CDKN1A is a target for phagocytosis-mediated cellular immunotherapy in acute leukemia.

Targeting the reprogramming and phagocytic capacities of tumor-associated macrophages (TAMs) has emerged as a therapeutic opportunity for cancer treatment. Here, we demonstrate that tumor cell phagocytosis drives the pro-inflammatory activation of TAMs and identify a key role for the cyclin-dependent kinase inhibitor CDKN1A (p21). Through the transcriptional repression of Signal-Regularity Protein α (SIRPα), p21 promotes leukemia cell phagocytosis and, subsequently, the pro-inflammatory reprogramming of phagocytic macrophages that extends to surrounding macrophages through Interferon γ. In mouse models of human T-cell acute lymphoblastic leukemia (T-ALL), infusion of human monocytes (Mos) engineered to overexpress p21 (p21TD-Mos) leads to Mo differentiation into phagocytosis-proficient TAMs that, after leukemia cell engulfment, undergo pro-inflammatory activation and trigger the reprogramming of bystander TAMs, reducing the leukemic burden and substantially prolonging survival in mice. These results reveal p21 as a trigger of phagocytosis-guided pro-inflammatory TAM reprogramming and highlight the potential for p21TD-Mo-based cellular therapy as a cancer immunotherapy.

Understanding of Future Prescribers About Antimicrobial Resistance and Their Preparedness Towards Antimicrobial Stewardship Activities in Pakistan: Findings and Implications.

Background: Insufficient antimicrobial-related training for physicians during their undergraduate education could have a negative impact on their prescribing. Unlike previous studies, this study not only explored the understanding and perception of Pakistani medical students about antibiotics and resistance, but also their preparedness towards antimicrobial stewardship programs. Methods: An online cross-sectional study was undertaken with final-year medical students using a validated questionnaire from January 2021 to May 2021. Descriptive and inference statistics were applied for data analysis. Results: Of 411 students, only 6.3% had undergone antimicrobial resistance (AMR) training. 16.1% of students believed that antibiotics are effective for viral ailments. More than half of the students agreed that AMR is a major healthcare problem in Pakistan (65.9%). Most students viewed poor infection control practices (66.9%), the use of too many broad-spectrum antibiotics (68.4%) for a longer duration (62.8%) with inadequate doses (67.9%) as the causes of AMR. The student's preparation was insufficient in interpreting microbiological and pathological results (26.3%), selecting the correct antibiotics (22.1%), and awareness of the antibiotic spectrum (20.9%). The median preparedness score showed significant differences with sex (p = 0.049), age (p < 0.001), institute type (p = 0.014), and family income (p = 0.006). Conclusion: Pakistani medical students showed adequate understanding of antibiotics, but lacked preparedness for several components of ASPs, including interpretation of microbiological results and spectrum of antibiotics. More steps need to be taken to prepare medical students for AMR and stewardship initiatives adequately.

Dysregulation of mitochondrial sirtuin genes is associated with human male infertility.

Mitochondrial sirtuins (SIRT3, SIRT4, SIRT5) are post-translational modifiers that regulate energy production, body homeostasis and mitochondrial activities via different substrates in response to environmental stressors. The present study aimed at assessing the expression of SIRT3, SIRT4, and SIRT5 in the semen of infertile men. Expression analysis was performed using q-RT PCR. All mitochondrial sirtuin genes were significantly down-regulated in the semen of infertile men compared to fertile men. Mitochondrial sirtuin genes expression levels were correlated with mitochondrial HSP90 expression. HSP90 expression was positively correlated with SIRT3, SIRT4 and SIRT5 expression in the semen of fertile men, while a negative correlation was observed between HSP90 in the semen of infertile men and mitochondrial sirtuin genes in the semen of fertile men. These data suggest that dysregulation of mitochondrial sirtuin genes causes mitochondrial dysfunction due to stress, which appears to be associated with human male infertility by compromising functional and structural sperm integrity.

Assessment of α-amylase and α-glucosidase inhibitory potential of Citrus reticulata peel extracts in hyperglycemic/hypoglycemic rats.

