Investigating potent cardioprotective compounds as ACE inhibitors in Saraca asoca.

Saraca asoca is a traditional medicinal plant whose all plant parts are exceptionally effective in terms of antimicrobial, anti-inflammatory, antioxidant, anti-carcinogenic, free radical scavenging,anti-arthritic, and hypolipidemic properties. As cardio-vascular problems occur for many reasons, antioxidants with free radical scavenging properties of plants and herbs are highly effective in treating cardio-related disorders. Though Saraca asoca has been preferred as a tonic and medicinal supplement for women's health, because of the huge variety of bioactive compounds, Saraca asoca needs to be explored for its cardio-protective properties. This review aims to summarize the in vivo and in vitro studies done on Saraca asoca along with the exploration of bioactive compounds in various parts of the plant which will display its cardio-protective potential with its rich bioactive compounds as ACE inhibitors. All relevant information on Saraca asoca in treating and preventing cardio-related disorders has been collected from electronic databases including PubMed, Google Scholar, Web of Science, and Science Direct. Various parts of Saraca asoca were studied to assess its pharmacological and cardioprotective properties. The bioactive compounds of Saraca asoca have been assessed to explore its role as anti-hypertensive, antioxidant, ACE inhibitors, and cardio-protective with the help of in-vivo, in-vitro studies and other research studies. This thorough review focuses on the potent natural bioactive compounds in various parts of Saraca asoca exhibiting its potential as a cardioprotective agent while incorporating historical, chemical, and therapeutic views.

Pleural Metastatic Melanoma With Recurrent Malignant Pleural Effusions.

Pleural metastatic melanoma is rare, and associated malignant pleural effusions are even rarer. We present a case of pleural metastatic melanoma with recurrent malignant pleural effusions. The initial diagnosis showed no metastatic disease, and the patient underwent resection and received a year of immunotherapy for localized disease. However, two years later, the patient presented with pleural metastatic melanoma with unresolving malignant pleural effusions requiring an indwelling pleural catheter and eventually, thoracotomy with decortication. Clinicians should have a high index of suspicion for pleural metastatic melanoma in the setting of recurrent pleural effusions, even though it is a rare occurrence.

Catastrophic Antiphospholipid Syndrome: A Life-Threatening Condition.

Antiphospholipid syndrome (APS) is characterized by thrombosis in any organ or tissue, accompanied by the presence of antiphospholipid antibodies. Although rare, APS can progress to catastrophic APS (CAPS), a life-threatening complication involving the development of multi-organ thromboses. The mortality rate is high. Treatment consists of triple therapy with anticoagulation, glucocorticoids, and therapeutic plasmapheresis or intravenous immunoglobulins. We present a case of a patient with CAPS, requiring a multidisciplinary team approach to help diagnose and treat this complex disease.

Ruptured Hepatocellular Carcinoma: A Case Report.

Hepatocellular carcinoma (HCC) is one of the most common primary liver tumors in the world. In the United States, it is very uncommon for the liver mass to spontaneously rupture, especially if it has already been treated with embolization. Prompt diagnosis and treatment are necessary to improve the overall prognosis. Unfortunately, even with treatment, the patient can still rapidly decline. We present a case of a patient who was diagnosed with HCC and received treatment with transarterial radioembolization (TARE) with yttrium-90 (Y90). Despite this, the patient's liver mass grew and spontaneously ruptured. Although the patient received additional embolizations for his mass, he still deteriorated and eventually expired.

A comprehensive review on nutritional interventions and nutritive elements: Strengthening immunity for effective defense mechanism during pandemic.

The pandemic has brought attention to the importance of a healthy immune system in preventing infectious diseases. In this in-depth review, the process by which nutritional interventions and fundamental nutrients affect immune function has been discussed with the goal of enhancing the body's natural defenses against viral infections. We explored the complex interplay between diet and immunology, highlighting the essential nutrients, vitamins, minerals, and bioactive substances that are crucial for enhancing immune response. We also investigated the effect of dietary patterns and supplementation methods on immune function. We assessed the effectiveness and potential mechanisms of action of various nutritional therapies in modifying immune responses through a thorough examination of scientific literature. Additionally, we go through the significance of individualized nutrition and highlight possible factors to consider for vulnerable groups, such as the elderly and people with chronic conditions. This review attempts to provide a thorough understanding of the role of diet in boosting immunity by synthesizing available research. It also offers insights into practical methods for enhancing the immune function during the current epidemic and in the future.

