49% [48%]). A shift from multi-headed cameras (58% [72%]) to SPECT-CT systems (24% [17%]) was found. Attenuation correction was performed in 33% [26%] of all MPS. 88% [86%] of all stress, 88% [87%] of all rest and 87% [83%] of all stress and rest MPS were acquired as gated SPECT. 72% [67%] of all departments performed scoring by default. The number of departments without scoring decreased to 13% [16%]. CONCLUSIONS: The MPS Study 2021 shows that the long-term positive development of MPS imaging in Germany is continuing. The COVID-19 pandemia did not change this trend. The procedural and technical details of MPS imaging reveal a high level of guideline conformity.

ERBB family fusions are recurrent and actionable oncogenic targets across cancer types.

Purpose: Gene fusions involving receptor tyrosine kinases (RTKs) define an important class of genomic alterations with many successful targeted therapies now approved for ALK, ROS1, RET and NTRK gene fusions. Fusions involving the ERBB family of RTKs have been sporadically reported, but their frequency has not yet been comprehensively analyzed and functional characterization is lacking on many types of ERBB fusions. Materials and methods: We analyzed tumor samples submitted to Caris Life Sciences (n=64,354), as well as the TCGA (n=10,967), MSK IMPACT (n=10,945) and AACR GENIE (n=96,324) databases for evidence of EGFR, ERBB2 and ERBB4 gene fusions. We also expressed several novel fusions in cancer cell lines and analyzed their response to EGFR and HER2 tyrosine kinase inhibitors (TKIs). Results: In total, we identified 1,251 ERBB family fusions, representing an incidence of approximately 0.7% across all cancer types. EGFR, ERBB2, and ERBB4 fusions were most frequently found in glioblastoma, breast cancer and ovarian cancer, respectively. We modeled two novel types of EGFR and ERBB2 fusions, one with a tethered kinase domain and the other with a tethered adapter protein. Specifically, we expressed EGFR-ERBB4, EGFR-SHC1, ERBB2-GRB7 and ERBB2-SHC1, in cancer cell lines and demonstrated that they are oncogenic, regulate downstream signaling and are sensitive to small molecule inhibition with EGFR and HER2 TKIs. Conclusions: We found that ERBB fusions are recurrent mutations that occur across multiple cancer types. We also establish that adapter-tethered and kinase-tethered fusions are oncogenic and can be inhibited with EGFR or HER2 inhibitors. We further propose a nomenclature system to categorize these fusions into several functional classes.

Mitochondrial pyruvate metabolism and glutaminolysis toggle steady-state and emergency myelopoiesis.

To define the metabolic requirements of hematopoiesis, we examined blood lineages in mice conditionally deficient in genes required for long-chain fatty acid oxidation (Cpt2), glutaminolysis (Gls), or mitochondrial pyruvate import (Mpc2). Genetic ablation of Cpt2 or Gls minimally impacted most blood lineages. In contrast, deletion of Mpc2 led to a sharp decline in mature myeloid cells and a slower reduction in T cells, whereas other hematopoietic lineages were unaffected. Yet MPC2-deficient monocytes and neutrophils rapidly recovered due to a transient and specific increase in myeloid progenitor proliferation. Competitive bone marrow chimera and stable isotope tracing experiments demonstrated that this proliferative burst was progenitor intrinsic and accompanied by a metabolic switch to glutaminolysis. Myeloid recovery after loss of MPC2 or cyclophosphamide treatment was delayed in the absence of GLS. Reciprocally, MPC2 was not required for myeloid recovery after cyclophosphamide treatment. Thus, mitochondrial pyruvate metabolism maintains myelopoiesis under steady-state conditions, while glutaminolysis in progenitors promotes emergency myelopoiesis.

Mitochondrial ß-oxidation of adipose-derived fatty acids by osteoblasts fuels parathyroid hormone-induced bone formation.

The energetic costs of bone formation require osteoblasts to coordinate their activities with tissues, like adipose, that can supply energy-dense macronutrients. In the case of intermittent parathyroid hormone (PTH) treatment, a strategy used to reduce fracture risk, bone formation is preceded by a change in systemic lipid homeostasis. To investigate the requirement for fatty acid oxidation by osteoblasts during PTH-induced bone formation, we subjected mice with osteoblast-specific deficiency of mitochondrial long-chain ß-oxidation as well as mice with adipocyte-specific deficiency for the PTH receptor or adipose triglyceride lipase to an anabolic treatment regimen. PTH increased the release of fatty acids from adipocytes and ß-oxidation by osteoblasts, while the genetic mouse models were resistant to the hormone's anabolic effect. Collectively, these data suggest that PTH's anabolic actions require coordinated signaling between bone and adipose, wherein a lipolytic response liberates fatty acids that are oxidized by osteoblasts to fuel bone formation.

Impact of a telemonitoring intervention in patients with chronic heart failure in Germany: A difference-in-difference matching approach using real-world data.