Diabetes mellitus is a metabolic disorder of carbohydrate metabolism. The management of Diabetes mellitus with phytochemicals is hallmark of this research. Citrus species are known for their health benefits and are used as traditional food in South East Asia. The total phenolic content of peels was analyzed using different solvents, while Gallic acid was used as standard. Both ethanolic, aqueous extracts of Citrus reticulata peel showed good inhibitory activity against amylase (90.67%, 15.33%) and moderate against glucosidase (70.8%, 14.8%), respectively. Sixteen rats were randomly divided into four groups (G1, G2, G3, and G4); G1 is a negative control (water), G4 is a positive control (Acarbose), while other two are experimental groups like G2 (fed with 100 mL and 20 mg/mL in hypoglycemic and hyperglycemic trials) and G3 fed with 200 mL and 40 mg/mL in hypoglycemic and hyperglycemic trials. A significant effect of treatments and value of time was found in hyperglycemic rats. Ethanolic extract showed a significant reduction in blood glucose levels in hypoglycemic (overnight fasting) rats which was comparable to the positive control. These results suggest that C. reticulata peels can contribute as a useful food ingredient as a potential antihyperglycemic agent in managing type 2 diabetes mellitus. In future, C. reticulata peel will be a good candidate for pharmaceutical industry.

HIV-1 Envelope Overcomes NLRP3-Mediated Inhibition of F-Actin Polymerization for Viral Entry.

Purinergic receptors and nucleotide-binding domain leucine-rich repeat containing (NLR) proteins have been shown to control viral infection. Here, we show that the NLR family member NLRP3 and the purinergic receptor P2Y2 constitutively interact and regulate susceptibility to HIV-1 infection. We found that NLRP3 acts as an inhibitory factor of viral entry that represses F-actin remodeling. The binding of the HIV-1 envelope to its host cell receptors (CD4, CXCR4, and/or CCR5) overcomes this restriction by stimulating P2Y2. Once activated, P2Y2 enhances its interaction with NLRP3 and stimulates the recruitment of the E3 ubiquitin ligase CBL to NLRP3, ultimately leading to NLRP3 degradation. NLRP3 degradation is permissive for PYK2 phosphorylation (PYK2Y402∗) and subsequent F-actin polymerization, which is required for the entry of HIV-1 into host cells. Taken together, our results uncover a mechanism by which HIV-1 overcomes NLRP3 restriction that appears essential for the accomplishment of the early steps of HIV-1 entry.

Anticancer chemotherapy and radiotherapy trigger both non-cell-autonomous and cell-autonomous death.

Even though cell death modalities elicited by anticancer chemotherapy and radiotherapy have been extensively studied, the ability of anticancer treatments to induce non-cell-autonomous death has never been investigated. By means of multispectral imaging flow-cytometry-based technology, we analyzed the lethal fate of cancer cells that were treated with conventional anticancer agents and co-cultured with untreated cells, observing that anticancer agents can simultaneously trigger cell-autonomous and non-cell-autonomous death in treated and untreated cells. After ionizing radiation, oxaliplatin, or cisplatin treatment, fractions of treated cancer cell populations were eliminated through cell-autonomous death mechanisms, while other fractions of the treated cancer cells engulfed and killed neighboring cells through non-cell-autonomous processes, including cellular cannibalism. Under conditions of treatment with paclitaxel, non-cell-autonomous and cell-autonomous death were both detected in the treated cell population, while untreated neighboring cells exhibited features of apoptotic demise. The transcriptional activity of p53 tumor-suppressor protein contributed to the execution of cell-autonomous death, yet failed to affect the non-cell-autonomous death by cannibalism for the majority of tested anticancer agents, indicating that the induction of non-cell-autonomous death can occur under conditions in which cell-autonomous death was impaired. Altogether, these results reveal that chemotherapy and radiotherapy can induce both non-cell-autonomous and cell-autonomous death of cancer cells, highlighting the heterogeneity of cell death responses to anticancer treatments and the unsuspected potential contribution of non-cell-autonomous death to the global effects of anticancer treatment.