Sirenomelia in Twin Pregnancy: A Case Report.

Sirenomelia is a rare congenital disorder that was once thought to be a severe case of caudal regression but is now thought to be entirely separate. It is often referred to as the "mermaid syndrome" because it causes the lower limbs to atrophy to varying degrees, giving the impression of a mermaid's tail or fin. The syndrome is often viewed as fatal due to the accompanying visceral deformities. Our case was a live born, delivered at term by caesarean section, to a 30-year-old third gravida having twin pregnancy. Examination of the baby revealed caudal dysgenesis with fusion of lower limbs, non-identifiable external genitalia and anus. The infant survived for 11 hours after birth. We report this case due to their rarity and term live birth. While sirenomelia is uncommon, the absence of distinct lower limbs on ultrasonography in the presence of oligo or anhydramnios may prompt consideration of the diagnosis of sirenomelia.

Immune Thrombocytopenia following COVID-19 Vaccine.

Several vaccines have been developed and are being administered against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Common side effects include fever, chills, headache, myalgia, and soreness at the injection site. However, some rare adverse effects have also been reported. We present a case of induced thrombocytopenia presenting with petechiae and mucosal bleeding which developed as an adverse response after first-dose administration of the Moderna COVID-19 vaccine.

68Ga-NODAGA-Exendin-4 PET/CT Improves the Detection of Focal Congenital Hyperinsulinism.

Surgery with curative intent can be offered to congenital hyperinsulinism (CHI) patients, provided that the lesion is focal. Radiolabeled exendin-4 specifically binds the glucagonlike peptide 1 receptor on pancreatic ß-cells. In this study, we compared the performance of 18F-DOPA PET/CT, the current standard imaging method for CHI, and PET/CT with the new tracer 68Ga-NODAGA-exendin-4 in the preoperative detection of focal CHI. Methods: Nineteen CHI patients underwent both 18F-DOPA PET/CT and 68Ga-NODAGA-exendin-4 PET/CT before surgery. The images were evaluated in 3 settings: a standard clinical reading, a masked expert reading, and a joint reading. The target (lesion)-to-nontarget (normal pancreas) ratio was determined using SUVmax Image quality was rated by pediatric surgeons in a questionnaire. Results: Fourteen of 19 patients having focal lesions underwent surgery. On the basis of clinical readings, the sensitivity of 68Ga-NODAGA-exendin-4 PET/CT (100%; 95% CI, 77%-100%) was higher than that of 18F-DOPA PET/CT (71%; 95% CI, 42%-92%). Interobserver agreement between readings was higher for 68Ga-NODAGA-exendin-4 than for 18F-DOPA PET/CT (Fleiss κ = 0.91 vs. 0.56). 68Ga-NODAGA-exendin-4 PET/CT provided significantly (P = 0.021) higher target-to-nontarget ratios (2.02 ± 0.65) than did 18F-DOPA PET/CT (1.40 ± 0.40). On a 5-point scale, pediatric surgeons rated 68Ga-NODAGA-exendin-4 PET/CT as superior to 18F-DOPA PET/CT. Conclusion: For the detection of focal CHI, 68Ga-NODAGA-exendin-4 PET/CT has higher clinical sensitivity and better interobserver correlation than 18F-DOPA PET/CT. Better contrast and image quality make 68Ga-NODAGA-exendin-4 PET/CT superior to 18F-DOPA PET/CT in surgeons' intraoperative quest for lesion localization.

The Development of Cognate Awareness in Child Second/Third Language Learners of French in French Immersion: The Effects of Orthographic Overlap and Cognate Status.