INTRODUCTION: The aim of this study was to evaluate the effects of a non-invasive telemonitoring intervention on mortality, healthcare costs, and hospital and pharmaceutical utilisation in patients with chronic heart failure (CHF) of a large statutory health insurer in Germany. METHODS: In a retrospective observational cohort study using real-world data, we assessed differences between 635 patients who received a telemonitoring intervention versus 635 receiving usual care covering 36 months after intervention. We used propensity score matching on a set of 102 parameters collected in the 24-month pre-intervention period to correct for observed differences, as well as difference-in-difference (DiD) estimators to account for unobserved differences. We analysed the effect of the intervention for up to three years on (i) all-cause mortality; (ii) costs (i.e. inpatient stays, ambulatory care, pharmaceuticals, and medical aids and appliances); and (iii) healthcare utilisation (i.e. length and number of hospital stays, number of prescriptions). RESULTS: DiD estimates suggest lower inpatient costs of the telemonitoring group of up to €1160 (95% confidence interval (CI): -2253 to -69) in year three. Ambulatory care costs increased significantly in all three years up to €316 (95% CI: 1267 to 505) per year. Telemonitoring had a positive effect on survival (hazard ratio = 0.71; 95% CI: 0.51 to 0.99) and increased the number of prescriptions for diuretics. Effects were more prominent for patients with severe CHF. DISCUSSION: The study suggests that the telemonitoring intervention led to a significant decrease in mortality and a shift in costs from the inpatient to the ambulatory care sector 36 months after intervention.

Requirement of hepatic pyruvate carboxylase during fasting, high fat, and ketogenic diet.

Pyruvate has two major fates upon entry into mitochondria, the oxidative decarboxylation to acetyl-CoA via the pyruvate decarboxylase complex or the biotin-dependent carboxylation to oxaloacetate via pyruvate carboxylase (Pcx). Here, we have generated mice with a liver-specific KO of pyruvate carboxylase (PcxL-/-) to understand the role of Pcx in hepatic mitochondrial metabolism under disparate physiological states. PcxL-/- mice exhibited a deficit in hepatic gluconeogenesis and enhanced ketogenesis as expected but were able to maintain systemic euglycemia following a 24 h fast. Feeding a high-fat diet to PcxL-/- mice resulted in animals that were resistant to glucose intolerance without affecting body weight. However, we found that PcxL-/- mice fed a ketogenic diet for 1 week became severely hypoglycemic, demonstrating a requirement for hepatic Pcx for long-term glycemia under carbohydrate-limited diets. Additionally, we determined that loss of Pcx was associated with an induction in the abundance of lysine-acetylated proteins in PcxL-/- mice regardless of physiologic state. Furthermore, liver acetyl-proteomics revealed a biased induction in mitochondrial lysine-acetylated proteins. These data show that Pcx is important for maintaining the proper balance of pyruvate metabolism between oxidative and anaplerotic pathways.

Mitochondrial fatty acid ß-oxidation is important for normal osteoclast formation in growing female mice.

Skeletal remodeling is an energy demanding process that is linked to nutrient availability and the levels of metabolic hormones. While recent studies have examined the metabolic requirements of bone formation by osteoblasts, much less is known about the energetic requirements of bone resorption by osteoclasts. The abundance of mitochondria in mature osteoclasts suggests that the production of an acidified micro-environment conducive to the ionization of hydroxyapatite, secretion of matrix-degrading enzymes, and motility during resorption requires significant energetic capacity. To investigate the contribution of mitochondrial long chain fatty acid ß-oxidation to osteoclast development, we disrupted the expression of carnitine palmitoyltransferase-2 (Cpt2) in myeloid-lineage cells. Fatty acid oxidation increases dramatically in bone marrow cultures stimulated with RANKL and M-CSF and microCT analysis revealed that the genetic inhibition of long chain fatty acid oxidation in osteoclasts significantly increases trabecular bone volume in female mice secondary to reduced osteoclast numbers. In line with these data, osteoclast precursors isolated from Cpt2 mutants exhibit reduced capacity to form large-multinucleated osteoclasts, which was not rescued by exogenous glucose or pyruvate, and signs of an energetic stress response. Together, our data demonstrate that mitochondrial long chain fatty acid oxidation by the osteoclast is required for normal bone resorption as its inhibition produces an intrinsic defect in osteoclast formation.

Genomic and Molecular Profiling of Human Papillomavirus Associated Head and Neck Squamous Cell Carcinoma Treated with Immune Checkpoint Blockade Compared to Survival Outcomes.

Recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) patients overall have a poor prognosis. However, human papillomavirus (HPV)-associated R/M oropharyngeal squamous cell carcinoma (OPSCC) is associated with a better prognosis compared to HPV-negative disease. Immune checkpoint blockade (ICB) is the standard of care for R/M HNSCC. However, whether HPV and its surrogate marker, p16, portend an improved response to ICB remains controversial. We queried the Caris Life Sciences CODEai database for p16+ and p16- HNSCC patients using p16 as a surrogate for HPV. A total of 2905 HNSCC (OPSCC, n = 948) cases were identified. Of those tested for both HPV directly and p16, 32% (251/791) were p16+ and 28% (91/326) were HPV+. The most common mutation in the OPSCC cohort was TP53 (33%), followed by PIK3CA (17%) and KMT2D (10.6%). TP53 mutations were more common in p16- (49%) versus the p16+ group (10%, p < 0.0005). Real-world overall survival (rwOS) was longer in p16+ compared to p16- OPSCC patients, 33.3 vs. 19.1 months (HR = 0.597, p = 0.001), as well as non-oropharyngeal (non-OP) HNSCC patients (34 vs. 17 months, HR 0.551, p = 0.0001). There was no difference in the time on treatment (TOT) (4.2 vs. 2.8 months, HR 0.796, p = 0.221) in ICB-treated p16+ vs. p16- OPSCC groups. However, p16+ non-OP HNSCC patients treated with ICB had higher TOT compared to the p16- group (4.3 vs. 3.3 months, HR 0.632, p = 0.016), suggesting that p16 may be used as a prognostic biomarker in non-OP HNSCC, and further investigation through prospective clinical trials is warranted.