Entosis: The emerging face of non-cell-autonomous type IV programmed death.

The present review summarizes recent experimental evidences about the existence of the non-cell-autonomous death entosis in physiological and pathophysiological contexts, discusses some aspects of this form of cell death, including morphological, biochemical and signaling pathways that distinguish non-cell-autonomous demises from other death modalities and propose to define this new modality of death as type IV programmed cell death.

Histatin peptides: Pharmacological functions and their applications in dentistry.

There are many human oral antimicrobial peptides responsible for playing important roles including maintenance, repairing of oral tissues (hard or soft) and defense against oral microbes. In this review we have highlighted the biochemistry, physiology and proteomics of human oral histatin peptides, secreted from parotid and submandibular salivary glands in human. The significance of these peptides includes capability for ionic binding that can kill fungal Candida albicans. They have histidine rich amino acid sequences (7-12 family members; corresponding to residues 12-24, 13-24, 12-25, 13-25, 5-11, and 5-12, respectively) for Histatin-3. However, Histatin-3 can be synthesized proteolytically from histatin 5 or 6. Due to their fungicidal response and high biocompatibility (little or no toxicity), these peptides can be considered as therapeutic agents with most probable applications for example, artificial saliva for denture wearers and salivary gland dysfunction conditions. The objectives of current article are to explore the human histatin peptides for its types, chemical and biological aspects. In addition, the potential for therapeutic bio-dental applications has been elaborated.

Multifaceted roles of purinergic receptors in viral infection.

Extracellular nucleotides and purinergic receptors participate in numerous cellular processes during viral infection. Despite their positive role in the immune response, purinergic signals can also favor the infection of cells by viruses and the pathogeny of viral diseases. Here, we highlight the multiple ambiguous roles of purinergic receptors in viral infections.

Extracellular ATP acts on P2Y2 purinergic receptors to facilitate HIV-1 infection.

Extracellular adenosine triphosphate (ATP) can activate purinergic receptors of the plasma membrane and modulate multiple cellular functions. We report that ATP is released from HIV-1 target cells through pannexin-1 channels upon interaction between the HIV-1 envelope protein and specific target cell receptors. Extracellular ATP then acts on purinergic receptors, including P2Y2, to activate proline-rich tyrosine kinase 2 (Pyk2) kinase and transient plasma membrane depolarization, which in turn stimulate fusion between Env-expressing membranes and membranes containing CD4 plus appropriate chemokine co-receptors. Inhibition of any of the constituents of this cascade (pannexin-1, ATP, P2Y2, and Pyk2) impairs the replication of HIV-1 mutant viruses that are resistant to conventional antiretroviral agents. Altogether, our results reveal a novel signaling pathway involved in the early steps of HIV-1 infection that may be targeted with new therapeutic approaches.

Pro-apoptotic function of checkpoint kinase-2 in syncytia elicited by the HIV-1 envelope.

Fusogenic HIV-1 isolates induce the fusion of infected and bystander cells. Such syncytia can be found as "multinucleated giant cells" in the brain from HIV-1-infected individuals, as well as in lymphoid tissues. Syncytia elicited by the HIV-1 envelope glycoprotein (Env) manifest the aggregation of PML in discrete nuclear bodies and the recruitment of TopBP1, NBS1 and ATM to DNA damage foci containing phosphorylated ATM and histone H2AX ("-H2AX). This DNA damage response then culminates in p53-dependent activation of the mitochondrial pathway of apoptosis. Here, we show that Env-elicited syncytia also manifest activating phosphorylations of the checkpoint kinases 1 and 2 (Chk1 and Chk2), and both Chk1 and Chk2 colocalize with "-H2AX foci. However, only the siRNA-mediated knockdown of Chk2, not the depletion of Chk1, inhibits mitochondrial outer membrane permeabilization and subsequent syncytial apoptosis. Depletion of PML, TopBP1, NBS1 or ATM inhibit the activating phosphorylation of Chk2. Altogether, these results indicate that Chk2 (but not Chk1) participates in the DNA damage-elicited pro-apoptotic cascade that leads to the demise of Env-elicited syncytia.