Purpose Our 1-year longitudinal study tracked the development of cognate awareness among second (L2) and third language (L3) learners of French in French immersion in Grades 1 and 2 to explore the impact of orthographic overlap and cognate status (true vs. false) on children's ability to recognize cognate relationships. We also assessed the impact of French L2/L3 status on performance. Method We compared performance on three conditions (true cognates with same and similar spellings, false cognates with same spellings) within and across grades. We used a direct measure of cognate awareness that required children (n = 81) to distinguish true from false cognates presented orally and in print. Results Overall, Grade 1 children failed to recognize cognate relationships between true cognates with similar spellings, but successfully recognized true cognates with same spellings. Performance on all conditions increased significantly between Grades 1 and 2. The greatest improvement was seen on true cognates with similar spellings. Performance on false cognates was inferior to performance on true cognates with same spellings in Grade 1, and inferior to performance on both same and similar spelled true cognates in Grade 2. No differences were found due to L2/L3 status. Conclusions Among sequential learners of L2/L3 French in the early stages of additional language learning, cognate awareness is impacted by the degree of orthographic overlap, as well as by cognate status. Children's ability to recognize cross-language orthographic and semantic relationships improves substantially across the early elementary grades. Supplemental Material https://doi.org/10.23641/asha.16821106.

Long-circulating XTEN864-annexin A5 fusion protein for phosphatidylserine-related therapeutic applications.

Annexin A5 (anxA5) is a marker for apoptosis, but has also therapeutic potential in cardiovascular diseases, cancer, and, due to apoptotic mimicry, against dangerous viruses, which is limited by the short blood circulation. An 864-amino-acid XTEN polypeptide was fused to anxA5. XTEN864-anxA5 was expressed in Escherichia coli and purified using XTEN as tag. XTEN864-anxA5 was coupled with DTPA and indium-111. After intravenous or subcutaneous injection of 111In-XTEN864-anxA5, mouse blood samples were collected for blood half-life determination and organ samples for biodistribution using a gamma counter. XTEN864-anxA5 was labeled with 6S-IDCC to confirm binding to apoptotic cells using flow cytometry. To demonstrate targeting of atherosclerotic plaques, XTEN864-anxA5 was labeled with MeCAT(Ho) and administered intravenously to atherosclerotic ApoE-/- mice. MeCAT(Ho)-XTEN864-anxA5 was detected together with MeCAT(Tm)-MAC-2 macrophage antibodies by imaging mass cytometry (CyTOF) of aortic root sections. The ability of anxA5 to bind apoptotic cells was not affected by XTEN864. The blood half-life of XTEN864-anxA5 was 13 h in mice after IV injection, markedly longer than the 7-min half-life of anxA5. 96 h after injection, highest amounts of XTEN864-anxA5 were found in liver, spleen, and kidney. XTEN864-anxA5 was found to target the adventitia adjacent to atherosclerotic plaques. XTEN864-anxA5 is a long-circulating fusion protein that can be efficiently produced in E. coli and potentially circulates in humans for several days, making it a promising therapeutic drug.

SPECT/CT Imaging, Biodistribution and Radiation Dosimetry of a 177Lu-DOTA-Integrin αvß6 Cystine Knot Peptide in a Pancreatic Cancer Xenograft Model.

INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignant neoplasms, as many cases go undetected until they reach an advanced stage. Integrin αvß6 is a cell surface receptor overexpressed in PDAC. Consequently, it may serve as a target for the development of probes for imaging diagnosis and radioligand therapy. Engineered cystine knottin peptides specific for integrin αvß6 have recently been developed showing high affinity and stability. This study aimed to evaluate an integrin αvß6-specific knottin molecular probe containing the therapeutic radionuclide 177Lu for targeting of PDAC. METHODS: The expression of integrin αvß6 in PDAC cell lines BxPC-3 and Capan-2 was analyzed using RT-qPCR and immunofluorescence. In vitro competition and saturation radioligand binding assays were performed to calculate the binding affinity of the DOTA-coupled tracer loaded with and without lutetium to BxPC-3 and Capan-2 cell lines as well as the maximum number of binding sites in these cell lines. To evaluate tracer accumulation in the tumor and organs, SPECT/CT, biodistribution and dosimetry projections were carried out using a Capan-2 xenograft tumor mouse model. RESULTS: RT-qPCR and immunofluorescence results showed high expression of integrin αvß6 in BxPC-3 and Capan-2 cells. A competition binding assay revealed high affinity of the tracer with IC50 values of 1.69 nM and 9.46 nM for BxPC-3 and Capan-2, respectively. SPECT/CT and biodistribution analysis of the conjugate 177Lu-DOTA-integrin αvß6 knottin demonstrated accumulation in Capan-2 xenograft tumors (3.13 ± 0.63%IA/g at day 1 post injection) with kidney uptake at 19.2 ± 2.5 %IA/g, declining much more rapidly than in tumors. CONCLUSION: 177Lu-DOTA-integrin αvß6 knottin was found to be a high-affinity tracer for PDAC tumors with considerable tumor accumulation and moderate, rapidly declining kidney uptake. These promising results warrant a preclinical treatment study to establish therapeutic efficacy.

In Comparison to PSA, Interim Ga-68-PSMA PET/CT Response Evaluation Based on Modified RECIST 1.1 After 2nd Cycle Is Better Predictor of Overall Survival of Prostate Cancer Patients Treated With 177Lu-PSMA.

BACKGROUND: Prostate-specific membrane antigen (PSMA) targeting radioligands have transformed treatment of prostate cancer. Radioligand therapy (RLT) with 177Lu-PSMA in metastasized castration resistant prostate cancer (mCRPC) achieves objective response and disease stabilization in roughly two third of patients, whereas one third of patients progress. This study was performed to assess the role of interim PSMA PET/CT after the 2nd cycle of RLT for early prediction of overall survival in patients undergoing RLT with 177Lu-PSMA. METHODS: 38 mCRPC patients (68.9 ± 8.1 y) treated with at least two cycles of RLT at 8 week intervals and interim 68Ga-PSMA PET/CT (PET) at 8-10 weeks after the 2nd cycle of RLT were included in this study. Prostate-specific antigen (PSA) response was evaluated according to the Prostate Cancer Working Group 3 criteria. Radiographic response assessment of soft tissue, lymph node, and bone lesions was performed according to RECIST 1.1 including the PET component. Patients' data were collected for follow-up from the local Comprehensive Cancer Center Register. RESULTS: Median follow-up was 19.7 months (4.7-45.3). PSA response after the 2nd therapy cycle showed partial remission (PR) in 23.7%, stable disease (SD) in 50%, and progressive disease (PD) in 26.3% of patients. In comparison, 52.6, 23.7, and 23.7% of patients showed PR, SD, and PD respectively on PET/CT. The strength of agreement between PSA response and PET/CT response criteria was only fair (kappa 0.346). Median overall survival (OS) was 22.5 months (95% CI: 15.8-29.2). Median OS stratified to PSA/PET response was 25.6/25.6 months for PR, 21.7/30.6 months for SD and 19.4/13.1 months for PD (p = 0.496 for PSA and 0.013 for PET/CT response). CONCLUSIONS: Interim PSMA PET/CT based response evaluation at 8-10 weeks after the 2nd cycle of RLT is predictive of overall survival and PD in patients treated with 177Lu-PSMA. On the contrary, PSA appears to have only limited predictive value.

Effect of Peptide Dose on Radiation Dosimetry for Peptide Receptor Radionuclide Therapy with 177Lu-DOTATOC: A Pilot Study.

BACKGROUND: Optimal peptide concentration in treatment with 177Lu-DOTATOC/DOTATATE is a matter of debate. Most of the studies with peptide receptor radionuclide therapy mention peptide dose ranging between 100 and 250 µg. The aim of this is to identify possible differences in radiation-absorbed doses (D/Gy) to tumor and kidney as a function of the peptide mass dose in order to identify the most suitable peptide dose for treatment. The therapeutic index (Dtumor/Dkidneys) was assessed as a key parameter for the treatment response. MATERIALS AND METHODS: Five patients with metastasized Grade 1 to Grade 2 neuroendocrine tumor were analyzed in this study. Patients (n = 4) received two cycles of treatment with intravenously injected 177Lu-DOTATOC containing peptide mass doses of 200 µg and 90 µg, alternatively; one patient was treated with 90 µg peptide mass in both the therapy cycles. Whole-body (head to mid-thigh) three-dimensional single-photon emission computerized tomography (3D SPECT)/CT images were acquired at 1, 4, 24, 48, and 72 h following the injection of 177Lu-DOTATOC. Attenuation correction for 3D SPECT images was performed using CT data acquired and fused with the SPECT data (SPECT/CT). RESULTS: Overall, 28 target lesions (liver n = 17, lung n = 4, lymph nodes n = 1, and bone n = 2) were analyzed after 1st and 2nd therapy cycles. Tumor normalized absorbed doses varied by a factor of 74 between 0.35 and 26 mGy/MBq. Averaged over all patients, a higher normalized mean tumor dose (10.51 mGy/MBq) was achieved for a peptide dose of 200 µg compared to 90 µg (4.58 mGy/MBq). Kidneys doses varied by a factor of up to 4 between patients (0.25-1.0 mGy/MBq) (independent of dose cycle and peptide dose) and by a factor of up to 2 between dose cycles. The mean kidney dose was 13.7% higher for the 90 µg peptide dose compared to 200 µg. Given the higher tumor dose, the mean therapeutic index of a 200 µg mass dose was considerably higher (16.95), compared to a 90 µg mass dose (9.63). This coincided with the observation, that lesion volume reduction was more pronounced after an initial treatment with a 200 µg mass dose. Biologically effective dose was only 5. 1%-19.3% higher than the absorbed dose for individual dose cycles. CONCLUSIONS: Higher peptide dose of 200 µg appears to be more suitable than 90 µg in terms of tumor dose, kidney dose, and therapeutic index for treatment with 177Lu-DOTATOC.

Multimodal Imaging of 2-Cycle PRRT with 177Lu-DOTA-JR11 and 177Lu-DOTATOC in an Orthotopic Neuroendocrine Xenograft Tumor Mouse Model.

Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin receptor (SSTR) analogs is a common approach in advanced neuroendocrine neoplasms. Recently, SSTR antagonists have shown promising results for imaging and therapy due to a higher number of binding sites than in commonly used agonists. We evaluated PRRT with SSTR agonist 177Lu-DOTATOC and antagonist 177Lu-DOTA-JR11 longitudinally in an orthotopic murine pancreatic neuroendocrine neoplasm model expressing human SSTR2. Morphologic and metabolic changes during treatment were assessed using multimodal imaging, including hybrid PET/MRI and SPECT/CT. Methods: In vitro radioligand binding and internalization assays and cell-cycle analysis were performed. SSTR2-transfected BON cells (BON-SSTR2) were used for in vivo experiments. Tumor-bearing mice received 2 intravenous injections of 100 µL of saline, 30 MBq of 177Lu-DOTATOC, or 20 MBq of 177Lu-DOTA-JR11 with an interval of 3 wk. Weekly T2-weighted MRI was performed for tumor monitoring. Viability of the tumor tissue was assessed by 18F-FDG PET/MRI once after PRRT. Tumor and kidney uptake of the respective radiopharmaceuticals was measured 24 h after injection by SPECT/CT. Results: Compared with 177Lu-DOTATOC, 177Lu-DOTA-JR11 treatment resulted in an increased accumulation of cells in G2/M phase. Animals treated with the SSTR antagonist showed a significant reduction in tumor size (P < 0.001) and an increased median survival (207 d; interquartile range [IQR], 132-228) compared with 177Lu-DOTATOC (126 d; IQR, 118-129). SPECT/CT revealed a 4-fold higher median tumor uptake for the antagonist and a 3-fold higher tumor-to-kidney ratio in the first treatment cycle. During the second therapy cycle, tumor uptake of 177Lu-DOTATOC was significantly lower (P = 0.01) whereas 177Lu-DOTA-JR11 uptake remained stable. Imaging of tumor morphology indicated comparatively larger necrotic fractions for 177Lu-DOTA-JR11 despite further tumor growth. These results were confirmed by 18F-FDG PET, revealing the least amount of viable tumor tissue in 177Lu-DOTA-JR11-treated animals, at 6.2% (IQR, 2%-23%). Conclusion:177Lu-DOTA-JR11 showed a higher tumor-to-kidney ratio and a more pronounced cytotoxic effect than did 177Lu-DOTATOC. Additionally, tumor uptake was more stable over the course of 2 treatment cycles.

A Cyanine-Bridged Somatostatin Hybrid Probe for Multimodal SSTR2 Imaging in Vitro and in Vivo: Synthesis and Evaluation.

Multimodal imaging probes have attracted the interest of ongoing research, for example, for the surgical removal of tumors. Modular synthesis approaches allow the construction of hybrid probes consisting of a radiotracer, a fluorophore and a targeting unit. We present the synthesis of a new asymmetric bifunctional cyanine dye that can be used as a structural and functional linker for the construction of such hybrid probes. 68 Ga-DOTATATE, a well-characterized radiopeptide targeting the overexpressed somatostatin receptor subtype 2 (SSTR2) in neuroendocrine tumors, was labeled with our cyanine dye, thus providing additional information along with the data obtained from the radiotracer. We tested the SSTR2-targeting and imaging properties of the resulting probe 68 Ga-DOTA-ICC-TATE in vitro and in a tumor xenograft mouse model. Despite the close proximity between dye and pharmacophore, we observed a high binding affinity towards SSTR2 as well as elevated uptake in SSTR2-overexpressing tumors in the positron emission tomography (PET) scan and histological examination.

Radixin modulates the function of outer hair cell stereocilia.

The stereocilia of the inner ear sensory cells contain the actin-binding protein radixin, encoded by RDX. Radixin is important for hearing but remains functionally obscure. To determine how radixin influences hearing sensitivity, we used a custom rapid imaging technique to visualize stereocilia motion while measuring electrical potential amplitudes during acoustic stimulation. Radixin inhibition decreased sound-evoked electrical potentials. Other functional measures, including electrically induced sensory cell motility and sound-evoked stereocilia deflections, showed a minor amplitude increase. These unique functional alterations demonstrate radixin as necessary for conversion of sound into electrical signals at acoustic rates. We identified patients with RDX variants with normal hearing at birth who showed rapidly deteriorating hearing during the first months of life. This may be overlooked by newborn hearing screening and explained by multiple disturbances in postnatal sensory cells. We conclude radixin is necessary for ensuring normal conversion of sound to electrical signals in the inner ear.

Relationship of Renal Function in Mice to Strain, Sex and 177Lutetium-Somatostatin Receptor Ligand Treatment.

AIM: Aim of the study was to establish parameters for 99mTc-MAG3 SPECT renal uptake kinetics in healthy SCID mice as a function of mouse strain and sex and to evaluate the feasibility of this method for detecting 177Lu-somatostatin receptor ligand (177Lu-SRL) treatment effects on kidney function. MATERIALS AND METHODS: Dynamic semi-stationary SPECT acquisitions (68 frames, total duration 35 min) was started prior to i. v. injection of 99mTc-MAG3 in 12 female and 12 male SCID mice. Additionally, 6 female SCID mice with neuroendocrine tumors were imaged 1-5 months after 177Lu-SRL (5 DOTATOC, 1 DOTA-JR11) treatment. Kidney function is expressed as maximum time to peak (Tmax), T50 and T25 in minutes (median [interquartile range]). Differences between groups were tested using the Mann-Whitney-U test, and SCID mouse parameters were compared with data for C57BL/6N mice from a recent publication. RESULTS: Significant sex-based differences in Tmax between strains were observed (females: C57BL/6N 1.6 [1.4-1.7], SCID 1.4 [1.3-1.5], p = 0.05; males: C57BL/6N 1.4 [1.3-1.4], SCID 1.6 [1.4-1.7], p = 0.04). In C57BL/6N mice, females showed a later Tmax (p < 0.01) than males. SCID mice showed no difference (p = 0.14). Treated SCID mice showed no significant delay in Tmax (2.0 [1.4-2.7], p = 0.15) but a significant delay in T50 (p = 0.02) and T25 (p = 0.01) compared to healthy untreated mice. CONCLUSION: This study demonstrated significant sex-related differences between SCID and C57BL/6N mouse strains in kidney function. Establishment of normal values for different strains and sexes therefore is important for experimental therapy studies. Renal SPECT imaging with 99mTc-MAG3 was sufficiently sensitive to detect 177Lu-SRL treatment toxic effects on kidney function in SCID mice.

CMKLR1-targeting peptide tracers for PET/MR imaging of breast cancer.

Background: Molecular targeting remains to be a promising approach in oncology. Overexpression of G protein-coupled receptors (GPCRs) in human cancer is offering a powerful opportunity for tumor-selective imaging and treatment employing nuclear medicine. We utilized novel chemerin-based peptide conjugates for chemokine-like receptor 1 (CMKLR1) targeting in a breast cancer xenograft model. Methods: By conjugation with the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), we obtained a family of five highly specific, high-affinity tracers for hybrid positron emission tomography/magnetic resonance (PET/MR) imaging. A xenograft model with target-positive DU4475 and negative A549 tumors in immunodeficient nude mice enabled CMKLR1-specific imaging in vivo. We acquired small animal PET/MR images, assessed biodistribution by ex vivo measurements and investigated the tracer specificity by blocking experiments. Results: Five CMKLR1-targeting peptide tracers demonstrated high biological activity and affinity in vitro with EC50 and IC50 values below 2 nM. Our target-positive (DU4475) and target-negative (A549) xenograft model could be validated by ex vivo analysis of CMKLR1 expression and binding. After preliminary PET imaging, the three most promising tracers [68Ga]Ga-DOTA-AHX-CG34, [68Ga]Ga-DOTA-KCap-CG34 and [68Ga]Ga-DOTA-ADX-CG34 with best tumor uptake were further analyzed. Hybrid PET/MR imaging along with concomitant biodistribution studies revealed distinct CMKLR1-specific uptake (5.1% IA/g, 3.3% IA/g and 6.2% IA/g 1 h post-injection) of our targeted tracers in DU4475 tumor tissue. In addition, tumor uptake was blocked by excess of unlabeled peptide (6.4-fold, 5.5-fold and 3.4-fold 1 h post-injection), further confirming CMKLR1 specificity. Out of five tracers, we identified these three tracers with moderate, balanced hydrophilicity to be the most potent in receptor-mediated tumor targeting. Conclusion: We demonstrated the applicability of 68Ga-labeled peptide tracers by visualizing CMKLR1-positive breast cancer xenografts in PET/MR imaging, paving the way for developing them into theranostics for tumor treatment.

Attenuated palmitoylation of serotonin receptor 5-HT1A affects receptor function and contributes to depression-like behaviors.

The serotonergic system and in particular serotonin 1A receptor (5-HT1AR) are implicated in major depressive disorder (MDD). Here we demonstrated that 5-HT1AR is palmitoylated in human and rodent brains, and identified ZDHHC21 as a major palmitoyl acyltransferase, whose depletion reduced palmitoylation and consequently signaling functions of 5-HT1AR. Two rodent models for depression-like behavior show reduced brain ZDHHC21 expression and attenuated 5-HT1AR palmitoylation. Moreover, selective knock-down of ZDHHC21 in the murine forebrain induced depression-like behavior. We also identified the microRNA miR-30e as a negative regulator of Zdhhc21 expression. Through analysis of the post-mortem brain samples in individuals with MDD that died by suicide we find that miR-30e expression is increased, while ZDHHC21 expression, as well as palmitoylation of 5-HT1AR, are reduced within the prefrontal cortex. Our study suggests that downregulation of 5-HT1AR palmitoylation is a mechanism involved in depression, making the restoration of 5-HT1AR palmitoylation a promising clinical strategy for the treatment of MDD.